Thinking and questioning is the start of the scientific inquiry process.
Scientific inquiry refers to the diverse ways in which scientists study the natural world and propose explanations based on the evidence they gather.
Scientists who possess this attitude are eager to find answers to different questions they have about the natural world.
Scientists who possess this attitude question the results of experiments.
C scientific inquiry.
Trying to explain why a cactus needs little water to survive is an example of
A(n) hypothesis is a statement that describes how to measure a particular variable or define a particular term.
C operational definition
n a scientific experiment, a statement that describes how to measure a particular variable or define a particular term is a(n)
What scientific attitude is especially important when a scientist’s results go against previous ideas?
websites containing false or misleading information
The critical evaluation of websites allows users to identify
advertisements can contain confusing, misleading information
Judging and evaluating advertisements requires critical thinking because
implementing the first solution to a problem identified
Which of the following is not an example of critical thinking?
writing a summary
Which of the following is not a step involved in critical thinking?
Factual information can be presented with bias.
It prevents them from injecting bias into their experiments
Scientists use critical thinking skills throughout the process of research and experimentation. Why is it important for scientists to remain open-minded about the information they come across in their experiments?
all of the above
When conducting scientific research or experimentation, researchers carefully analyze and evaluate results to determine a valid conclusion. A scientist conducts an experiment to determine how different brands of fish food affect tropical fish growth. The scientist determines that all of their fish grow better when fed a specific brand of fish food. Why would it be important to question the results of this experiment?
The scientific method helps scientists avoid injecting which of the following into their experiments?
They have an editorial process to correct inaccurate information.
Which of the following is not true concerning Internet websites?
Information based on opinions is valid.
The English physician Ronald Ross wanted to find the cause of malaria. Dr. Ross suggested that the Anopheles mosquito was responsible for the spread of malaria from person to person. This statement was not based on observation and was used as a starting point for his investigation. This suggestion was a
Dr. Ross knew that the parasite Plasmodium was always found in the blood of malaria patients. He thought that if the Anopheles mosquitoes were responsible for spreading malaria, then Plasmodium would be found in the mosquitoes. His idea was a
In a controlled experiment, the ____________________ is the group that receives some type of treatment.
A possible explanation, or ____________________, may be tested by experimentation.
A theory is an assumption made by scientists and implies a lack of certainty.
C observations, questions, hypothesis, predictions, controlled testing, conclusions.
Most typically, the order in which the steps of scientific investigations are applied is
A scientist who performs an experiment has no idea what the outcome of the experiment is going to be.
Theories can be proven by observations alone.
The independent variable is the variable that is changed in an experiment.
Five-year-old children have longer attention spans than three-year-old children.
By analyzing Emily’s observations, what could be a valid conclusion?
Observational data is easier to analyze and interpret when it is organized into tables, charts, or graphs.
When making observations, you should provide a general description of the subject, rather than going into too much detail.
The cats tend to eat more in the evening.
Katy works at a pet store, and is in charge of tracking the cat food supply for the morning, afternoon, and evening shifts. There are currently six cats at their store, and each cat had full food bowls during the morning and afternoon shifts, throughout the entire shift. Each day, the evening shift person replenished the food bowls at the end of their shift. What is the pattern Katy could note from this data?
Female chimpanzee walks away when male chimpanzee approaches
Collin is conducting a study about chimpanzee communication methods. Which of the following note excerpts from his recent trip to the zoo would be good to include in his study?
Research any and all data pertaining to the Roswell area, and unidentified flying objects reported in the sky
Scientists follow specific processes in order to determine valid explanations and conclusions from observations. David observed strange lights in the sky above his home outside of Roswell, New Mexico. The only explanation that makes sense to him is that there are UFOs in the area. What should David do next to verify his explanation?
Researched information can never be biased.
For a specific graduating class at Rydell High School, the majority of male students preferred science courses over language arts, and the majority of female students preferred language arts courses over science
Scientists follow specific processes in order to determine valid explanations and conclusions from scientific data. Students graduating from Rydell High School fill out an exit survey the last week of school. When students were asked to compare language arts courses with science courses, 20% of males reported preferring language arts and 80% reported preferring science. For females, 90% reported preferring language arts and 10% reported preferring science. Which of the following would be a valid conclusion based on the data from this study?
