Unit 7G (Particle Model of Solids, Liquids and Gases) and Unit 7H (Solutions)

Unit 7G (Particle model of solids, liquids and gases) and Unit 7H (Solutions)

Question No. / Level / Mark / Question No. / Level / Mark
1(97) / 4 / 4 / 9(97) / 5 / 5
2(99) / 4 / 5 / 10(95) / 5 / 8
3(99) / 4 / 6 / 11(01) / 5 / 6
4(03) / 4 / 5 / 12(97) / 6 / 8
5(97) / 4 / 5 / 13(95) / 6 / 7
6(05) / 4 / 8 / 14(05) / 6 / 5
7(05) / 4 / 6 / 15(03) / 6 / 4
8(05) / 5 / 5

1. (a) Complete the following sentence.

When a solid dissolves in a solvent, a ...... is formed.

1 mark

A beaker contains water. It is on a balance.
The balance reads 200.0 g.
Patti adds 10.5 g of salt to the water. The salt dissolves.

(b) When all the salt has dissolved, what is the reading on the balance?

...... g

Describe how she could do this.

......

2 marks

Maximum 4 marks

2. John dropped a glass bottle of blue copper sulphate crystals. The bottle broke and glass was mixed with the crystals.

(a) Suggest how John or a teacher could clear up the mixture safely, without cuttingthemselves.

......

1 mark

(b) Mari said, “You can separate the glass from the copper sulphate crystals usingasieve”.

Most of the crystals went through the sieve. Some of the glass went through as well.

Why did some of the crystals and pieces of glass stay in the sieve?

......

1 mark

(c) John tried another way to separate the glass from the blue copper sulphate crystals. He put the mixture into water and stirred it.
The water turned blue. Why did the water turn blue?

......

1 mark

(d) Very carefully, he poured some of the blue liquid into a dish and gently heated it. The volume of the liquid decreased.
Why did the volume decrease?

......

1 mark

(e) John put the dish by a window. The next day there was no liquid left.
What would be left in the dish?

......

1 mark

Maximum 5 marks

3. Emma dissolved some salt in some water to make salt water.

(a) Which words in the list below describe the salt, the water and the salt water?

Write the correct words in the table.

3 marks

solution solute sediment filtrate solvent

(b) What two things could Emma do to make the salt dissolve more quickly?

1......

2......

2 marks

(c) Emma dissolved 5 g of salt in 50 cm3 of water. Now she wants to make some salt water which is only half as concentrated.

What should she do? Tick the correct box.

1 mark

Maximum 6 marks

4. Diagrams A, B and C show three pieces of apparatus for separating substances.

(a) Draw a line from each apparatus to the name of the method of separation.
Draw only three lines.

diagram of apparatus method of separation

3 marks

(b) Debbie has a mixture of sand and salt water.
Look at the diagrams in part (a).

(i) Which apparatus would Debbie use to separate the sand from the salt water?
Give the correct letter.

......

1 mark

(ii) Which apparatus would she use to separate pure water from the salt water?
Give the correct letter.

......

1 mark

Maximum 5 marks

5. Becky puts one tea bag in a beaker and adds 50 cm3 of warm water. She stirs the liquid slowly. Every 15 seconds she takes out 2 cm3 of the liquid and measures how dark it is.

(a) Which graph, A, B or C, shows how the colour of the liquid changes?

......

1 mark

(b) (i) Becky takes out 2 cm3 samples of the liquid each time. Why must she always put the sample back after she has tested it?

......

1 mark

(ii) What piece of apparatus can she use to measure the volume of the 2 cm3 samples of liquid?

......

1 mark

(iii) Suggest two ways Becky could make the tea dissolve more quickly.

1 ......

......

2 ......

......

2 marks

Maximum 5 marks

6. Emma and Philip wanted to see if changing the temperature of the water affected the time taken for a cold cure powder to dissolve in water.

Philip recorded their results.

(a) (i) Write the heading for the first column in the table below.

...... (ºC) / time to dissolve (s)

(ii) Write their results correctly in the table above.

3 marks

(b) Give the names of two pieces of measuring equipment they would need.

1......

1 mark

2......

1 mark

......

1 mark

(d) Emma wrote, ‘My investigation was good’, as her conclusion.

Philip said this was not a scientific conclusion.

Explain why Emma’s conclusion is not scientific.

......

1 mark

(e) Look at their results above.

Write a scientific conclusion for their investigation.

......

1 mark

maximum 8 marks

7. (a) Ruth added some blue copper sulphate crystals to a beaker of water.

(i) How could Ruth see that some of the copper sulphate crystals had dissolved in the water?

......

1 mark

(ii) How could Ruth make the copper sulphate crystals dissolve more quickly?

......

1 mark

(b) Ruth poured some of the copper sulphate solution into a dish.
She left it in a warm room for five days.

All the water evaporated from the solution in the dish.
What was left in the dish?

......

1 mark

(c) Ruth did an experiment to see how much of three solids, P, Q and R, will dissolve in water at different temperatures.
She plotted her results on graph paper as shown below.

Use the graph above to answer the questions below.

(i) At 30°C how many grams of solid R dissolved in the water?

...... g

1 mark

(ii) At 60°C which solid dissolved the most in water? Give the letter.

......

1 mark

(iii) Which two solids were equally soluble at 25°C? Give the letters.

...... and ......

1 mark

maximum 6 marks

8. Two groups of pupils investigated the factors affecting the time taken for an indigestion tablet to dissolve in 100 cm3 of water.

Group 1 recorded their results in the table below.

results of group 1

tablet / time taken to dissolve (s)
whole tablet / 34
broken tablet / 28
finely crushed tablet / 22

(a) What factor did group 1 change as they carried out their investigation?

