{{asɛmtiNe Ɔkyerɛwfo}} | Nhomakorabea | Nneɛma a ɛma wotumi yɛ ade

1

The process of reduction always involves...

losing oxygen.

gaining electrons.

losing electrons.

gaining protons.

1

When sodium chloride solution (NaCl(aq)) is electrolysed, which two substances are formed at the negative electrode (cathode)?

Sodium metal and chlorine gas

Hydrogen gas and sodium ions

Sodium metal and hydrogen gas

Hydrogen gas and hydroxide ions

1

When water is electrolysed, 20 cm³ of oxygen gas is collected. What volume of hydrogen gas would you expect to collect?

10 cm³

20 cm³

30 cm³

40 cm³

1

A student electrolyses molten lead(II) bromide, PbBr₂. What is produced at the positive electrode (anode)?

Lead metal

Hydrogen gas

Bromine gas

Oxygen gas

1

The reaction for the Haber process is: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ and the forward reaction is exothermic. What happens to the position of equilibrium if the pressure is increased?

It shifts to the left.

It shifts to the right.

There is no change.

The reaction stops.

1

Magnesium chloride has the formula MgCl₂. When it is electrolysed, a magnesium ion forms a magnesium atom by gaining two electrons. Which is the correct half equation?

$Mg^{2+} + 2e^- \rightarrow Mg$

$Mg \rightarrow Mg^{2+} + 2e^-$

$Mg^+ + e^- \rightarrow Mg$

$Cl_2 + 2e^- \rightarrow 2Cl^-$

1

In the reversible reaction $A + 2B \rightleftharpoons C$, what happens to the position of equilibrium if substance B is removed?

It shifts to the right to make more C.

There is no change.

It shifts to the left to make more B.

The rate of reaction increases.

1

What are the correct units for the relative formula mass (Mr)?

g

mol

g/mol

There are no units.

1

A sample of hydrated sodium carbonate, $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}$, is heated, and 3.6 g of water is produced. The Mr of $\text{H}_2\text{O}$ is 18. The Mr of $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}$ is 286. What mass of hydrated sodium carbonate was heated?

5.72 g

28.6 g

57.2 g

3.6 g

1

When electrolysing copper sulfate solution with inert electrodes, what is formed at the positive anode?

Copper metal

Sulfur

Oxygen gas

Hydrogen gas

1

A student electrolyses molten zinc chloride ($\text{ZnCl}_2$). What are the products at the negative cathode and positive anode?

Cathode: Hydrogen, Anode: Chlorine

Cathode: Zinc, Anode: Oxygen

Cathode: Zinc, Anode: Chlorine

Cathode: Hydrogen, Anode: Oxygen

1

The half-equation $\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}$ represents...

reduction because copper ions gain electrons.

reduction because copper metal loses electrons.

1

During the electrolysis of copper sulfate solution using copper electrodes, what happens to the mass of the anode and cathode?

Anode increases, Cathode decreases

Anode decreases, Cathode increases

Both increase

Both decrease

1

What are the essential components for an electrolytic cell?

Two electrodes and a solid electrolyte

A power supply, two electrodes, and an electrolyte

A power supply and a molten electrolyte

Two electrodes made of the same metal

1

A sample of hydrated magnesium sulfate, $ \text{MgSO}_4 \cdot 7\text{H}_2\text{O} $, has a mass of 24.6 g. It is heated to remove all the water. What mass of water is driven off? (Mr of $ \text{H}_2\text{O} = 18 $; Mr of $ \text{MgSO}_4 \cdot 7\text{H}_2\text{O} = 246 $)

1.8 g

12.6 g

18.0 g

24.6 g

1

In an electrolysis experiment, a student wants to produce the metal faster. What change should they make?

Use a catalyst

Use a higher current

Use smaller electrodes

Use a more dilute solution

1

What is the role of a catalyst in a reversible reaction?

It shifts the equilibrium to the right.

It increases the yield of the desired product.

It is used up during the reaction.

It increases the rate at which equilibrium is reached.

1

When electrolysing water, a small amount of sulfuric acid is added. Why?

To act as a catalyst.

