Practice Paper 1A (HL IB Chemistry)

The reaction shown occurs in gas clouds throughout the Universe.

H₂ (g) + H₂⁺ (g) → H (g) + H₃⁺ (g)

Which is the correct atomic structure of the H₃⁺ ion?

What is the electronic configuration of an ion with a single negative charge and atomic number 17?

A compound contains carbon and hydrogen only. The amount of carbon is 80% by mass. What is the empirical formula of the compound?

                                             (RAMs, H = 1.01, C = 12.01)

A 5370 cm³ sample of oxygen is measured at a temperature of 60°C. The pressure measured was 103,000 Pa.

Assume the gas behaves as an ideal gas.

What is the mass of the sample of oxygen?

What is the correct formula for aluminium sulfate?

In acidic conditions, ammonia, NH₃, reacts with a proton, H⁺, to form ammonium NH₄⁺.

Using the following key:

    N electron

   H electron

Which of the following Dot & Cross diagrams correctly illustrate electron movement in this reaction.

Below are four molecules. Which is the most polar molecule present?

Which of the following structures do not obey the octet rule?

1. BeCl₂
2. BF₃
3. H₂O

Which is the shortest bond length in the following gases?

Which statement about metals is correct?

Plastics made from this polyester, with the following repeat unit, only soften at high temperatures.

Which statement correctly explains the reason for this?

Non-metallic elements in the p block can have the following two properties:

• property 1: atoms with no paired electrons in 3p
• property 2: have an oxide that can form a strong acid in water

Which properties do phosphorus and sulfur have? 

Bromine exists as two isotopes ⁷⁹Br and ⁸¹Br, which are found in almost equal abundance. 

Which of the following statements is correct?

The first ionisation energies and reactions with water for sodium and caesium are compared below.

Which set of statements, comparing sodium and caesium, are correct?

An element Z has the same oxidation state as a common iron ion but the Z ion has the same number of electrons as Ne . An oxide of element Z reacts with a strong acid to produce a chloride salt but does not dissolve in water.

What is the correct identity of element Z?

What is the whole number coefficient for oxygen when the equation for the combustion of pentanol is balanced?

C₅H₁₁OH(g) + O₂  → CO₂(g) + H₂O(g)

Which alcohol is likely to have a fragment ion at m/e = 31 in its mass spectrum?

The diagram shows an infrared spectrum of a compound.

Which compound would give this spectrum?

The table below discusses three types of enthalpy change:

‘+’ means that this type of standard enthalpy change can only have positive values,

‘–’ means that this type of standard enthalpy change can only have negative values,

‘+ / –’ means that either positive or negative values are possible. 

Which row is correct?

Propanone has the molecular formula C₃H₆O. Use the following information to calculate the enthalpy change for the formation of propanone? 

The enthalpy change of combustion of carbon is x kJ mol ^-1

The enthalpy change of combustion of hydrogen is y kJ mol ^-1

The enthalpy change of combustion of propanone is z kJ mol ^-1

Which of the following products are possible from the incomplete combustion of alkanes?

   C

II.    CO

H₂

Combustion of ethene proceeds via the reaction shown in the Hess cycle diagram.

 What are the correct elements missing from the Hess cycle?

Which statements are correct for the following reaction?

1.   The reaction will be feasible at high temperatures 
2.   The reaction will never be feasible 
3.   The reaction becomes more disordered

When heated, anhydrous magnesium nitrate, Mg(NO₃)₂, will decompose into magnesium oxide and a mixture of gases shown in the following equation

2Mg(NO₃)₂ (s) → 2MgO (s) + 4NO₂ (g) + O₂ (g)

1.48 g of anhydrous magnesium nitrate is heated until no further reaction takes place.

What mass of nitrogen dioxide is produced?

The diagram below represents, for a given temperature, the Boltzmann distribution of the kinetic energy of the molecules in a mixture of two gases that react slowly together without a catalyst.

The activation energy for the reaction, E_a, is marked for the uncatalysed reaction

What would the position of E_a be if the reaction took place with an effective catalyst?

Four possible energy profiles are shown below, for reactions carried out at the same temperature.

Which energy profile shows a reaction that is likely to proceed most rapidly and with a good yield?

For the following reaction at equilibrium

H₂S (aq)  +  Mg²⁺ (aq)  ⇋   MgS (s)   +  2H⁺ (aq)              ΔH < 0

Which of the following changes will result in more MgS being produced?

A beaker containing 100 cm³ of 2M sulfuric acid, H₂SO₄ (aq), was placed on a balance and then an excess of powdered zinc was added. The change in mass was recorded against time and the results plotted on a graph as shown in line I below.

What change in conditions could result in line II shown on the graph?

When a chemical reaction reaches equilibrium which of the following can be said about the concentrations of the substances present, and the rates of reaction?

The diagram shows a Boltzmann distribution of molecular energies for a gaseous mixture. The distribution has a peak, labelled Q on the diagram.

What happens when an effective catalyst is added to the mixture?

What role does each species play in the equilibrium below according to Brønsted-Lowry theory?

CH₃COOH + HCl  ⇌ CH₃COOH₂⁺ + Cl^-

What is the sum of the coefficients when the following acid-base equation is balanced?

_Al₂(CO₃)₃ (s) + _HNO₃ (aq)  ⇌ _Al(NO₃)₃ (aq) + _H₂O (l) +  _CO₂ (g)

When sulfuric acid and sodium iodide react, one of the reactions that takes place is shown by the equation below: 

            8NaI  +  9H₂SO₄  →  8NaHSO₄  +  4I₂  +  H₂S  +  4H₂O 

Which species has been oxidised in this reaction?

The following reaction can be used to determine the mass of titanium dioxide in an ore. 

            3TiO₂  +  4BrF₃  →  3TiF₄  +  2Br₂  +  3O₂ 

Which element increases in oxidation number in this reaction?

Ethane reacts with bromine in the presence of ultraviolet light to form tribromoethane and hydrogen bromide.

The reaction proceeds via free radical substitution involving initiation, propagation and termination steps.

Which equation represents a possible termination step in this reaction?

Which reaction is an example of nucleophilic substitution?

In which complexes does iron have an oxidation state of +3? 

1.   [Fe(H₂O)₆]³⁺
2.   [Fe(H₂O)₅(CN)]²⁺
3.   [Fe(CN)₆]³⁻

Consider the following equation

AgCl + 2NH₃→ [Ag(NH₃)₂]⁺ + Cl^-

Which of the following statements is correct?

Which molecule can react with both sodium borohydride, NaBH₄, and warm acidified potassium dichromate(VI)?