Question
The elements shown are gases at room temperature and pressure.
hydrogen
nitrogen
oxygen
chlorine
(a) State which one of these gases is green.
(b) The gases shown exist as diatomic molecules.
State the name of another element which has diatomic molecules and is a gas at room
temperature and pressure.
(c) When separate samples of each of these gases are placed in a container they will diffuse.
(i) Describe why these gases diffuse.
(ii) State which of these four gases has the highest rate of diffusion.
Explain your answer.
gas ……………………………………………………………………………………………………………………..
explanation ………………………………………………………………………………………………………….
(d) Nitrogen, oxygen and other substances are found in clean, dry air.
(i) State the percentage of nitrogen in clean, dry air.
(ii) Other than nitrogen and oxygen, identify another element found in clean, dry air.
(iii) Identify a compound found in clean, dry air.
(iv) Nitrogen and oxygen can be separated from liquid air.
State the name of this process.
Answer/Explanation
Answer:
(a) chlorine
(b) fluorine
(c) (i) random motion of molecules/particles
(ii) hydrogen
lowest (relative) molecular mass
(d) (i) 78
(ii) argon/Ar
(iv) fractional (1)
distillation (1)
Question
This question is about solids, liquids and gases.
(a) The list gives the names of nine substances which are solids at room temperature.
a ceramic
aluminum
anhydrous cobalt(II) chloride
anhydrous copper(II) sulfate
calcium oxide
graphite
iodine
iron
sodium
Answer the following questions about these substances.
Each substance may be used once, more than once or not at all.
State which substance:
(i) turns pink when water is added to it[1]
(ii) is a non-metal which is used as a lubricant[1]
(iii) is used to neutralize acidic industrial waste[1]
(iv) is extracted from bauxite[1]
(v) is used as an electrical insulator.[1]
(b) Some changes of state of sodium are shown.
(i) State the names of the changes of state represented by A and B.[2]
A
B
(ii) Use the kinetic particle model to describe the arrangement and separation of the particles in:
solid sodium
liquid sodium [4][Total: 11]
Answer/Explanation
Ans:
(a)(i) (anhydrous) cobalt chloride
(a)(ii) graphite
(a)(iii) calcium oxide
(a)(iv) aluminum
(a)(v) ceramic
(b)(i) A: melting (1)
B: condensing / condensation (1)
(b)(ii) solid:
particles arranged regularly / particles ordered (1)
particles touching / particles close together (1)
liquid:
particles arranged irregularly / particles randomly arranged (1)
particles close together / particles touching (1)
Question
A student left a cube of ice on a plate in a warm room. The diagrams below show what happened
to the ice.
(a) Describe and explain what happened to the ice. In your answer,
• describe and explain the change of state which occurs,
• explain this change using the kinetic particle theory.
(b) Water is used in industry and in the home.
(i) Give one use of water in industry.
(ii) Give one use of water in the home.
(c) The symbol equation for the reaction of lithium with water is shown below.
\(2Li(s) + 2H_2O(l) → 2LiOH(aq) + H_2(g)\)
(i) Write the word equation for this reaction.
(ii) Describe two observations which can be made when lithium reacts with water.
(iii) Describe how the reactivity of potassium with water compares with the reactivity of lithium
with water.
(d) Ethanol can be made by the reaction of steam with ethene.
(i) Draw the structure of ethene showing all atoms and all bonds.
(ii) Describe the conditions required for this reaction.
(e) The table below describes the reaction of water or steam with different metals.
Answer/Explanation
Answer:
(a) melting/ ice melts / ice goes from solid to liquid;
any four from:
• in solid particles regularly arranged;
• in solid particles arranged in fixed position / cannot move;
• particles in solid absorb energy;
• particles (in solid) vibrate more / particles start to move when heated;
• forces between particles (in solid) broken;
• particles in liquid slide over each other / move;
• particles in liquid not regularly arranged;
(b) (i) coolant / for making ethanol / for making specified chemicals / solvent;
(ii) washing/ cooking/ cleaning etc.;
(c) (i) lithium + water → lithium hydroxide + hydrogen;
(ii) any two from:
• floats on surface (of water);
• bubbles of gas;
• fizzes / fizzing sound;
• decreases in size / disappears;
• moves around;
(iii) (potassium) more reactive / lithium less reactive;
(d) (i) correct structure of ethene;
(ii) high temperature;
catalyst/ phosphoric acid;
(e) cobalt → iron → cerium → calcium;
one pair reversed or all reversed = [1]