To provide ions to carry the charge.

To colour the water.

To produce sulfur at the anode.

1

11.7 g of sodium chloride (NaCl) is dissolved in water. How many moles of NaCl is this? (Ar of Na = 23; Ar of Cl = 35.5)

0.1 moles

1

The equation for the decomposition of hydrogen peroxide is $2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)$. This reaction is often sped up with a manganese(IV) oxide catalyst. What is the role of the manganese(IV) oxide?

To increase the total volume of oxygen produced.

To increase the activation energy.

To provide an alternative reaction pathway with a lower activation energy.

To ensure the reaction goes to completion.

1

In the electrolysis of molten potassium iodide ($KI$), which statement is correct?

$K^+$ ions move to the anode and are oxidised.

$I^−$ ions move to the anode and are oxidised.

$K^+$ ions move to the cathode and are oxidised.

$I^−$ ions move to the cathode and are reduced.

1

Anhydrous copper(II) sulfate is white. Hydrated copper(II) sulfate is blue. The reversible reaction is: $CuSO_4(s) + 5H_2O(l) \rightleftharpoons CuSO_4 \cdot 5H_2O(s)$. The forward reaction is exothermic. What would you observe if you heated a sample of blue hydrated copper(II) sulfate?

It would stay blue.

It would turn white and steam would be produced.

It would turn white and no steam would be produced.

It would turn pink.

1

A student calculates that 0.05 moles of calcium carbonate ($CaCO_3$) should be produced in a reaction. What mass is this? (Ar of Ca = 40; C = 12; O = 16)

5.0 g

10.0 g

50 g

100 g

1

In the electrolysis of dilute sulfuric acid, why is the volume of gas at the cathode double the volume of gas at the anode?

Hydrogen atoms are smaller than oxygen atoms.

The formula for water is $H_2O$.

Hydrogen is less dense than oxygen.

Twice as many electrons are needed to make oxygen.

1

In the electrolysis of molten aluminium oxide ($Al_2O_3$), the carbon anodes need to be replaced frequently. Why is this?

The carbon reacts with the aluminium produced.

The carbon is brittle and breaks easily.

The high currents melt the carbon anodes.

The oxygen produced at the anode reacts with the carbon to form carbon dioxide.

1

25.0 cm³ of 0.20 mol/dm³ sodium hydroxide ($NaOH$) is neutralised by 20.0 cm³ of sulfuric acid ($H_2SO_4$). What is the concentration of the sulfuric acid? The equation is:

$2NaOH + H_2SO_4 \rightarrow Na_2SO_4 + 2H_2O$

0.125 mol/dm³

0.200 mol/dm³

0.250 mol/dm³

0.500 mol/dm³

1

Which of these is a correct definition of an electrolyte?

A substance that contains delocalised electrons.

A solid ionic compound that conducts electricity.

A substance that cannot be broken down by electricity.

A molten or dissolved ionic compound that conducts electricity.

1

A reversible reaction is allowed to reach equilibrium. What can be said about the rates of the forward and reverse reactions at this point?

The forward reaction has stopped.

The reverse reaction is faster than the forward reaction.

The forward and reverse reactions are occurring at the same rate.

The reverse reaction has stopped.

1

When electrolysing brine (concentrated $NaCl$ solution) in industry, three useful products are made. What are they?

Hydrogen, chlorine, and sodium hydroxide

Hydrogen, chlorine, and sodium

Oxygen, chlorine, and sodium

Hydrogen, oxygen, and sodium chloride

1

What is the relative formula mass (M_r) of calcium nitrate, $Ca(NO_3)_2$? (Ar of Ca = 40; N = 14; O = 16)

102

150

1

A 4.99 g sample of a hydrated salt, $ \text{CuSO}_4\cdot x\text{H}_2\text{O} $, is heated. The mass of the white anhydrous salt ($ \text{CuSO}_4 $) remaining is 3.19 g. Calculate the value of $ x $. (Mr of $ \text{H}_2\text{O} = 18 $; Mr of $ \text{CuSO}_4 = 159.5 $)

3

4

5

6

1

When copper sulfate solution ($ \text{CuSO}_4(\text{aq}) $) is electrolysed with inert electrodes, what is produced at the negative electrode (cathode)?

