Practice Paper 2 (SL IB Chemistry)

Using your knowledge of atomic structure, complete the table below for the particles found in an atom. 

The actual mass of protons, neutrons and electrons is given.

Calculate the mass, in g, of a nitrogen molecule.

Oxygen consists of three stable isotopes, oxygen-16, oxygen-17, and oxygen-18.

State the particles present in each isotope and outline what differences would be expected in the chemical reactivity of the three isotopes.

Suggest why some elements have several isotopes and others, like fluorine, have only one known isotope (known as monoisotopic elements).

Predict whether phosphorus(V) oxide and sodium oxide conduct electricity in their solid and molten states. Complete the boxes with “yes” or “no”.

State the formula of the compounds formed between the elements below.

i)    Sodium and sulfur.

[1]

ii)    Magnesium and phosphorus.

[1]

Describe the covalent bond present in a chlorine molecule and how it is formed.

Draw the Lewis (electron dot) structure of chloromethane.

The following dynamic equilibrium was reached at temperature, T, in a closed container.

2X (g) + Y (g) ⇌ 2Z (g)             ΔH = -65 kJ mol^-1

The value of K_c for the reaction was 75.0 mol^-1 dm³ when the equilibrium mixture contained 2.97 mol of Y and 5.38 mol of Z.

If the conditions for a closed container are changed, it can affect the concentrations of the reactants, products and K_c. 

State the effect, if any, on the concentration of Y at equilibrium if temperature, T, is decreased and give a reason for your answer.

Calculate the equilibrium constant for the following reaction at temperature, T. 

2Z (g) ⇌ 2X (g) + Y (g)

The first ionisation energy for all the elements is found in Section 9 of the IB data booklet.

The graph below in Figure 1 shows some information on the elements of period 3 of the periodic table.

Figure 1

State and explain the trend that this graph shows, including why there are values that deviate from the trend.

Draw and name all the possible isomers of C₆H₁₄.

Figure 1 below shows a three-dimensional structure of a molecule.                                                  

Figure 1 

A teacher instructs a class to complete a calorimetry practical, to calculate the enthalpy change that occurs when hydrochloric acid and sodium hydroxide react together.  

Each student was given roughly 60 cm³ of 0.35 mol dm^-3 hydrochloric acid, roughly 60 cm³ of 0.35 mol dm^-3 sodium hydroxide, a polystyrene cup and access to all standard laboratory equipment.

Draw a diagram to demonstrate the practical set up that the students would need to use to determine the enthalpy change during this neutralisation reaction, and state the key measurements that the students would have to make.

The students then completed the practical from part (a), using their own method and measurements that they had chosen.

One student found that when they reacted 35.0 cm³ of the hydrochloric acid with 35.0 cm³ of the sodium hydroxide, the temperature rose from 19.6 ^oC to 22.3 ^oC.

Determine the enthalpy change, ΔH, for this reaction in kJ mol^-1. Assume that both solutions have a density of 1.00 g cm^-3 and a specific heat capacity of 4.18 J g^-1 K^-1.