WorksheetsPHS Edexcel Combined Science H Feb 2020 Chem Mock Revision 2
Total questions: 16
Worksheet time: 32mins
Magnesium and calcium are in group 2 of the periodic table. They are less reactive than the metals in group 1.
Calcium reacts with water to form calcium hydroxide, Ca(OH)2, and hydrogen, H2.
Ca(s) + 2H2O(l) → Ca(OH)2(s) + H2(g)
Describe what would be seen when a piece of calcium is dropped into a container of water
Hydrogen gas would be produced so would see bubbling.
Calcium moves around
A lilac flame
Calcium decreases in size
When zinc reacts with copper sulfate solution, zinc sulfate solution and copper are formed.
(i) An experiment was carried out to measure the temperature change when zinc powder reacts with copper sulfate solution.
initial temperature of copper sulfate solution = 20 °C
final temperature of mixture after the reaction = 46 °C
Explain what the temperature readings show about the type of heat change that occurs during this reaction.
The temperature increased, so the reaction is endothermic
The temperature increased, so the reaction is exothermic
The temperature decreased, so the reaction is endothermic
The temperature decreased, so the reaction is exothermic
Use the graph to explain how the rate of this reaction changes as the concentration of hydrochloric acid increases.
As the concentration of the hydrochloric acid decreases, the time taken to react decreases so the rate of reaction increases
As the concentration of the hydrochloric acid increases, the time taken to react increases so the rate of reaction increases
As the time increases the concentration of the hydrochloric acid decreases so the rate of reaction increases.
As the concentration of the hydrochloric acid increases, the time taken to react decreases so the rate of reaction increases
The dissolving of this solid in water is an exothermic change.
The experiment is repeated a number of times.
Compared with the initial temperature of the water, the final temperature of the solution is
always higher
always lower
sometimes higher sometimes lower
always unchanged
Lithium, sodium and potassium are reactive metals in group 1 of the periodic table.
In an experiment equal-sized pieces of lithium, sodium and potassium are added to separate samples of water.
A flame is produced only with potassium because potassium
Is the softest metal
has the lowest melting point
is the most reactive
is the only flammable metal
The electronic configurations of magnesium and calcium are
magnesium 2.8.2
calcium 2.8.8.2
When magnesium and calcium react with water they form positive ions.Suggest an explanation, in terms of their electronic configurations, why calcium is more reactive than magnesium.
In calcium the outer most electrons are further away from the nucleus therefore there is a stronger attraction between the nucleus and the electrons.
In calcium the inner most electrons are closer to the nucleus so there is a stronger attraction between the nucleus and the electrons.
In calcium the outer most electrons are further away from the nucleus therefore there is less attraction between the nucleus and the electrons.
A student poured 50 cm3 water into a beaker and measured the water's temperature.
The student added 1.00 g calcium chloride to the water, stirred the mixture and then recorded the temperature.
The student's results were
temperature of water at start = 21 °C
temperature of mixture after stirring = 32 °C
Explain, using these results, the type of heat energy change that occurs when calcium chloride dissolves in water.
The temperature increases as it is an exothermic process
The temperature increases as it is an endothermic process.
The reaction between calcium carbonate and dilute hydrochloric acid is exothermic.
Explain, in terms of bond breaking and bond making, why some reactions are exothermic.
Breaking bonds releases energy and is exothermic and making bonds needs energy and is endothermic. More energy is given out than is taken in.
Breaking bonds needs energy and is endothermic and making bonds releases energy and is exothermic. More energy is given out than is taken in.
When solid ammonium chloride is added to water a colourless solution is formed.
During the process the temperature of the liquid decreases.
Describe how you would measure the change in temperature.
Use a measuring cylinder to measure the volume.
Use a thermometer to measure the initial and final temperature
Use a thermometer to measure the final temperature
Use a set of weighing scales to measure the mass.
When solid ammonium chloride is shaken with water, a colourless solution forms and the temperature changes from 20°C to 16°C.
Give the name of the type of heat change occurring.
Endothermic
Exothermic
Biothermic
What type of chemical change causes a decrease in temperature?
Combustion
Endothermic
Exothermic
Neutralisation
Lithium, sodium and potassium are reactive metals in group 1 of the periodic table.
Explain, in terms of electronic configurations, the increase in reactivity from lithium to sodium to potassium.
As the atom becomes larger, the outer electrons get further away from the nucleus, the outer electron becomes easier to remove as there is a weaker force between the outer electrons and the nucleus.
As the atom becomes smaller the outer electrons get further away from the nucleus, the outer electron becomes easier to remove as there is a weaker force between the outer electrons and the nucleus.
As the atom becomes larger, the outer electrons get further away from the nucleus, the outer electron becomes harder to remove as there is a stronger force between the outer electrons and the nucleus.
As the atom becomes smaller, the outer electrons get closer to the nucleus, the outer electron then becomes easier to remove as there is a weaker force between the outer electrons and the nucleus.
A student used the equipment in Figure 6 to investigate the rate of reaction between zinc and excess dilute hydrochloric acid.
Give the name of a piece of equipment that can be used to measure 25 cm3 of dilute hydrochloric acid accurately.
Measuring cylinder
Beaker
Conical flask
Gas syringe
Use the results of these experiments to explain, in terms of the behaviour of particles, the effect of changing temperature and the effect of changing the concentration of A in solution on the rate of this reaction.
Increasing temperature increases the kinetic energy of the particles, as the particles move around more this increases the frequency of collisions so the reaction is faster.
Increasing the temperature decreases the time.
Increasing the concentration increases the number of particles in the same volume, therefore the frequency of collisions increases and the reaction is faster.
Increasing the concentration decreases the time.
Explain the meaning of catalyst.
A substance that speeds up a reaction by lowering the activation energy.
A substance that slows down a reaction.
A substance that does not get used up
A substance that speeds up a reaction without being used up.
Explain, in terms of collision of particles, how these results show the effect of the size of the lumps of calcium carbonate and the effect of the concentration of the acid on the rate of this reaction.
As the concentration increase volume of gas increases
As the lumps of carbonate get smaller the volume of gas decreases.
As the concentration increases, there are more particles in the same volume. This increases the collision frequency and increases the rate of reaction
A the lumps get smaller the surface area increases. This increases the collision frequency and increases the rate of reaction.