Copper metal

Hydrogen gas

Oxygen gas

Sulfur

1

For the same electrolysis of copper sulfate solution, what is produced at the positive electrode (anode)?

Copper metal

Hydroxide ions

Sulfur dioxide gas

Oxygen gas

1

The reaction for the Haber process is: $ \text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g}) $. The forward reaction is exothermic. What happens to the position of equilibrium if the temperature is increased?

It shifts to the left, favouring the reactants.

It shifts to the right, favouring the products.

There is no change in the position of equilibrium.

The reaction rate decreases.

1

For the same Haber process reaction, what is the effect of adding a catalyst?

It increases the yield of ammonia.

It shifts the equilibrium to the right.

It decreases the operating temperature of the reaction.

It increases the rate of both the forward and reverse reactions.

1

Which of these half-equations represents oxidation?

$ \text{Fe}^{3+} + \text{e}^- \rightarrow \text{Fe}^{2+} $

$ 2\text{H}^+ + 2\text{e}^- \rightarrow \text{H}_2 $

1

When electrolysing a dilute solution of sulfuric acid, what are the products at the anode and cathode?

Anode: Sulfur; Cathode: Hydrogen

Anode: Oxygen; Cathode: Hydrogen

Anode: Sulfur dioxide; Cathode: Water

Anode: Oxygen; Cathode: Water

1

Consider the equilibrium: $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$. What happens to the position of equilibrium if the concentration of $O_2$ is increased?

It shifts left to use up the extra $SO_3$.

It shifts right to use up the extra $O_2$.

There is no change.

The reaction stops.

1

A student has 0.25 moles of carbon dioxide ($CO_2$). What is the mass of this sample? (Ar of C = 12; O = 16)

7 g

11 g

22 g

44 g

1

Which of these statements correctly defines the anode?

It is the negative electrode where oxidation occurs.

It is the positive electrode where oxidation occurs.

It is the negative electrode where reduction occurs.

It is the positive electrode where reduction occurs.

1

A student electrolyses molten sodium chloride (NaCl). What are the products?

Sodium and Chlorine

Sodium and Oxygen

Hydrogen and Chlorine

Hydrogen and Oxygen

1

The same student now electrolyses a solution of sodium chloride (NaCl(aq)). What are the products at the cathode and anode?

Cathode: Sodium; Anode: Chlorine

Cathode: Hydrogen; Anode: Oxygen

Cathode: Sodium; Anode: Oxygen

Cathode: Hydrogen; Anode: Chlorine

1

Which half-equation shows a reduction reaction?

$Zn \rightarrow Zn^{2+} + 2e^{-}$

$2Br^{-} \rightarrow Br_{2} + 2e^{-}$

$Al^{3+} + 3e^{-} \rightarrow Al$

$2O^{2-} \rightarrow O_{2} + 4e^{-}$

1

The reaction used to make ethanol is: $C_{2}H_{4}(g) + H_{2}O(g) \rightleftharpoons C_{2}H_{5}OH(g)$. The forward reaction is exothermic. To get the best possible yield of ethanol, should the temperature be high or low?

High, to favour the endothermic reaction.

Low, to favour the exothermic reaction.

High, to increase the rate of reaction.

Low, to decrease the rate of reaction.

1

For the same ethanol reaction, $C_{2}H_{4}(g) + H_{2}O(g) \rightleftharpoons C_{2}H_{5}OH(g)$, what would be the effect of increasing the pressure?

The equilibrium would shift left.

The equilibrium would shift right.

There would be no effect on the equilibrium position.

The reaction would become more exothermic.

1

A student burns 1.2 g of carbon in plenty of air. What mass of carbon dioxide is formed? (Ar of C = 12; O = 16)

1.2 g

1

A sample of hydrated copper sulfate, $CuSO_4.5H_2O$, has a mass of 25.0 g. It is heated until all the water is removed. What mass of anhydrous copper sulfate ($CuSO_4$) remains? (Mr of $CuSO_4.5H_2O = 249.5$; Mr of $CuSO_4 = 159.5$)

9.0 g

16.0 g

18.0 g

25.0 g

1

During the electrolysis of an aqueous solution, which positive ion will be discharged at the cathode?

