Embed Size (px)
Citation preview
Moulsham High School 1
Level 6 Chemistry Questions
1. Rema used the apparatus below to distil 100 cm3 of water-soluble ink.
apparatus A
not to scale
(a) Which processes occur during distillation? Tick the correct box.
condensation then evaporation
evaporation then condensation
melting then boiling
melting then evaporation
1 mark
(b) Give the name of the colourless liquid that collects in the test-tube.
.....................................................
1 mark
(c) What would the temperature reading be on the thermometer when the ink has been boiling for two minutes?
..............°C
1 mark
Moulsham High School 2
(d) (i) Water at 15°C enters the condenser at X.
Predict the temperature of the water when it leaves the condenser at Y.
..............°C
Explain this change of temperature.
.............................................................................................................
.............................................................................................................
1 mark
(ii) Give two ways in which the water vapour changes as it passes down the glass tube in the condenser.
1. .........................................................................................................
1 mark
2. .........................................................................................................
1 mark
(e) Peter used the apparatus below to distil 100 cm3 of water-soluble ink.
apparatus B
not to scale
Why is the condenser in apparatus A better than the glass tube and beaker of water in apparatus B?
......................................................................................................................
......................................................................................................................
1 mark
maximum 7 marks
Moulsham High School 3
2. (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.
greater than less than the same as
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
Moulsham High School 4
(c) Zeena pushes the lid down and nitrogen gas escapes through the diaphragm.
The diaphragm vibrates and produces a sound.
The pattern on the oscilloscope screen below represents the soundwave produced by the alarm.
(i) The loudness of the sound produced by the alarm decreases between X and Y.
How can you tell this from the graph?
.............................................................................................................
.............................................................................................................
1 mark
(ii) The pitch of the sound produced by the alarm stays the same between X and Y.
How can you tell this from the graph?
.............................................................................................................
.............................................................................................................
1 mark
maximum 5 marks
Moulsham High School 5
3. A scientist compared the acidity of four gases to see which gas might cause acid rain.
She used four balloons to collect the gases. She then bubbled the gases, in turn, through a fresh sample of green, neutral, universal indicator solution.
rubbertube
balloon containinggas
universal indicatorsolution
(a) Three of the gases caused the indicator to change colour. The scientist added drops of alkali to the indicator until the indicator changed back to green. Her results are shown in the table below.
gases collected
change in colour of indicator
number of drops of alkali needed to change the indicator back to green
exhaust gases from a car
green to red 31
carbon dioxide green to red 160
air no change 0
human breath green to yellow 10
Use information in the table to answer part (i) and part (ii) below.
(i) Which gas dissolved to form the most acidic solution?
...........................................................
Explain your choice.
.............................................................................................................
.............................................................................................................
1 mark
Moulsham High School 6
(ii) Which gas formed a neutral solution?
...........................................................
Explain your choice.
.............................................................................................................
.............................................................................................................
1 mark
(iii) What effect does an alkali have on an acid?
.............................................................................................................
1 mark
(b) Some metals react with acids in the air. Complete the word equation for the reaction between zinc and hydrochloric acid.
zinc + hydrochloric → ........................................ + ........................................ acid
2 marks
maximum 5 marks
4. Alan put a test-tube containing solid stearic acid into a beaker of cold water. He heated the water until it boiled.
to data-logger
temperature sensor
watersolid stearic acid at the start
electric hotplate
Moulsham High School 7
He used a temperature sensor attached to a data-logger to record the temperature
of the stearic acid over a period of 35 minutes. A graph of the results is shown below.
temperatureof stearicacid (°C)
100
90
80
70
60
50
40
30
200 5 10 15 20 25 30 35
time (minutes)
A
B C
D
Stearic acid is a solid at room temperature.
(a) (i) Which letter on the graph opposite shows the point at which the stearic acid began to change state?
...............
1 mark
(ii) Use the graph to find the temperature at which the stearic acid began to change state.
............... °C
1 mark
(iii) Look at the graph. What was the physical state of the stearic acid:
at point A? ...........................................................
at point D? ...........................................................
2 marks
Moulsham High School 8
(b) The test-tube transfers thermal energy from the water to the stearic acid.
By what method is most of the thermal energy transferred? Tick the correct box.
conduction evaporation
convection radiation
1 mark
(c) Stearic acid boils at 360°C. The stearic acid could not boil in this experiment. Give the reason for this.
.....................................................................................................................
.....................................................................................................................
1 mark
maximum 6 marks
5. Some pupils predicted that water will evaporate faster if the surrounding air temperature is higher.
To investigate their prediction they placed some water in containers in two different rooms.
(a) Give two factors they should keep the same to make their investigation fair.
1. ..................................................................................................................
1 mark
2. ..................................................................................................................
1 mark
Moulsham High School 9
(b) They recorded the mass of the water and the container in room 1 and room 2
every day for 5 days.
The table below shows their results.
time mass of water and container (g)
(days) room 1 room 2
0 100 100
1 92 85
2 80 72
3 72 54
4 60 45
5 46 30
The data shown in their table is not sufficient to test their prediction. Explain why.
.....................................................................................................................
.....................................................................................................................
1 mark
They plotted their data for room 2 and attempted to draw a line of best fit.
100
90
80
70
60
50
40
30
mass ofwater andcontainer(g)
0 1 2 3 4 5 6 7time (days)
Moulsham High School 10
(c) Describe the mistake they made in drawing the line of best fit.
.....................................................................................................................
.....................................................................................................................