The city of San Francisco reported more missing dogs the week before a massive earthquake than any other week of the year. Therefore, this is factual evidence that dogs can sense impending danger.
Courtney believes that the dinosaurs went extinct as a result of a giant asteroid hitting the earth. Scientists discovered a 150 km wide crater dating back to the time of their extinction, according to the fossil record. The crater and the fossil record are examples of researched data that support Courtney’s explanation.
Students at Allendale High School were tardy most often for fourth hour, right after lunch. Therefore, the administration decided to close campus for lunch. As a result, the number of students tardy for fourth hour drastically decreased. When questioned, the principal could say that open campus lunch was a contributing factor to student tardiness.
Male pattern baldness is a sex-linked trait, carried on the X sex chromosome. Therefore, genetics is a contributing factor to premature balding.
People with slow metabolisms have lower basal metabolic rates
Michele believes she cannot lose weight because she has a slow metabolism. Of the research she has done on the subject, which would be considered reliable?
Research data to find concrete evidence of a link between the moon cycle and human behavior
Every time there is a full moon, Mrs. Cook insists that students in her classes display strange behavior. What would be the best way for her to prove the validity of her theory?
research data on the subject, and analyze it for reliability
In order to construct a valid criticism, it is important to
What technique is used to separate the different cell parts?
The metric system is based on multiples of 100.
prove that the hypothesis is wrong
A common technique used in the laboratory is using the deductive approach to the scientific method. What is the purpose of this approach?
What scientific tool has led scientists to put more focus on inductive research methods?
The basic unit of mass in the International System of Units, or SI, is the
Which approach to biology does Jeff Lichtman favor that is not common in his field of study?
In a laboratory, you are responsible for your own safety, as well as the safety of your teacher and classmates.
A specimen smaller than 0.2 micrometers must be completely dried out before being studied using this type of microscope.
This type of microscope is generally used in high-school laboratories.
A revised version of this system is called SI, an abbreviation for the Système International d’Unités.
amount of time spent swimming
Which variable mentioned in Table 2-1 is kept constant?
The best type of graph to illustrate the change in air temperature over a period of time would be a _________ graph.
From the choices provided below, which stroke should a swimmer choose to burn the most calories?
The way that the data is organized.
Which of the following best describes the advantage of having data presented in a table over a paragraph?
During which year was the population of the United States about 150,000,000?
What would be an appropriate means of organizing the results of the experiment shown above?
A 77-kg male looking to burn 120 calories for 30 minutes of swimming should choose the fast crawl stroke.
Which element represents 10% of the elements in the human body?
A circle graph is always based on percentages.
models are non-visual ways of communicating how someone thinks about something in the natural world.
Maps are examples of ____ models that people might use everyday.
all of the above
Models can be used to describe which of the following environments?
A globe is an example of a physical model.
Computer models can be touched.
Only scientists use models.
Scientific models are often used to help scientists understand a problem.
Models may change as new discoveries are made.
make a hypothesis
Models can do all of the following EXCEPT
Diagram the flow of oxygen-rich blood through the body of a non-smoker. Then diagram the flow of blood with less oxygen (from airway resistance) through the body of a smoker
Coach Taylor is trying to explain the negative side effects smoking has to athletic performance. Which of these options include both a scientific model and a connection to Coach Taylor’s topic of athletic performance?
Four earth models, each with a different tilt to represent the earth’s position relative to the sun, lined up in order of season
Amanda is doing a report for her Earth Science class about the four seasons. Which of the following would be an effective scientific model to incorporate in her project?
When modeling a scientific process, it is more important to organize the parts in a way that makes sense to you than to list them sequentially.
A scientific model is easier to interpret and understand when it includes the main parts or processes, rather than every detail of every part or process.
Connie chooses influenza as her current event, since the article is being written during flu season. For her visual aid, she models the life cycle of the flu virus.