The more reactive ion.

The less reactive ion.

The ion with the bigger mass.

The ion with the higher charge.

1

What is the purpose of a catalyst?

To increase the amount of product formed.

To be used up in the reaction.

To increase the rate of a reaction.

To make a reaction more exothermic.

1

A 2.74 g sample of hydrated barium chloride, $BaCl_2 \cdot xH_2O$, is heated. After heating, the mass of the anhydrous salt is 2.34 g. What is the value of x? (Mr of $H_2O = 18$; Mr of $BaCl_2 = 208$)

A. 1

B. 2

C. 3

D. 4

1

In the Contact process, the reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$ is exothermic. The conditions used are 450 °C and 2 atm pressure. Why is a pressure of 2 atm used rather than a much higher pressure?

A. Because a high pressure would slow the reaction down.

B. Because the position of equilibrium is already very far to the right, so a high pressure is not needed and would be an unnecessary expense.

C. Because the catalyst only works at low pressure.

D. Because a low pressure favours the forward reaction.

1

During the electrolysis of dilute sodium nitrate solution ($NaNO_3(aq)$) with inert electrodes, what is produced at the anode?

A. Sodium metal

B. Nitrogen gas

C. Oxygen gas

D. Hydrogen gas

1

Calculate the volume of 1.5 mol/dm³ hydrochloric acid needed to completely react with 20 g of calcium carbonate ($CaCO_3$). (Mr of $CaCO_3 = 100$) $2HCl + CaCO_3 \rightarrow CaCl_2 + H_2O + CO_2$

A. 133 cm³

B. 200 cm³

C. 267 cm³

D. 400 cm³

1

What is observed when anhydrous copper(II) sulfate is added to water?

A. The solid dissolves to form a blue solution and the mixture gets hot.

B. The solid dissolves to form a blue solution and the mixture gets cold.

C. The solid dissolves to form a colourless solution and the mixture gets hot.

D. The solid does not dissolve.

1

In the electrolysis of molten lead(II) bromide ($PbBr_2$), which statement is true?

A. Lead ions are reduced at the anode.

B. Bromide ions are oxidised at the cathode.

1

A dynamic equilibrium is reached when...

the concentrations of reactants and products are equal.

the forward and reverse reactions have both stopped.

the rate of the forward reaction is equal to the rate of the reverse reaction.

all of the reactants have been converted to products.

1

In industry, ammonia is removed from the unreacted $N_2$ and $H_2$ gases by cooling and compressing the mixture. Why does this method work?

Because ammonia has a much higher boiling point than nitrogen and hydrogen.

Because ammonia is a catalyst for its own production.

Because ammonia is less dense than nitrogen and hydrogen.

Because only ammonia is magnetic.

1

What volume does one mole of any gas occupy at room temperature and pressure?

24 cm³

100 cm³

24 dm³

1 dm³

1

A student reacts excess magnesium with 50 cm³ of 0.5 mol/dm³ hydrochloric acid. What is the maximum volume of hydrogen gas that could be produced at room temperature and pressure?
$Mg + 2HCl \longrightarrow MgCl_2 + H_2$

300 cm³

600 cm³

1200 cm³

24000 cm³

Year 11 2025-2026 Post test consolidation

Year 11 2025-2026 Post test consolidation

The process of reduction always involves...

When sodium chloride solution (NaCl(aq)) is electrolysed, which two substances are formed at the negative electrode (cathode)?

When water is electrolysed, 20 cm3 of oxygen gas is collected. What volume of hydrogen gas would you expect to collect?

A student electrolyses molten lead(II) bromide, PbBr2. What is produced at the positive electrode (anode)?

The reaction for the Haber process is: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ and the forward reaction is exothermic. What happens to the position of equilibrium if the pressure is increased?

Magnesium chloride has the formula MgCl2. When it is electrolysed, a magnesium ion forms a magnesium atom by gaining two electrons. Which is the correct half equation?

