Simple tests to understand chemical bonds Essay

Purpose

The purpose of this experiment was to pattern general research lab processs, ” blending liquids and solids, mensurating little alterations in temperature every bit good as detecting reactions and other alterations. “ ( Lane, 2009a )

Introduction

The rule of why liquids can be mixable which can be summarized as “ like mixes with similar ” ( Lister and Renshaw,2000: p118 ) . When liquids meet other substance with similar bonds, they both produce shared intermolecular forces to blend together. However, some liquids are non mixable when they are assorted, because energy demands to be supplied to do attractive forces to organize a mixture with different constituents.

Again Lister and Renshaw provinces ( 2000 ) , liquids can blend with solids harmonizing to the similar regulation “ like dissolve like ” . Solids form the bonds can fade out in the same type of dissolver.

Sodium is a really reactive metal which must be handled with attention, hence Na must be kept under oil to protect it from responding with O in the air.

4Na ( s ) + O2 ( g ) & gt ; 2Na2O ( s )

Sodium besides reacts with H2O, here moving as an acid,

2Na ( s ) + 2H2O ( cubic decimeter ) — & gt ; 2NaOH ( aq ) + H2 ( g )

The equation shows that Na hydrated oxide is produced. ( Lane, 2009b )

Methodology

Equipment

Ethyl alcohol: CH3CH2OH

Hexane: CH3CH2CH2CH2CH2CH3

Distilled Water

Potassium Carbonate ( s ) : K2SO4

Copper Sulphate ( s ) : CuSO4

Potassium ( s ) : Kelvin

Small bottle of Sodium

Small bottle of Iodine ( s )

3 pipettes ( for 3 different liquids )

Large and little trial tubings

A thermometer

A beaker

A conelike flask

Pincers

Method

The experiment was divided into 3 parts: commixture liquids ; blending liquids and solids, detecting the reaction of Na and K with H2O.

1. Blending liquids

First, with a thermometer to mensurate the temperature of the H2O in the beaker, so utilizing the pipette, 1 cm3 H2O was put into a big trial tubing. Using another pipette 1 cm3 of ethyl alcohol was added into the tubing. The tubing was shaken gently and the temperature was measured once more. And so maintain as tubing A for 2nd portion.

1 cm3 H2O was put into a trial tubing utilizing a pipette, and so utilizing the pipette 1 cm3 of hexane was added into another tubing. After agitating the tubing gently and detecting what happened, the temperature was measured, and so labeled as tubing B.

Following, utilizing the pipette, 1 cm3 of hexane was poured into a trial tubing. Meanwhile, 1 cm3 of ethyl alcohol was poured into the tubing. The tubing was shaken gently and was observed and the temperature was measured. Another 1 cm3 of ethyl alcohol was poured into the tubing and labeled as tubing C.

2. Blending liquids and solids

Initially, some K carbonate was placed into the tubing A. The tubing was shaken and observed.

Second, 1 cm3 H2O was poured into a little trial tubing. 1 cm3 of hexane and ethyl alcohol were poured into 2 big trial tubing. After utilizing a spatula placed a little sum of Cu sulfate into each tubing, these tubings were shaken gently.

3. Chemical reaction of Na and K with H2O

75 cm3 H2O was poured into the conelike flask. Using the pincers, a little piece of the Na was put into the H2O. The experiment was repeated utilizing K.

Discussion

Table 1 shows clearly that ethyl alcohol and H2O were mixable. However, two beds occurred in H2O and hexane every bit good as in hexane and ethyl alcohol, which meant that they did non blend. Harmonizing to Lister and Renshaw ( 2000 ) , ethanol and H2O mix together because both of them have hydrogen bonds. Furthermore, Hexane and ethyl alcohols have weak new wave der Waals bonds, between the organic parts of each molecule. However, these forces are weak and they separate, so hexane and ethanol do mix. However, in our experiment hexane and ethyl alcohol produced bilayer, which means they are non mix successfully. Besides, hexane and H2O can non organize a mixture, because the hexane molecule is non polarized for good and can non organize H bond. To blend them together requires big sum of energy to interrupt hydrogen bonds, so H2O and hexane do non blend. ( Lister and Renshaw, 2000 )

In add-on, some solids can fade out in some liquids which have the similar composing. Table 2 indicates clearly that Cu sulfate dissolves in H2O while it did non fade out in the hexane. It is stated by Lister and Renshaw ( 2000:119 ) that “ ionic compounds can merely fade out good in polar liquids. ” Ionic bonds are present in Cu sulfate. Water is a polar liquid besides ionic, while hexane is a non-polar liquid. So the disintegration is sensible. It besides showed that iodine solution assorted with H2O, hexane and ethyl alcohol successfully. Iodine molecules can organize van der Waals attractive forces and do dissolves ill in polar dissolvers but good in non-polar dissolvers. ( Lister and Renshaw, 2000 ) .

The consequences show clearly that Na reacts strongly with H2O. Harmonizing to:

2Na ( s ) + 2H2O & A ; lt ; 2NaOH ( aq ) + H2 ( g )

Strongly alkalic Na hydrated oxide ( acerb sodium carbonate ) and H gas are made as the merchandises. During the procedure of let go ofing heat, H gas reacts strongly with the O, so it can fire with an orange fire. ( Lenntech, 2009 )

Besides, K is more reactive than Na, so it can respond more strongly with H2O.

Possible mistakes may hold arisen during the procedure of blending. First, the theory indicates that hexane can blend with ethyl alcohol. In fact, the consequence was different to the truth. Mistakes may hold arisen from the given ethyl alcohol which contains H2O. Since H2O can non fade out in the hexane, the bed occurred in our experiment. Second, It is non obvious to see that I dissolved in hexane successfully due to the coloring material alteration, which is a small different with the theory that iodine dissolves good in non-polar dissolvers. The disagreement may be as a consequence of utilizing the same pipette for adding H2O into a trial tubing. Hence, it might impact the hexane solution. Third, we can non see an orange fire during the trial of reaction of Na with H2O. It might stem from the pureness and the mass of Na. Third, the equipment were non clean plenty, which may do the consequence non precise. A future experiment should utilize different pipettes to absorb different solution. In add-on, it is good process to guarantee the pureness and mass of substance. Furthermore, the equipment should be clean plenty before making any trial.

Decision

Therefore it can be concluded that liquids can blend with liquids due to their similar

Intermolecular forces. Besides, liquids can blend with some solids which have the similar composing. Internet Explorer: CuSO4 and H2O are ionic ; I2 and hexane have van der waals attractive forces ; H2O and ethyl alcohol have hydrogen bond polar attractive forces. The active metal can respond strongly with H2O.

Mentions

• Lane, R ( 2009a ) IFY Chemistry Handouts Week 4 Chemistry Practical Guangzhou IFY Center
• Lane, R ( 2009b ) IFY category treatments Week 4 Chemistry Practical Guangzhou IFY Center
• Lenntech, 2009 [ Online ] Sodium ( Na ) and H2O Available at hypertext transfer protocol: //www.lenntech.com/periodic/water/sodium/sodium-and-water.htm ( Access day of the month 22/11/09 )
• Lister, T. and J. Renshaw ( 2000 ) Chemistry for Advanced Level ( 3rd edition ) . Cheltenham: Nelson Thornes Ltd