Connie needs to choose a current event to write about for the school newspaper. Her teacher would also like the article to include a visual aid, modeling a system or cycle. Of these options, which would best satisfy the assignment requirements?
perfecting a method for producing nylon fibers
Which of the following best describes an example of applied chemistry?
Seeks to gain knowledge for the sake of knowledge itself
studying chemicals containing carbon
Which of the following best describes an example of pure chemistry?
The study of chemicals containing carbon is traditionally called what type of chemistry?
The study of chemicals that, in general, do not contain carbon is traditionally called what type of chemistry?
Which field of science studies the composition and structure of matter?
The study of matter and the changes it undergoes
Which of the following is not a state of matter?
has mass and takes up space.
Matter is defined as anything that
Each molecule of iron oxide, Fe2O3, contains ____________________ atom(s) of iron.
The chemical symbol for sulfuric acid is H2SO4. How many atoms are contained in each molecule of sulfuric acid?
two hydrogen atoms and one oxygen atom.
The chemical formula for water, H2O, means that each water molecule contains
Covalent and Ionic
What kinds of bonds can happen between the elements of a compound?
By what means (or force) can the atoms in compounds be separated?
The chemical formula for a molecule that contains two chlorine (Cl) atoms is _
A substance that is made of atoms of more than one type bound together is called a(n)
The weight of a substance is defined as its mass divided by its volume.
-253 degrees C
Hydrogen is a liquid below what temperature?
A ______ property describes how a substance acts when it reacts with other substances.
Lead has a density of 11.3 g/cm3 and a mass of 282.5 g. What is its volume?
A liquid changes rapidly into a gas at the liquid’s
-183 degrees C
What is the boiling point of oxygen?
reacts with other substances.
Knowing the chemical properties of a substance will tell you how the substance
The color of a substance is a physical property.
A substance has a mass of 360 g and a volume of 7.5 cm3. What is its density?
Grinding wheat in to flour is a
They can be reversed by physical changes.
Which of the following is not true about chemical changes?
We inhale oxygen and exhale carbon dioxide as a result of a ______ change in our bodies.
Chemical changes can be reversed by physical changes.
What kind of chemical change involves breaking down substances using electricity?
evaporation of water
Which of the following is not a potential sign of chemical change?
Digesting food is an example of
What chemical change occurs when a more reactive substance replaces a less reactive substance in a compound?
A physical change differs from a chemical change in that waste products are formed through chemical changes.
Solids that have particles arranged in a regular, repeating patterns are known as crystalline solids.
In crystalline solids, the particles are not arranged in a regular pattern.
Which state of matter undergoes changes in volume most easily?
The resistance of a liquid to flowing is its
A liquid does not have a definite shape, but it does have a definite volume.
In a solid the particles are packed closely together, but they can move past each other freely.
Particles in a liquid move around just as freely as particles in a solid.
In which state of matter are particles packed tightly together in fixed positions?
Adding or removing energy
What is needed to cause a change in the state of matter?
Evaporation only occurs at the surface of a liquid.
When temperatures are near absolute zero, what process causes atoms to begin to clump?
In cold climates, the amount of snow on the ground may decrease even if the temperature stays below zero degrees Celsius. The process that best explains this event is
The change from liquid to solid, or the reverse of melting, is called
a solid turns directly into a gas.
During the process of sublimation,
the pressure of the air above the substance.
The boiling point of a substance is affected by
The opposite of vaporization is called
a liquid becoming a gas
What is vaporization?
occurs when particles in a gas lose enough energy to form a liquid.
Which of the following does NOT indicate that a chemical change may have taken place?
fermenting of cheese
Which of the following is NOT a physical change?
Which of the following processes does NOT involve a change in chemical properties?
In the chemical reaction in which sucrose is heated and decomposes to form carbon dioxide and water, which of the following is a reactant?
a chemical change
When paper turns yellow-brown upon exposure to sunlight, what type of change is likely taking place?
There must be a change in chemical properties.
What must occur for a change to be a chemical reaction?
Check the composition of the sample before and after the change.
What must be done to be certain that a chemical change has taken place?
Which of the following is NOT an example of a physical change?
The total mass of the reactants equals the total mass of the products.