In the reversible reaction $A + 2B \rightleftharpoons C$, what happens to the position of equilibrium if substance B is removed?

What are the correct units for the relative formula mass (Mr)?

A sample of hydrated sodium carbonate, $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}$, is heated, and 3.6 g of water is produced. The Mr of $\text{H}_2\text{O}$ is 18. The Mr of $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}$ is 286. What mass of hydrated sodium carbonate was heated?

When electrolysing copper sulfate solution with inert electrodes, what is formed at the positive anode?

A student electrolyses molten zinc chloride ($\text{ZnCl}_2$). What are the products at the negative cathode and positive anode?

The half-equation $\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}$ represents...

During the electrolysis of copper sulfate solution using copper electrodes, what happens to the mass of the anode and cathode?

What are the essential components for an electrolytic cell?

A sample of hydrated magnesium sulfate, $ \text{MgSO}_4 \cdot 7\text{H}_2\text{O} $, has a mass of 24.6 g. It is heated to remove all the water. What mass of water is driven off? (Mr of $ \text{H}_2\text{O} = 18 $; Mr of $ \text{MgSO}_4 \cdot 7\text{H}_2\text{O} = 246 $)

In an electrolysis experiment, a student wants to produce the metal faster. What change should they make?

What is the role of a catalyst in a reversible reaction?

When electrolysing water, a small amount of sulfuric acid is added. Why?

11.7 g of sodium chloride (NaCl) is dissolved in water. How many moles of NaCl is this? (Ar of Na = 23; Ar of Cl = 35.5)

The equation for the decomposition of hydrogen peroxide is $2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)$. This reaction is often sped up with a manganese(IV) oxide catalyst. What is the role of the manganese(IV) oxide?

In the electrolysis of molten potassium iodide ($KI$), which statement is correct?

Anhydrous copper(II) sulfate is white. Hydrated copper(II) sulfate is blue. The reversible reaction is: $CuSO_4(s) + 5H_2O(l) \rightleftharpoons CuSO_4 \cdot 5H_2O(s)$. The forward reaction is exothermic. What would you observe if you heated a sample of blue hydrated copper(II) sulfate?

A student calculates that 0.05 moles of calcium carbonate ($CaCO_3$) should be produced in a reaction. What mass is this? (Ar of Ca = 40; C = 12; O = 16)

In the electrolysis of dilute sulfuric acid, why is the volume of gas at the cathode double the volume of gas at the anode?

In the electrolysis of molten aluminium oxide ($Al_2O_3$), the carbon anodes need to be replaced frequently. Why is this?

25.0 cm3 of 0.20 mol/dm3 sodium hydroxide ($NaOH$) is neutralised by 20.0 cm3 of sulfuric acid ($H_2SO_4$). What is the concentration of the sulfuric acid? The equation is:$2NaOH + H_2SO_4 \rightarrow Na_2SO_4 + 2H_2O$

Which of these is a correct definition of an electrolyte?

A reversible reaction is allowed to reach equilibrium. What can be said about the rates of the forward and reverse reactions at this point?

When electrolysing brine (concentrated $NaCl$ solution) in industry, three useful products are made. What are they?

What is the relative formula mass (Mr) of calcium nitrate, $Ca(NO_3)_2$? (Ar of Ca = 40; N = 14; O = 16)

A 4.99 g sample of a hydrated salt, $ \text{CuSO}_4\cdot x\text{H}_2\text{O} $, is heated. The mass of the white anhydrous salt ($ \text{CuSO}_4 $) remaining is 3.19 g. Calculate the value of $ x $. (Mr of $ \text{H}_2\text{O} = 18 $; Mr of $ \text{CuSO}_4 = 159.5 $)

When copper sulfate solution ($ \text{CuSO}_4(\text{aq}) $) is electrolysed with inert electrodes, what is produced at the negative electrode (cathode)?

For the same electrolysis of copper sulfate solution, what is produced at the positive electrode (anode)?

The reaction for the Haber process is: $ \text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g}) $. The forward reaction is exothermic. What happens to the position of equilibrium if the temperature is increased?

