Ankit Gola Class:- XII E Roll No:-

Study of diffusio n of solids in liquids

CERTIFICATE

This is certified that Ankit Gola oF Class XII-E , ROLL NOhas successfully completed his Project STUDY OF Diffusion of solids in liquids himself and under my guidance. The progress of the project has been continuously reported and has been in my knowledge consistently. Mr. Sushil Joshi ( PGT , CHEMISTRY ) (Rajkiya Pratibha Vikas Vidyalaya, Civil lines)

ACKNOWLEDGEMENT

It gives me great pleasure to express my gratitude towards our chemistry teacher Mr. Sushil Joshi for his guidance, support and encouragement throughout duration of the project. Without his motivation the successful completion of this project would not have been possible.

I am very thankful to my teacher, who allows me to work at my convenience under his estimate guidance.

Ankit Gola XII E Roll No.

Index Aim Introduction Objective

Experiment 1 Experiment 2 Experiment 3 Experiment 4 Result

IntroductionWhen substances are brought in contact with each other, they intermix. This property of intermixing is known as diffusion. This property of diffusion takes place very rapidly in case of gases and to a lesser extent in case of liquids whereas solids do not show this process of diffusion with each

other. But what we can observe in case of solids is that the diffusion of solids in liquids takes place at a very slow rate. If a solid is kept in contact with an excess of solvent in which it is soluble, some portion of the solid starts dissolving. After some time a stage reaches when whole of the solid gets dissolved. We know that this process is known as dissolution of the solid in a liquid and this process has taken place due to the diffusion of solid particles into the liquid. Molecules of solutes in solutions are in constant random motion due to the collisions between molecules of solute and that of the solvent. Also as the temperature is raised, kinetic energy of molecules increases which thereby increases the number of collisions. Particles of different substances move at different rates e.g., when different coloured inks are placed in water at constant temperature, they diffuse at different rates. The speed of the movement of solid particles depends upon (a) Temperature (b) Size of the particles (c) Mass of the particle.

AIM

Study of diffusion of solids in liquids.

OBJECTIVE OF PROJECT

Rate of diffusion depends upon three factors viz. (i) temperature, (ii) size of particles and (iii) mass of particle. In this project, we aim at illustrating these facts experimentally by taking crystals of copper sulphate, potassium permanganate and ammonium dichromate.

EXPERIMENT -1

AIM :- To study diffusion when copper sulphate (solid) is broughtin contact with water (liquids).

Requirements :- Copper sulphate crystal, 100 ml beaker.

Procedure :1. Take about 2gm of copper sulphate crystals in 100 ml beaker. 2. Add about 50 ml of water and allow to stand for few minutes. 3. Note the development of blue colour in water.4.

Allow to stand further when it will be observed that whole of the copper sulphate disappears.

Conclusions :When solids such as copper sulphate, potassium permanganate are brought in contact with liquids such as water, intermixing of the substances, i.e., diffusion takes place.

EXPERIMENT 2

Aim :-

To study the effect of particle size on the rate of diffusion of solids in liquids.

Requirements :Graduated 100 ml measuring cylinders, copper sulphate crystals of different sizes, stop watch.

Procedure :1. 2. 3. 4. Add 50 ml of water to each of the three cylinders. Take 5.0 g each of water to each of the three cylinders. Allow to stand for sometime. Note the time taken for the blue colour to reach any fixed mark in each of the cylinders and record the observations.

100 90 80 70 60 50 40 30 20 10 Big CuSO4 crystal

100 90 80 70 60 50 40 30 20 10 Medium CuSO4 crystal

100 90 80 70 60 50 40 30 20 10 Small CuSO4 crystal

0

(I)

0

(II)

0

(III)

Observations :S. No. I II III Crystal Size Big Medium Small Time taken in minute 21 15 06

Conclusions :Small particles undergo diffusion more quicker than bigger particles.

EXPERIMENT - 3

Aim :-

To study upward rate of diffusion of solids having different molecular mass.

Requirements :Crystals of copper sulphate and potassium dichromate.

Procedure :1. Take two 100 ml graduated cylinders and fill each with 50 ml distilled water. 2. Place a crystal of copper sulphate and a crystal of potassium dichromate (~1 gm each) separately in two cylinders. 3. Note the time taken for the colours to reach any fixed mark in each of the following cylinders and record the observations.

100 90 80 70 60 50 40 30 20 10 Copper sulphate Crystal Potassium dichromate Crystal

100 90 80 70 60 50 40 30 20 10

0

0

Observations :Room temperature Molecular mass of CuSO4.5H2O Molecular mass of K2Cr2O7 Molecular mass of Cu2+ ion Molecular mass of Cr2O72- ion S. No. Crystal type I Copper sulphate II Potassium dichromate = 27oC = 249.5 g/mol = 294 g/mol = 63.5 g/mol = 216 g/mol Time taken in minutes 04 11

Conclusion :The rate of diffusion of copper sulphate is approximately three times the rate of diffusion of potassium dichromate, but the ratio of the molecular masses of K2Cr2O7 to

that of CuSO4.5H2O is (294/249.5) 1.2 . It is concluded that the rate of the rate of diffusion of the two salts are not inversely proportional to their molecular masses but inversely proportional to the molecular masses of the coloured ions i-e. Cu2+ (63.5 g/mole) and Cr2O72- (216 g/mole). So it is observed that if the molecular masses of the coloured ion is high , then the rate of upward diffusion is low provided water remains undisturbed at constant temperature. Other factors which affect the experimental results but have not been considered here are charge on the ions and effect of other ions such as SO42- and K+.

EXPERIMENT 4

Aim :-

To study the effect of temperature on the rate of diffusion of solids in liquids.

Requirements :Copper sulphate crystals, 200 ml beakers, watch glass, wire gauge, burner, tripod stand, thermometer and stop watch.

Procedure :1. 2. 3. 4. 5. Take 5 gm of copper sulphate each in three 200 ml beakers. Pour 100 ml of distilled water slowly in o0ne of the beakers. Cover this beaker with the watch glass. Pour 100 ml of cold water in a second beaker slowly. Place the third beaker containing 100 ml of water on a tripod stand for heating

6. Observe the diffusion process which begins in all the three beakers. 7. Record the time taken for the dissolution of copper sulphate in all the three cases.

Water (25oC)

CuSO4 Crystal

Water (10oC)

CuSO4 Crystal

Water (70oC)

Observations :S. No. I II III Temperature of water 25 oC 10 oC 70 oC Time taken in minute 11 17 05

Conclusions :The rate of diffusion of copper sulphate in water is in the order of Beaker III > Beaker I > Beaker II. Thus, rate of diffusion varies directly with temperature.

Results

Solid particles and undergo diffusion when they come in contact with liquids.

Small particles undergo diffusion more quickly than bigger particles. When solids such as copper sulphate, potassium permanganate are brought in contact with liquid such as water, intermixing of the substances, i.e. diffusion takes place. The rate of diffusion varies directly with temperature.