Which of the following is true for all chemical reactions?
a substance formed in a chemical reaction
When a liquid is heated, the temperature stops rising at the liquid’s
The process by which a solid becomes a liquid is
Which of the following has a melting point greater than room temperature?
The direct change of a substance from a solid to a gas is called
The escape of molecules from the surface of a liquid is known as
What happens to the rate of evaporation of a liquid as the liquid is cooled?
A phase is a region with homogeneous (uniform) properties and a
conversion between states is called a “phase transition”
conversion between states is called a “phase transition”
What is the difference between a phase and a phase transition?
Both a and b
What is true about the phase changes of water?
gases and liquids only
Which states of matter can flow?
solid to gas
Sublimation is the process where a substance changes from
Water boils at 373 K. The molar enthalpy of vaporization for water is 40.7 kJ/mol. If one mole of water is at 373 K when it starts to boil, its temperature when it all has boiled will be
Enthalpy changes accompanying a change of state are _____ than those accompanying the heating of a substance at each state.
The measure of disorder in a system is its
A curve showing the relationship between temperature and time for a given amount of liquid heated a constant rate is a __________ curve.
Of the following forms of carbon dioxide, which has the lowest entropy?
enthalpy of vaporization.
For one mole of any substance at its boiling point, the difference in the enthalpy of its vapor and the enthalpy of its liquid is its molar
amount of heat added and temperature
In graphing enthalpy, entropy, and state changes, which two variables are included?
Which of the following characteristics of a substance is not affected by enthalpy and entropy?
According to Boyle’s law, when the pressure on a gas increases at constant temperature, its volume
When the temperature is constant, the volume of a gas will decrease as the pressure decreases.
the volume of the balloon decreases.
When an inflated balloon is exposed to cold air,
In a flexible container, when the temperature of a gas increases, the volume of the gas will increase.
The force of a gas’s outward push divided by the area of the walls of the container is the gas’s
In a rigid container, when the speed of the gas molecules decreases, the pressure of the gas also decreases.
Volume is a measurement of how fast particles of a substance are moving.
If the temperature increases in a sample of gas at constant volume, then its
According to Charles’s law, when the temperature of a gas increases at constant pressure its
Assuming that the air temperature is constant, what happens to a hot air balloon if it goes too far up in the atmosphere, where the outside air pressure is much less than the inside are pressure of the balloon?
When a gas is compressed in a cylinder the amount (mass) of gas
Factors that affect the pressure of a gas include the amount of gas, the volume, and the temperature.
If a balloon is squeezed, what happens to the pressure of the gas inside the balloon?
A gas is located inside a closed container. If the gas is allowed to occupy more volume inside the container, what will happen to the pressure? (Note: There is no gas added to the container.)
The pressure will increase.
If the volume of a container of gas is reduced, what will happen to the pressure inside the container?
What would be the effect on pressure as the number of particles of a gas, inside a closed container, increases?
a measure of how much the volume of matter decreases under pressure
Volume of the gas particles is smaller than the volume of the gas
How does the volume of the particles in a gas compare to the volume of the gas?
The pressure decreases.
What happens to the pressure of a gas inside a container if the temperature of the gas decreases?
the pressure of the gas is directly proportional to its temperature in Kelvin
In general, for a gas at a constant volume,
According to Charles’s Law, what happens to the volume of a gas when temperature decreases? Assume the gas is at constant pressure.
the product of the pressure and volume
When the temperature and number of particles of a gas are constant, which of the following is also constant?
A sample of a gas occupies a volume of 752 mL at 25°C. What volume will the gas occupies if the temperature increases to 50°C, if the pressure remains constant?
Pressure and volume changes at a constant temperature can be calculated using
A gas occupies a volume of 2.4 L at 14.1 kPa. What volume will the gas occupy at 84.6 kPa?
According to Avogadro’s Law, how many molecules of any gas at STP are present in a volume of 22.41 L?
If a sealed syringe is heated, in which direction will the syringe plunger move?
A sample of gas occupies 17 mL at -112
the ratio of the temperature to volume in Kelvin
When the pressure and number of particles of a gas are constant, which of the following is also constant?
atoms can join to form molecules.