For the same Haber process reaction, what is the effect of adding a catalyst?

Which of these half-equations represents oxidation?

When electrolysing a dilute solution of sulfuric acid, what are the products at the anode and cathode?

Consider the equilibrium: $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$. What happens to the position of equilibrium if the concentration of $O_2$ is increased?

A student has 0.25 moles of carbon dioxide ($CO_2$). What is the mass of this sample? (Ar of C = 12; O = 16)

Which of these statements correctly defines the anode?

A student electrolyses molten sodium chloride (NaCl). What are the products?

The same student now electrolyses a solution of sodium chloride (NaCl(aq)). What are the products at the cathode and anode?

Which half-equation shows a reduction reaction?

The reaction used to make ethanol is: $C_{2}H_{4}(g) + H_{2}O(g) \rightleftharpoons C_{2}H_{5}OH(g)$. The forward reaction is exothermic. To get the best possible yield of ethanol, should the temperature be high or low?

For the same ethanol reaction, $C_{2}H_{4}(g) + H_{2}O(g) \rightleftharpoons C_{2}H_{5}OH(g)$, what would be the effect of increasing the pressure?

A student burns 1.2 g of carbon in plenty of air. What mass of carbon dioxide is formed? (Ar of C = 12; O = 16)

A sample of hydrated copper sulfate, $CuSO_4.5H_2O$, has a mass of 25.0 g. It is heated until all the water is removed. What mass of anhydrous copper sulfate ($CuSO_4$) remains? (Mr of $CuSO_4.5H_2O = 249.5$; Mr of $CuSO_4 = 159.5$)

During the electrolysis of an aqueous solution, which positive ion will be discharged at the cathode?

What is the purpose of a catalyst?

A 2.74 g sample of hydrated barium chloride, $BaCl_2 \cdot xH_2O$, is heated. After heating, the mass of the anhydrous salt is 2.34 g. What is the value of x? (Mr of $H_2O = 18$; Mr of $BaCl_2 = 208$)

In the Contact process, the reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$ is exothermic. The conditions used are 450 °C and 2 atm pressure. Why is a pressure of 2 atm used rather than a much higher pressure?

During the electrolysis of dilute sodium nitrate solution ($NaNO_3(aq)$) with inert electrodes, what is produced at the anode?

Calculate the volume of 1.5 mol/dm3 hydrochloric acid needed to completely react with 20 g of calcium carbonate ($CaCO_3$). (Mr of $CaCO_3 = 100$) $2HCl + CaCO_3 \rightarrow CaCl_2 + H_2O + CO_2$

What is observed when anhydrous copper(II) sulfate is added to water?

In the electrolysis of molten lead(II) bromide ($PbBr_2$), which statement is true?

A dynamic equilibrium is reached when...

In industry, ammonia is removed from the unreacted $N_2$ and $H_2$ gases by cooling and compressing the mixture. Why does this method work?

What volume does one mole of any gas occupy at room temperature and pressure?

A student reacts excess magnesium with 50 cm³ of 0.5 mol/dm³ hydrochloric acid. What is the maximum volume of hydrogen gas that could be produced at room temperature and pressure?$Mg + 2HCl \longrightarrow MgCl_2 + H_2$

The process of reduction always involves...

When sodium chloride solution (NaCl(aq)) is electrolysed, which two substances are formed at the negative electrode (cathode)?

When water is electrolysed, 20 cm3 of oxygen gas is collected. What volume of hydrogen gas would you expect to collect?

A student electrolyses molten lead(II) bromide, PbBr2. What is produced at the positive electrode (anode)?

The reaction for the Haber process is: $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ and the forward reaction is exothermic. What happens to the position of equilibrium if the pressure is increased?

Magnesium chloride has the formula MgCl2. When it is electrolysed, a magnesium ion forms a magnesium atom by gaining two electrons. Which is the correct half equation?

In the reversible reaction $A + 2B \rightleftharpoons C$, what happens to the position of equilibrium if substance B is removed?

What are the correct units for the relative formula mass (Mr)?

A sample of hydrated sodium carbonate, $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}$, is heated, and 3.6 g of water is produced. The Mr of $\text{H}_2\text{O}$ is 18. The Mr of $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}$ is 286. What mass of hydrated sodium carbonate was heated?

When electrolysing copper sulfate solution with inert electrodes, what is formed at the positive anode?

A student electrolyses molten zinc chloride ($\text{ZnCl}_2$). What are the products at the negative cathode and positive anode?

The half-equation $\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}$ represents...

During the electrolysis of copper sulfate solution using copper electrodes, what happens to the mass of the anode and cathode?

What are the essential components for an electrolytic cell?

A sample of hydrated magnesium sulfate, $ \text{MgSO}_4 \cdot 7\text{H}_2\text{O} $, has a mass of 24.6 g. It is heated to remove all the water. What mass of water is driven off? (Mr of $ \text{H}_2\text{O} = 18 $; Mr of $ \text{MgSO}_4 \cdot 7\text{H}_2\text{O} = 246 $)

In an electrolysis experiment, a student wants to produce the metal faster. What change should they make?

What is the role of a catalyst in a reversible reaction?

When electrolysing water, a small amount of sulfuric acid is added. Why?

11.7 g of sodium chloride (NaCl) is dissolved in water. How many moles of NaCl is this? (Ar of Na = 23; Ar of Cl = 35.5)

When water is electrolysed, 20 cm³ of oxygen gas is collected. What volume of hydrogen gas would you expect to collect?

A student electrolyses molten lead(II) bromide, PbBr₂. What is produced at the positive electrode (anode)?

Magnesium chloride has the formula MgCl₂. When it is electrolysed, a magnesium ion forms a magnesium atom by gaining two electrons. Which is the correct half equation?

25.0 cm³ of 0.20 mol/dm³ sodium hydroxide ($NaOH$) is neutralised by 20.0 cm³ of sulfuric acid ($H_2SO_4$). What is the concentration of the sulfuric acid? The equation is:
$2NaOH + H_2SO_4 \rightarrow Na_2SO_4 + 2H_2O$

What is the relative formula mass (M_r) of calcium nitrate, $Ca(NO_3)_2$? (Ar of Ca = 40; N = 14; O = 16)

Calculate the volume of 1.5 mol/dm³ hydrochloric acid needed to completely react with 20 g of calcium carbonate ($CaCO_3$). (Mr of $CaCO_3 = 100$) $2HCl + CaCO_3 \rightarrow CaCl_2 + H_2O + CO_2$

A student reacts excess magnesium with 50 cm³ of 0.5 mol/dm³ hydrochloric acid. What is the maximum volume of hydrogen gas that could be produced at room temperature and pressure?
$Mg + 2HCl \longrightarrow MgCl_2 + H_2$

When water is electrolysed, 20 cm³ of oxygen gas is collected. What volume of hydrogen gas would you expect to collect?

A student electrolyses molten lead(II) bromide, PbBr₂. What is produced at the positive electrode (anode)?

Magnesium chloride has the formula MgCl₂. When it is electrolysed, a magnesium ion forms a magnesium atom by gaining two electrons. Which is the correct half equation?

25.0 cm³ of 0.20 mol/dm³ sodium hydroxide ($NaOH$) is neutralised by 20.0 cm³ of sulfuric acid ($H_2SO_4$). What is the concentration of the sulfuric acid? The equation is:
$2NaOH + H_2SO_4 \rightarrow Na_2SO_4 + 2H_2O$

What is the relative formula mass (M_r) of calcium nitrate, $Ca(NO_3)_2$? (Ar of Ca = 40; N = 14; O = 16)

Calculate the volume of 1.5 mol/dm³ hydrochloric acid needed to completely react with 20 g of calcium carbonate ($CaCO_3$). (Mr of $CaCO_3 = 100$) $2HCl + CaCO_3 \rightarrow CaCl_2 + H_2O + CO_2$

A student reacts excess magnesium with 50 cm³ of 0.5 mol/dm³ hydrochloric acid. What is the maximum volume of hydrogen gas that could be produced at room temperature and pressure?
$Mg + 2HCl \longrightarrow MgCl_2 + H_2$