The study of the composition, structure, and properties of substances and their changes.
What is chemistry?
Organic chemistry.
What branch of chemistry is most concerned with the study of carbon compounds?
A substance that has a definite composition.
What is meant by the word “chemical” as used by scientists?
Basic research is carried out to increase knowledge, for example, how and why a reaction occurs.
Applied research is practical problem solving, for example, developing new compounds useful as refrigerants.
Technological development involves using existing knowledge to improve quality of life, for example, using optical fibers for communications networks.
Briefly describe the differences between basic research, applied research, and technological development. Provide an example of each.
Mass is a measure of an amount of matter.
Volume is a measure of an amount of space.
What is mass? What is volume?
The proportions of elements in a pure substance is fixed. In contrast, the proportions of elements in a mixture may vary.
How does the composition of a pure compound differ from that of a mixture?
A property is any characteristic of a substance or material. A property is useful for classifying unknown materials as members of known groups or subgroups of substances, or to identify substances directly.
Define “property”. How are properties useful in classifying materials?
Extensive properties depend on the amount of matter that is present. Intensive properties do not.
What is the difference between extensive properties and intensive properties?
A property that can be observed and/or measured without changing the identity of the substance. Examples include color, odor, length, size, mass, volume, weight, melting point, etc.
Define “physical property”. Give two examples of physical properties.
A property that describes the ability of a substance to undergo changes that alter its identity. Examples include the ability of burning, or rusting, or reacting with other specific chemicals, etc.
Define “chemical property”. Give two examples of chemical properties.
Physical change does not involve a change in a substance’s identity. Chemical change converts one substance into other substances.
Distinguish between a physical change and a chemical change.
A solid state has definite volume and definite shape, whereas a liquid has definite volume but takes the shape of its container.
How does a solid differ from a liquid?
Neither a gas or a liquid have definite shape. However a liquid does have definite volume, whereas a gas does not.
How does a liquid differ from a gas?
Liquids and gases take the shape of the container they are in.
How is a liquid similar to a gas?
A plasma is a high temperature physical state of matter in which atoms lose their electrons.
What is a plasma?
A change of a substance from one state of matter (solid, liquid, gas, plasma) to another.
What is meant by a change in state?
Elements of similar chemical properties are placed in the same vertical columns.
What is the significance of the vertical columns of the periodic table?
Chemical properties of elements vary from left to right along the rows.
What is the significance of the horizontal rows of the periodic table?
Metals (at left and center of table) are good conductors of heat and electricity. Nonmetals (at right of table) tend to be poor conductors of heat and electricity. Metalloids (on the zig-zag line of the table) are intermediate in properties and are semiconductors of heat and electricity. Noble gases (at extreme right vertical column) are generally unreactive.
Compare the physical properties of metals, non-metals, metalloids, and noble gases and describe where in the periodic table each of these kinds of elements is located.
Physical chemistry
In which of the six branches of chemistry would a scientist be working if they were investigating energy relationships for various reactions.
Organic chemistry
In which of the six branches of chemistry would a scientist be working if they were comparing properties of alcohols with those of sugars.
Biochemistry
In which of the six branches of chemistry would a scientist be working if they were studying reactions that occur during the digestion of food.
Analytical chemistry
In which of the six branches of chemistry would a scientist be working if they were carrying out tests to identify unknown substances.
Reactants are potassium and water. Products are potassium hydroxide and hydrogen.
Identify the reactants and products in the following reaction:
Potassium + water –> potassium hydroxide + hydrogen gas
Potassium + water –> potassium hydroxide + hydrogen gas
Element ‘X’ is most likely a nonmetal on the right side of the table. Element ‘Z’ is most likely a metal on the left side or center of the table.
Suppose element ‘X’ is a poor conductor of electricity and breaks when hit with a hammer. Element ‘Z’ is a good conductor of electricity and heat. In what area of the periodic table does each element most likely belong?
Physical change
Identify the following as a physical change or a chemical change: A piece of wood is sawed in half.
Chemical change
Identify the following as a physical change or a chemical change: Milk sours.
Physical change
Identify the following as a physical change or a chemical change: Melted butter solidifies in the refrigerator.
Potassium. Metal.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: K
Silver. Metal.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: Ag
Silicon. Metalloid.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: Si
Sodium. Metal.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: Na
Mercury. Metal.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: Hg
Helium. Nonmetal.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: He
Nitrogen. Nonmetal.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: N
Boron. Metalloid.
Use the periodic table to write the name of the element that has the following symbol and identify it as a metal, nonmetal, metalloid, or noble gas: B
Malleability. Ductility. Good conductor of electricity.
An unknown element is shiny and is found to be a good conductor of electricity. What other properties would you predict for it?
Applied research.
Identify the following as an example of either basic research, applied research, or technological research: A new type of refrigerant is developed that is less damaging to the environment.
Basic research.
Identify the following as an example of either basic research, applied research, or technological research: A new element is synthesized in a particle accelerator.
Technological research.
Identify the following as an example of either basic research, applied research, or technological research: A computer chip is redesigned to increase the speed of the computer.
Group 14. Period 2.
Use the periodic table to identify the group number and period number of the following element: Carbon (C).
Group 18. Period 3.
Use the periodic table to identify the group number and period number of the following element: Argon (Ar)
Group 6. Period 4.
Use the periodic table to identify the group number and period number of the following element: Chromium (Cr)
Group 2. Period 6.
Use the periodic table to identify the group number and period number of the following element: Barium (Ba)
The material must be a mixture.
Suppose different parts of a sample material have different compositions. What can you conclude about the material?
The material is either a pure substance (elemental or compound) or the material is a solution (a homogeneous mixture).
Suppose different parts of a sample have the same composition. What can you conclude about the material?