1 mark
(d) Using the data in the table plot the points for room 1.
1 mark
(e) Draw a line of best fit of the points you have drawn.
1 mark
(f) In which room did the water evaporate more quickly? Tick one box.
room 1 room 2
Use their data to explain your answer.
.....................................................................................................................
.....................................................................................................................
1 mark
maximum 7 marks
6. Hydrochloric acid is a strong acid.
(a) Winston used universal indicator solution to find the pH of some hydrochloric acid.
(i) Suggest the colour of the mixture of universal indicator solution and the hydrochloric acid.
...........................................................
1 mark
(ii) Suggest the pH of the hydrochloric acid.
...............
1 mark
Moulsham High School 11
(b) Indigestion can be caused when too much hydrochloric acid is produced in the
stomach. Magnesium carbonate can be used to treat indigestion.
Winston crushed some indigestion tablets containing magnesium carbonate. He added them to hydrochloric acid in a test-tube. The mixture fizzed.
hydrochloric acid
crushed indigestiontablet
The word equation for the reaction is shown below.
magnesium + hydrochloric → magnesium + carbon + water carbonate acid chloride dioxide
(i) Use the word equation to explain why the mixture fizzed when the reaction took place.
.............................................................................................................
.............................................................................................................
1 mark
(ii) Winston continued to add crushed tablets to the acid until the mixture stopped fizzing. Why did the fizzing stop?
.............................................................................................................
.............................................................................................................
1 mark
Moulsham High School 12
(c) When magnesium carbonate reacts with hydrochloric acid, magnesium chloride is
formed.
Which two words describe magnesium chloride? Tick the two correct boxes.
a compound
a mixture
an element
a salt
a metal
a solvent
2 marks
(d) It is important that the hydrochloric acid in the stomach is not completely neutralised by indigestion tablets.
Why is hydrochloric acid needed in the stomach?
.....................................................................................................................
.....................................................................................................................
1 mark
maximum 7 marks
7. Shuli investigated differences between physical and chemical changes.
She put three chemicals in separate crucibles and weighed each one. She heated each crucible as shown below. She weighed each crucible again when it had cooled down.
Moulsham High School 13
She recorded her observations in a table as shown below.
experiment name of chemical observations change in mass
A magnesium (a silvery solid)
The silvery magnesium burned brightly in air. A white powder was
formed.
increase
B potassium permanganate
(purple crystals)
The purple crystals crackled and turned black.
A colourless gas was given off.
decrease
C zinc oxide (a white powder)
The white powder turned pale yellow on heating. It turned white again on
cooling.
no change
(a) (i) In experiment A, magnesium reacts with a gas in the air.
Complete the word equation for the reaction in experiment A.
magnesium + ..................................... → ...................................................
2 marks
(ii) Explain the increase in mass in experiment A. Use your word equation to help you.
.............................................................................................................
.............................................................................................................
1 mark
(b) The gas given off in experiment B re-lit a glowing splint. Give the name of this gas.
................................................................
1 mark
(c) Name the white powder left at the end of experiment C.
..................................................................
1 mark
Moulsham High School 14
(d) In each experiment, did a chemical change or a physical change take place?
Tick one box for each experiment.
experiment chemical change physical change
A
B
C
1 mark
Maximum 6 marks
8. (a) Methane can be a gas, a liquid or a solid. In the diagram below, arrows P, Q, R and S represent changes of state.
The boxes on the right show the arrangement of particles of methane in the three different physical states. Each circle represents a particle of methane.
gas
liquid
solid
P Q
R S
physical state of methane arrangement of particles
(i) Draw a line from each physical state of methane to the arrangement of particles in that physical state. Draw only three lines.
1 mark
Moulsham High School 15
(ii) Arrows P, Q, R and S represent changes of state.
Which arrow represents:
evaporation? ............................................................
melting? ...................................................................
2 marks
(b) Methane is the main compound in natural gas. The scale below shows the melting point and the boiling point of methane.
–200 –160 –80 –60 –40 –20 0–180 –140 –120 –100
meltingpoint
–183°C
boilingpoint–162 °C
°C
Methane has three physical states: solid, liquid and gas.
(i) What is the physical state of methane at –170°C?
.............................................................
1 mark
(ii) The formula of methane is CH4. The symbols for the two elements in methane are C and H.
Give the names of these two elements.
element C .............................................
element H ............................................
2 marks
(iii) When methane burns, it reacts with oxygen. One of the products is water, H2O.
Give the name of the other product.
..............................................................
1 mark
Maximum 7 marks
Moulsham High School 16
9. Sarah and Jim investigated the effect of temperature on the solubility of copper
sulphate.
They dissolved copper sulphate crystals in the same volume of water until no more would dissolve. This means the solution was saturated. They measured the mass of copper sulphate needed to make a saturated solution using water at different temperatures.
They plotted their results on a grid.
60
50
40
30
20
1030 40 50 60 70 80
temperature of water, in °C
mass of dissolvedcopper sulphatecrystals, in g
(a) (i) One of the mass readings appears to be wrong (anomalous).
Circle the anomalous result on the graph.
1 mark
(ii) Draw a smooth curve of best fit on the graph.
1 mark
Moulsham High School 17
(iii) Use the graph to predict a more likely measurement of mass for the
anomalous result.
..................... g
1 mark
(b) Suggest one mistake Sarah might have made to produce this anomalous result.
.....................................................................................................................
.....................................................................................................................
1 mark
Maximum 4 marks
