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CHEMISTRY YEAR 8 EXAMS FOR END OF TERM 1

1.Here  are the formulae of SIX substances. Study them and answer questions that follow.

H2O

NaCl

CO2

N2

KOH

MgSO4

A. Name an element that occurs in 4 of these elements. [1]

……………………………………..

b. one of the substance is an element while the others are compounds. Which one? [1]

………………………………………………..

c. Name 3 metals present in the substances above. [3]

…………………………

…………………………

…………………………

d. Write the chemical symbols of the following atoms [10]

1. Hydrogen                             .……………..

2. Sodium                                ………………  

3. chlorine                               ….……………

4. Magnesium                         …………….…

5. carbon                                  ………………

6. nitrogen                               ………………

7. potassium                            ………………

8. sulfur                                   ………………

9. oxygen                                ……………….

10. calcium                              ………………

e. which compound is a hydroxide? [1]           ……………….

TERM-1 CHEM YEAR 8

f.  give the chemical name of the following substances. [not English names like water]

H2O [2]

   …………………………………..

NaCl [1]

   ………………………………….

CO2 [2]

   ………………………………….

N2    [1]

   ………………………………….

KOH [2]

    ………………………………….

MgSO[2]

     …………………………………..

CaCO3 [2]

     ………………………………….

2. give the meaning of the following terms

a. Atom[2]

……………………………………………………………………………………………………………………………………………………………………………..

b. Diffusion[2] ……………………………………………………………………………………………………………………………………………………………………………..

c. Brownian motion [2] ……………………………………………………………………………………………………………………………………………………………………………..

d. particles of gas X has a greater mass than that of Y. Which of the two gases diffuses faster. Explain.[2] ……………………………………………………………………………………………………………………………………………………………………………..

e. explain the effect of temperature on the rate of diffusion [3] …………………………………………………………………………………………………………………………………………………………………………….…………………………………………………………………………………………………………………………………………………………………………………

f. Liam carried out an experiment to investigate diffusion. He used water and food dye to investigate if volume of water affected time taken by the dye to spread through the water.

His prediction was that the more the water he used the longer the time take by the dye to spread out.

1. Which 2 variables did he keep constant? [2]

…………………………………………………………………………………………………………………………………………………………………………..…..

2. Which variable will he change [1]

…………………………………………………………………….

3. Which variable will he measure? [1]

………………………………………………………………….

4. How will he ensure that his results are reliable [1]

………………………………………………………………………………………………………………………………………………………………………………

5. Draw a suitable table that he will to show his results [2]

……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

6. Sketch a graph to show what the results will look like if his prediction is true [5]

……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

TERM-1 CHEM YEAR 8

2. Matter is made up of particles that are in a continuous state of motion. Describe how particles in the following move [3]

1. solids …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

2. Liquids

…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

3. gases

…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

3. Give 3 differences between solids and gases. [6]

solids Liquids
1………………………………………………………………     2………………………………………………………………     3……………………………………………………………… 1………………………………………………………………     2………………………………………………………………     3………………………………………………………………