The following data are needed for this question.

∆H_f^Ɵ (CO(g)) = –111 kJ mol^-1

∆H_f^Ɵ (CO­₂(g)) = –394 kJ mol^-1

∆H_f^Ɵ (Fe₂O₃(s)) = –822 kJ mol^-1

Carbon monoxide reacts with iron(III) oxide.

3CO(g) + Fe₂O₃(s) → 3CO₂(g) + 2Fe(s)

What is the enthalpy change when 55.8 g of iron are produced by this reaction?

Copper reacts with dilute nitric acid to produce nitrogen dioxide gas. The balanced ionic equation is given.

Cu + 2H⁺ + 2HNO₃ --> Cu²⁺ + 2NO₂ + 2H₂O

Which of the following is correct?

Which of the following will occur in the cell shown ?

The table shows the successive ionisation energies for an element X.

What could be the formula of the fluoride of X ?

X, Y and Z are elements in Period 3 of the Periodic Table.

A mixture containing the oxides of X, Y and Z was dissolved in excess dilute sulfuric acid and filtered. The oxide of Z was collected as a residue. When excess dilute sodium hydroxide was added to the filtrate, only a white precipitate of the hydroxide of Y was formed.

What are the possible identities of X, Y and Z?

Samples of magnesium carbonate, MgCO₃, are placed in crucibles R and S.

The sample in crucible R is heated until there is no further loss in mass, and then allowed to cool.

The sample in crucible S is left unheated.

Dilute hydrochloric acid is then added to both crucibles.

On adding the dilute hydrochloric acid, which observations are correct?

In the reaction shown, M represents a Group 2 element.

MO₂ → MO + ½ O₂

Which statement about this reaction is correct?

In the preparation of silicon, silicon dioxide is heated with magnesium.

SiO₂ + 2Mg --> 2MgO + Si

The product mixture contains MgO and Si only. To separate the silicon from the product mixture, students proposed the following two possible methods :

1. Shake the mixture with aqueous hydrochloric acid and filter.

2. Heat the mixture gently and collect the evaporated silicon.

Which methods would work?

Germanium is between silicon and tin in Group 14. Which one of the following statements about germanium chemistry is least likely to be true?

A type of silicate has the structure like shown in the diagram.

Which of the following is true about the above structure ?

I It can be found in amphiboles

II Its anion is Si ₄O₁₁^6-

III the mineral with the above structure is asbestos

For elements in Group 17 of the Periodic Table, which of the following statements is true as the group is descended?

The highest oxidation state of chlorine is present in

When concentrated sulfuric acid reacts with sodium iodide the products include sulfur, iodine, hydrogen sulfide and sulfur dioxide.

Which statement is correct?

The electron configuration of chromium in CrO₄^2- ion is