......

1 mark

(b) Before the investigation, group 1 made a prediction.
They found this prediction was supported by the results in the table.

What prediction did group 1 make?

......

1 mark

Here are their results.

results of group 2

temperature of water (ºC) / time taken to dissolve (s)
65 / 24
40 / 35
15 / 90
5 / 100

What factor did group 2 change as they carried out their investigation?

......

1 mark

(d) What pattern do the results recorded by group 2 show?

......

1 mark

(e) Look at the results presented by group 1 and group 2.

Both groups used the same type of tablet.

Estimate the temperature of water used by group 1.

...... °C

1 mark

maximum 5 marks

9. A scientist investigates the paints used in oil paintings. She takes tiny pieces of yellow, blue and green paint and tries to dissolve them in different solvents.
Her results are shown in the table.

(a) Which solvent does not dissolve the blue paint?

......

1 mark

She then uses chromatography to investigate the paints.

(b) Only one of the solvents in the table will make all three paints move up the chromatography paper. Which solvent is this?

......

1 mark

(c) The scientist then investigates the paint used in three different oil paintings. She takes tiny pieces of yellow, blue and green paint from each picture and uses chromatography to compare them.

Her results are shown below:

Which of the paints in the 1993 picture contains only one substance?
Tick the correct box.

yellow, Y blue, B green, G

1 mark

The scientist decides that picture 3 is probably recent and not from around 1625.

(d) Look at the chromatography results for the three pictures. Explain how the scientist was able to decide this.

......

2 marks

Maximum 5 marks

10. This question is about three different fuels, A, B and C.

Fuel A is stored in tanks. It is not stored under pressure. It flows along a pipe to where it is needed.

Fuel B is stored under pressure in small cylinders. It is used by campers.

Fuel C can be stored in sacks or bags.

(a) (i) Tick the correct box.

Fuel A is a:

solid

liquid

gas

1 mark

Name a fuel which A could be ......

1 mark

(ii) Tick the correct box.

When fuel B comes out of the cylinder this is a:

solid

liquid

gas

1 mark

Name a fuel which B could be ......

1 mark

(iii) Tick the correct box.

Fuel C is a:

solid

liquid

gas

1 mark

Name a fuel which C could be ......

1 mark

(b) Complete the statement to describe what happens when a fuel burns.

Two waste products formed from burning fuels are

...... and ......

2 marks

Maximum 8 marks

11. Cathy has two orange drinks, X and Y. She uses chromatography to identify the coloured substances in the drinks. Her experiment is shown below.

Cathy made the chromatogram below using drink X, three food colourings, E102, E160, E110,and drink Y.

(a) (i) Use Cathy’s chromatogram to identify the two coloured substances in drink X.
Write their E numbers below.

1. …………………..…………………………

2. …………………………………….……….

2 marks

(ii) Draw another spot on Cathy’s chromatogram to show what it would look like ifdrinkY contained E102 as well.

1 mark

(iii) Chromatography separates the coloured substances in a drink.
How can you tell from a chromatogram how many coloured substances thereareina drink?

..……………………………………………………………………………….

1 mark

(b) (i) The spots show up well on filter paper. Give one other reason why filter paperisused in this experiment.

..……………………………………………………………………………….

1 mark

(ii) The line across the bottom of a chromatogram should be drawn with a pencil,notwith ink.
Why should the line not be drawn with ink?

..……………………………………………………………………………….

1 mark

Maximum 6 marks

12. This question is about four chemical elements.

(a) The melting points and boiling points of the four elements are shown in the table. Complete the table to give the physical state, solid, liquid or gas, of each element at room temperature, 21°C.

element / melting point
in °C / boiling point
in °C / physical state at room
temperature, 21°C
bromine / –7 / 59
chlorine / –101 / –34
fluorine / –220 / –188
iodine / 114 / 184

4 marks

(b) Bromine can be a solid, a liquid or a gas depending on the temperature.
In which physical state will 10 g of bromine store the most thermal energy?

......

1 mark

(i) far apart and random? ......

1 mark

(ii) close together but random? ......

1 mark

(iii) close together in a regular pattern? ......

1 mark

Maximum 8 marks

13. The following diagrams show two methods of separating substances.

(a) What is the name of each method?

Method 1 is ......

1 mark

Method 2 is ......

1 mark

(b) (i) Tick one box to show which of the mixtures can be separated by method 1.

sugar and salt

sand and water

dissolved salt and water

sand and iron filings

sugar and salt, both dissolved in water

1 mark

(ii) From the list give a mixture which can be separated by method 2 but not by method 1.

......

1 mark

(i) A purple ink is a dissolved mixture of the red dye and the blue dye. On the right of the diagram draw the pattern you would expect to see for purple ink.

1 mark

(ii) Which three inks contain only one dye?

......

1 mark

(iii) What colour is spot X?

......

1 mark

Maximum 7 marks

14. (a) (i) Air contains nitrogen.
In the box below draw five circles, , to show the arrangement of particles in nitrogen gas.

1 mark

(ii) Zeena carries a personal emergency alarm.
It uses nitrogen gas to produce a very loud sound.

The nitrogen gas in the container is under much higher pressure than the nitrogen gas in the air.

How does the arrangement of nitrogen particles change when the gas is under higher pressure?

......

1 mark

(b) Use words from the boxes below to complete the sentence.

The rate at which the nitrogen particles hit the inside of the container is ...... the rate at which nitrogen particles hit the outside of the container.

1 mark

(c) Zeena pushes the lid down and nitrogen gas escapes through the diaphragm.
The diaphragm vibrates and produces a sound.