Dalton’s atomic theory stated that every element was made of atoms that could not be subdivided, atoms of the same element are alike, and
Neutrons add only ____ to an atom.
The number of protons in the nucleus
What is the atomic number of an element?
The nucleus of an atom can have either a positive or negative charge.
According to modern atomic theory, it is nearly impossible to determine an electron’s exact
The charge of an electron is
The word atom comes from a Greek word that means “able to duplicate”
Electrons travel in definite circular pathways around the nucleus.
Which of the following statements about the atom is false?
A form of an atom with a different number of neutrons
What is an isotope?
What is the maximum number of orbitals in the p sublevel?
region of high probability of finding an electron
involves finding an electron somewhere in a specific orbital
The quantum mechanical model of the atom
According to Schrodinger’s model electrons are found in fixed orbits around the nucleus.
The letter “p” indicates the
What is the amount of energy needed to move an electron from one energy level to another?
It did not include electrons
What was the problem with Rutherford’s model?
They are smaller in magnitude than those between lower energy levels.
How do the energy differences between the higher energy levels of an atom compare with the energy differences between the lower energy levels of the atom?
What is the specific energy an electron in an atom or other system can have?
The shape (not the size) of an electron cloud is determined by the electron’s
How does the energy of an electron change when the electron moves closer to the nucleus?
The electrons move in orbitals around the protons, which are at the center of the atom
In Bohr’s model of the atom, where are the electrons and protons located?
In the Bohr model of the atom, an electron in an orbit has a fixed _
Isotopes have variable numbers of electrons.
Atoms of elements that are in the same group have the same number of
The order of elements in the periodic table is based on the atomic number.
Ions can have a positive or negative charge.
Because atoms of elements in the same group of the periodic table have the same number of neutrons, they have similar properties
Valence electrons determine an atom’s
protons plus the number of neutrons.
An atom’s mass number equals the number of
An atom of potassium has an atomic mass of 39 amu and an atomic number of 19. It therefore has ______ neutrons in its nucleus.
It is a weighted average, so common isotopes have a greater effect than uncommon ones.
Which statement about an element’s average atomic mass is correct?
Elements are placed in the same column of the periodic table because they share the same number of valance electrons.
Dot diagrams are used to represent
What kind of group 1 atoms are the most reactive?
The energy levels of an atom are occupied by
Most of an atom is empty space.
How many dots are shown in the electron dot diagram for calcium, in group II and period 4 with 20 protons and 20 electrons?
Atoms of different elements have different numbers of protons.
How many electrons do alkali metals have in their outer shell?
Helium is considered a complete atom with the least reactivity of the elements on the periodic table.
The number of electrons in an atom decreases as you move from left to right in the periodic table.
Which of the following is the Aufbau diagram for Sodium?
a principal energy level
Each period in the periodic table corresponds to
Which of the following electron configurations represents the most chemically stable atom?
What element in the fourth period is an exception to the Aufbau principle?
Which block of elements do the halogens belong to?
How many electrons are in the highest occupied energy level of a group 5A element?
What group of elements are contained in the p-block?
What is the maximum number of electrons an f-orbital will hold?
number of valence electrons.
Elements in the same group have the same
period 3, group 5A
Identify the period and group of the element that has the electron configuration 1s22s22p63s23p3.
Cations form when an atom loses electrons.
Which of the following statements is true about ions?
Charge, atomic radius, orbital penetration, and electron pairing
What factors that affect ionization energy?
What element in the second period has the largest atomic radius?
It tends to decrease.
How does atomic radius change from left to right across a period in the periodic table?
Which element on the periodic table is the most electronegative?
lose electrons when they form ions
The metals in Groups 1A, 2A, and 3A
increase in atomic size
Which of the following factors contributes to the decrease in ionization energy within a group in the periodic table as the atomic number increases?
Which of the following elements in group 1 of the periodic table has the smallest atomic radius?
It tends to increase.
How does atomic radius change from top to bottom in a group in the periodic table?
ionization energy increases
As you move from left to right across the second period of the periodic table
can be pulled out, or drawn, into a long wire.
The heaviest naturally occurring element is
liquid at room temperature.
