Chemistry 9701 · AS & A Level · 3.2

3.2 — practice question

When heated, both magnesium nitrate, $\text{Mg(NO}_3\text{)}_2$, and strontium nitrate, $\text{Sr(NO}_3\text{)}_2$, break down to produce the metal oxide and a mixture of gases.
(a)[1]

Write the equation for the thermal decomposition of $\text{Mg(NO}_3\text{)}_2$.

(b)[2]

State which of $\text{Mg(NO}_3\text{)}_2$ or $\text{Sr(NO}_3\text{)}_2$ decomposes at the lower temperature. Explain your answer.

(c(i))[1]

Magnesium oxide, $\text{MgO}$, and strontium oxide, $\text{SrO}$, both react with dilute sulfuric acid. $\text{MgO}$ gives a soluble salt, A. $\text{SrO}$ gives an insoluble salt, B. Identify the products formed when $\text{MgO}$ reacts with dilute sulfuric acid.

(c(ii))[3]

Explain why A has a higher solubility than B.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: The equation is Mg(NO3)2 → MgO + 2NO2 + ½O2 OR 2Mg(NO3)2 → 2MgO + 4NO2 + O2

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI