8 questions · 70 marks · ≈ 70 min
In this question the answer to each part is a number.
Give the pH value of a neutral solution.
Give a pH value of a weakly acidic solution.
Give the number of the Group in the Periodic Table that contains the elements that do not readily react.
Give the number of different elements present in glucose, C₆H₁₂O₆
The solubility of a solid depends on the solvent used.
State one other factor that affects the solubility.
A student wants to find the solubility of a salt in water. The steps in the student’s method are not in the correct order. Step A gently heat the evaporating basin and solution to remove all the water Step B filter to obtain 50.0 cm³ of saturated solution Step C record the mass of the evaporating basin and salt solution Step D record the mass of an empty evaporating basin Step E record the mass of the evaporating basin and the dry salt Step F put 50.0 cm³ of water into a beaker Step G add the salt to the water a little at a time and stir until no more dissolves Step H pour the 50.0 cm³ of saturated salt solution into the evaporating basin
The flowchart shows the correct order of some of the steps. Complete the flowchart by putting the remaining steps in the correct order. F B D E
These are the student’s results. mass of empty evaporating basin = 60.5 g mass of evaporating basin and dry salt = 78.1 g Calculate the solubility of the salt in grams per 100 g of water. [1.00 cm³ of water has a mass of 1.00 g] solubility = grams per 100 g of water
When 10.0 kg of a solid fuel is burned, the heat energy produced is 3.28 × 10⁵ kJ.
Calculate the heat energy, in kJ/mol, produced by the fuel. You should assume that the fuel is pure carbon. Give your answer to three significant figures. [for carbon, Ar = 12] heat energy = kJ/mol
The fuel actually contains some impurities, including sulfur. There is 600 g of sulfur in 20 kg of fuel.
Calculate the percentage of sulfur in the fuel. percentage of sulfur = %
When the fuel burns, the 600 g of sulfur produces sulfur dioxide gas. S + O₂ → SO₂ Calculate the volume, in cm³, of sulfur dioxide gas that would be produced at room temperature and pressure (rtp) when the fuel burns. [for a gas, molar volume = 24 dm³ at rtp] volume of sulfur dioxide = cm³
State the name of the environmental problem caused by sulfur dioxide in the atmosphere.
Hand sanitiser liquids are used regularly to reduce the spread of infections. Three compounds P, Q and R are often present in these liquids. P Q R H H H H H H CH₃CH₂OH H C C C O H H C C C H H H H H O H H
What type of formula is shown for P?
Choose your answer
a displayed formula
an empirical formula
a molecular formula
a structural formula
Compounds P, Q and R are members of the same homologous series. Give two properties of a homologous series. 1 2
Name the homologous series that contains compounds P, Q and R.
Give the name of compound Q.
Diols and dicarboxylic acids react together in polymerisation reactions to form polyesters.
Explain the name given to the type of polymerisation that occurs in these reactions.
Complete the equation for the polymerisation reaction by giving the displayed formula of the repeat unit of the polymer. ⎡ ⎤ ⎡ ⎤ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ H H H ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ n H O C C C O H ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ H H H ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎣ ⎦ ⎣ ⎦ n + + O O n H O C C O H 2n H₂O
This question is about the element phosphorus and some of its compounds.
The atomic number of phosphorus is 15 Give the electronic configuration of an atom of phosphorus.
Calcium phosphide is an ionic compound used in pest control. The formula of a calcium ion is Ca²⁺ Explain why the formula of calcium phosphide is Ca₃P₂
Calcium phosphide can be produced by heating calcium phosphate with carbon.
Complete the equation for the reaction. Ca₃(PO₄)₂ + C → Ca₃P₂ + CO
Explain the role of carbon in the reaction.
Calcium phosphide reacts with water to form calcium hydroxide and phosphine, PH₃ Give a chemical equation for this reaction.
Explain why calcium phosphide has a high melting point. You should refer to structure and bonding in your answer.
Iron metal was discovered several thousand years ago. Iron is produced industrially from iron(III) oxide by extraction using carbon. Sodium is a metal in Group 1 of the Periodic Table. Sodium was discovered by Sir Humphrey Davy in 1807. It is produced industrially by the electrolysis of sodium chloride.
Explain, using the reactivity series, why carbon can be used to extract iron from iron(III) oxide.
Suggest why sodium was not discovered until 1807.
The diagram shows a simplified version of the Downs cell, which can be used to produce sodium industrially. The electrolyte is molten sodium chloride. sodium chloride added chlorine gas electrolyte molten sodium steel cathode steel cathode carbon anode
Explain why the molten electrolyte conducts electricity.
What is the formula of the cation in the electrolyte?
Choose your answer
H⁺
Cl⁻
Na⁺
OH⁻
During the production of sodium, small explosions can be heard. Explain why using sodium chloride that is not completely dry could cause these small explosions.
Give ionic half-equations for the reactions at the anode and cathode. anode cathode
Explain why the reactivity of metals in Group 1 increases from lithium to potassium.
A student is asked to find the concentration of a solution of nitric acid by doing a titration. The student is provided with sodium hydroxide solution with a concentration of 0.350 mol/dm³ These are the first four steps in the student’s method.
Give the reason for using the white tile.
Universal indicator is not a suitable indicator to use in a titration. Complete the table to show the name of a suitable indicator and its final colour in this titration. Indicator Final colour in titration
The student wants to obtain an accurate value for the volume of sodium hydroxide solution needed to neutralise the 25.0 cm³ of nitric acid. Describe all the further steps the student should take.
This is a summary of the student’s results. volume of HNO₃ used = 25.0 cm³ concentration of NaOH solution = 0.350 mol/dm³ volume of NaOH solution needed for neutralisation = 18.80 cm³ The equation for the reaction is HNO₃ + NaOH → NaNO₃ + H₂O
Calculate the amount, in moles, of NaOH that reacts. amount of NaOH = mol
Determine the amount, in moles, of HNO₃ that reacts. amount of HNO₃ = mol
Calculate the concentration, in mol/dm³, of the HNO₃ concentration = mol/dm³
This question is about reactions involving nitrogen.
In a car engine, nitrogen reacts with oxygen to form nitrogen monoxide. The equation for the reaction is N₂ + O₂ → 2NO ΔH = +181 kJ Draw a labelled reaction profile diagram showing ΔH and the activation energy for the reaction. Energy
In the Haber process, nitrogen reacts with hydrogen to form ammonia. This equation represents the reaction. N N + 3H H → 2H N H H The table gives values of some bond energies. Bond Bond energy in kJ/mol N N 944 H H 436 N H 391
Calculate the total amount of energy, in kJ, needed to break the bonds in the reactants. energy needed = kJ
Calculate the total amount of energy, in kJ, released in forming the bonds in the product. energy released = kJ
Calculate the enthalpy change, ΔH , for the reaction. You should include a sign in your answer. ΔH = kJ