Most metals are NOT
Most of the elements in the periodic table are _
calcium and magnesium.
The two most common alkaline earth metals are
Elements that easily transmit electricity and heat display the property known as conductivity.
in Group 1, the first column on the left.
In the periodic table, the most reactive metals are found
Describing a metal as malleable means that it can be pounded into a new shape.
What is another name for the rare earth elements?
The most chemically reactive metals are in Group 1 of the periodic table.
The element’s nuclei would break apart very quickly.
Why would it probably be very difficult to determine the chemical and physical properties of a newly discovered synthetic element?
What is the maximum number of electrons that transition metals can hold in their second to last shell?
can be pulled out, or drawn, into a long wire.
A material is said to be ductile if it
Which group of elements shares characteristics with both metals and nonmetals?
a substance that will conduct electricity only under certain conditions
Fluorine, chlorine, bromine, and iodine are part of a family called
In general, metalloids are slightly reactive.
The elements that do not ordinarily form compounds are
family of elements that gain or share three electrons when they react
In general, the physical properties of nonmetals are similar to the properties of metals.
With the exception of one element, the elements that form diatomic molecules are commonly found on this side of the periodic table
Alpha particles are the most penetrating.
Radioactive decay can involve electrons.
In 1896, the French scientist Henri Becquerel discovered
Gamma rays are negatively charged.
unhealthy human cells are destroyed.
In radiation therapy,
give off nuclear radiation.
During radioactive decay, atomic nuclei of unstable isotopes
Radioactivity was discovered by Albert Einstein.
A piece of paper will provide protection from
A(n) ______ particle consists of two protons and neutrons.
negative electron of the other atom.
When two hydrogen atoms bond, the positive nucleus of one atom attracts the
12 atoms of carbon.
Each molecule of table sugar, C12H22O11, contains
When elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.
The forces that hold different atoms or ions together are
Unlike a mixture, a compound has a chemical formula that is always the same.
always contains the same elements in the same proportion.
A compound differs from a mixture because it
What are substances that have the same composition, but different structures, known as?
their molecules have very little attraction for one another.
Gases take up a lot of space because
From metal to non-metal
Which direction do electrons move in when metals react with non-metals?
The overall charge of an ionic compound is
Nitrate (NO3-), ammonium (NH4+), and carbonate (CO32-) are examples of polyatomic ions.
They form hard, brittle crystals with characteristic shapes.
Which of the following is a characteristic property of ionic compounds?
Ionic compounds have high melting points because a lot of energy is needed to break the bonds between the ions.
When ions having a positive charge form bonds with ions having a negative charge, the charge on the resulting compound is negative.
What is the chemical name for the compound with the formula Na2S?
oppositely charged ions.
An ionic bond is the attraction between
Ions that are made of more than one atom are examples of
In the chemical formula for an ionic compound, which item is written first?
A covalent bond in which electrons are shared unequally is
An ionic compound is a compound that consists of molecules made of atoms that are covalently bonded.
two pairs of electrons shared between two atoms
What is a double bond?
Because the electrons in a molecule of hydrogen fluoride (HF) are more strongly pulled toward the fluorine atom, the molecule is nonpolar.
do not break up into ions.
Molecular compounds do not conduct electricity because they
A nonpolar bond is formed when two atoms share electrons unequally.
The liquids do not mix.
Water is polar and oil is nonpolar. What happens when the two liquids are poured into the same container?
How many covalent bonds can nitrogen have?
When more valence electrons of a metal are shared, its melting point tends to be
The metal _______, which has a melting point of over 3000°C, is used to make light bulb filaments.
Delocalized valence electrons
Why are metals very good conductors of electricity?
the attraction of valence electrons for metal ions
Mercury hangs on to its valence 6s electrons very tightly and does not share them easily
How do the valence electrons of mercury make its bonding weak?
Which of the following is the metallic property allowing it to be shaped without breaking?
Metal alloys are made in order to use the best properties of each metal.:
A mixture of elements that has metallic properties
Physical properties of metals are independent of the number of delocalized electrons they have.
Weak dipole-dipole forces result in a low melting point.
All of the above
Which molecules retains the shape needed to be biologically active due to intermolecular forces?
The type of bonding in a substance that is a liquid at room temperature will most likely be covalent.
results from a temporary dipole.
A London dispersion force is considered a dipole-dipole force because it
London dispersion forces occur between molecules that are
London dispersion forces exist between polar molecules and result from temporary dipoles.
The attraction of the positive end of one molecule for the negative end of a neighboring molecule is a(n)
both the size of the ion and its charge.
The strength of the forces between ions depends on
The intermolecular force between molecules of oxygen is dipole-dipole in nature.
A hydrogen bond is a special form of a(n)
When sodium chloride is dissolved in water, sodium cations (Na+) and chloride anions (Cl-) are formed. What kind of reaction is taking place?
Atoms are rearranged.
What happens in a chemical reaction?
The energy source in photosynthesis is
A change of color is a sign that a chemical reaction is taking place.
What type of chemical reaction is the opposite of synthesis?
In a chemical reaction, atoms are created or destroyed.
An endothermic reaction is one in which heat is transferred from the surroundings to the reactants.
the reactants to the surroundings.
In an exothermic reaction, energy is transferred from
A substance that undergoes a change in a chemical reaction is
carbon dioxide and water.
When methane reacts with abundant amounts of oxygen, the products are
Which of the following is an example of a decomposition reaction?
An example of a double displacement reaction is
In a redox reaction, the substance that accepts electrons is said to be
The product of the synthesis reaction between sodium and chlorine gas is
loses three electrons.
When iron reacts with oxygen to form rust, each iron atom
a single-displacement reaction
What kind of reaction occurs when potassium is placed in water?
An example of a single displacement reaction is
9.55 mol of Al
How many moles are equivalent to 5.75×1024 atoms of Al?
2.4 ´ 10^24 molecules
Calculate the number of molecules in 4.0 mol H2O.
7.95 ´ 10^24 atoms
Calculate the number of atoms in 13.2 mol copper.
How many moles of Ag contain 4.49 x1023 atoms Ag?
A sample of a substance contains 3.70 ´ 1023 formula units. How many moles are contained in the sample?
6.23 mol carbon dioxide
How many moles are equivalent to 3.75×1024 molecules of carbon dioxide?
What is the SI unit for molar mass?
One mole of copper will contain an amount of copper atoms equal to Avogadro’s number.
It is a way to compare the amounts of any materials in the same chemical equation using the formula weights and the coefficients of the materials in the equation
What is stoichiometry?
1.8 X 10^24
How many molecules are in 3.0 moles of Carbon Dioxide (CO2)?
What is the SI base unit used to measure the amount of a substance?
In the chemical equation 652-02-05-03-00_files/i0030000.jpg, there is one FeS molecule.
A balanced chemical equation indicates both the number of particles of reactants and products and the number of
In the reaction 652-02-05-03-00_files/i0120000.jpg, if you start with 4 H2O2, how much O2 will you end up with?
mass to be conserved.
A balanced chemical equation shows the proportions of reactants and products necessary for
numbers in front of molecules.
A chemical equation is balanced by changing or adding
When there is no change to the atoms in the compound
When can a compound be treated like an element when balancing chemical equations?
In a chemical reaction, the combined molar masses of the reactants is greater than the combined molar masses of the products.
Balanced equations account for the conservation of mass.
Suppose zinc combined with hydrochloric acid and produced zinc chloride and hydrogen gas in the following equation 652-02-05-03-00_files/i0020000.jpg. According to the equation, how many HCl molecules are needed to fulfill the conservation of mass?
In the chemical equation 652-02-05-03-00_files/i0030000.jpg, there is one FeS molecule.
total mass of the reactants.
In a balanced chemical reaction, the total mass of the products always equals the
In the reaction 2Ca + O2 → 2CaO for every 2 Ca you will need how much O2?
Consider the law of conservation of mass. In the reaction 652-02-05-03-00_files/i0140000.jpg, how much O2 will you need for every H2S?
Because each nitrogen molecule contains two nitrogen atoms
Why is only one molecule of N2 needed to produce 2 molecules of NH3?
Reduce the temperature.
What could you do to make yeast dough rise more slowly?
speed up a specific biochemical reaction.
An enzyme is a special kind of catalyst that works to
In equilibrium, the forward and reverse reaction rates must be equal.
What is the relationship between chemical equilibrium and the rates of forward and reverse reaction?
releases energy as heat
beaker containing reactants is cooled
requires energy as heat.
Le Châtelier’s principle states that increasing temperature favors a reaction that
At equilibrium, no chemical reactions take place.
Increasing the size of the molecules
Which of the following factors does not increase reaction rates?
keep moving forward to produce more products
According to Le Chatelier’s Principle, if products are removed from a system at equilibrium, the reaction will
An enzyme is a protein that acts as a catalyst in a chemical reaction that takes place in a living thing.
When a reaction is at equilibrium, increasing pressure will favor the reaction that produces more gas.
When a chemical reaction and its reverse are occurring at the same time and at the same rate, the reaction has achieved
all of the above
The amount of heat transferred from an object depends on which of the following?
It does not depend on the process used to arrive at that state
Which statement is TRUE about state functions?
The heat content of a system is equal to the enthalpy only for a system that is at constant
absorbed by the surroundings
If heat is released by a chemical system, an equal amount of heat will be
heat content of a system at constant pressure
In a calorimeter, the energy content of a substance is calculated from measurement of the temperature change in a known mass of
thermal energy and enthalpy
Which thermochemical quantity is an extensive property?: temperature, thermal energy, heat, enthalpy.
Both a and b
What steps should be used in solving calorimetry problems?
greater than the energy stored in the bonds of the products
In an exothermic reaction, the energy stored in the chemical bonds of the reactants is
heat of reaction
The enthalpy change for a chemical reaction exactly as it is written is called the
When making lemonade from a powder, the solvent would be the
by testing the electrical conductivity of the solution
How can a scientist safely tell whether an unknown solution is salt in water or sugar in water?
A solute is a mixture in which particles can be seen and easily separated.
A liquid mixture in which particles can be seen and easily separated by settling or filtration is a
solid particles dispersed in water.
A colloid is
A substance that is present in a solution in a smaller amount and is dissolved by the solvent is called the solute.
each of its particles becomes surrounded by water molecules.
When a solid compound dissolves in water,
The water will boil at a higher temperature.
How would a solute affect the boiling point of water?
The particles in a suspension are larger than the particles in a solution but are still too small to be seen easily.
solids break up into individual neutral particles when dissolved in a solvent.
A solute will probably dissolve best in a
When you add so much solute that no more dissolves, you have a
In higher pressure environments, less gas can be dissolved in a solvent.
Oil is soluble in water
When you heat water, more sugar can be dissolved in it.
Concentration is always measured in grams of solute divided by liters of solution.
Among the factors that affect the solubility of a substance are type of solvent and temperature.
they are different substances
If two unidentified solids of the same texture and color have different solubilities in 100 grams of water at 20°C, you could conclude that
Because solubility is a characteristic property of matter, it can be used to help identify a substance.
The solute will begin to form crystals
What will happen if a single crystal is introduced into a super-saturated solution?
Bases feel slippery and taste sour.
“eat away” at other materials.
Acids are described as corrosive because they
Which of the following properties is NOT characteristic of acidic solutions?
turns red lithmus paper blue
They react with oils and fats
Why do bases make good household cleaners?
They turn blue litmus paper red.
They react with oils and fats
Acids and bases have many uses around the home and in industry.
Salt and hydrogen
What is produced when an acid reacts with a metal?
A base is a compound that turns litmus blue and is often found in soaps and detergents.
The products of a neutralization reaction are acids and bases.
Which salt is produced when copper oxide reacts with hydrochloric acid?
The pH scale measures the concentration of hydroxide ions.
All dilute basic solutions are weak bases.
acid and a base.
Neutralization is a reaction between a(n)
In water, bases form
between 5 and 7.
Normal rainfall is slightly acidic, which means its pH must be
When hydrochloric acid is dissolved in water the reaction produces carbon dioxide and oxygen.
An ionic compound formed by a neutralization reaction
You can find the pH of a substance by using