Stogs GCSE Interleaving Calculations S

The diagram shows a molecule of paracetamol. Calculate its relative formula mass (M_r).

The balanced symbol equation for the reaction is: $Pb\left(NO_3\right)_2\left(aq\right)\ +\ 2NaI\left(aq\right)\ \rightarrow\ PbI_2\left(s\right)\ +\ 2NaNO_3\left(aq\right)$  
The student uses 2.4g of lead nitrate. The total mass at the end of the reaction is 3.9g. Calculate the mass of sodium iodide used.

What is the relative atomic mass of magnesium? The isotopes of magnesium and their percentage abundances are: ²⁴Mg 78.6%, ²⁵Mg 10.1%, ²⁶Mg 11.3%.

What is the mass of 0.1 moles of sulphur dioxide molecules, SO₂?

Calculate the number of moles of CH₄ molecules in 3.2 g of methane.

What is the empirical formula of a molecule made up of 1.44g carbon and 0.3g hydrogen?

• C₄H₁₀

• C₂H₅

• CH₂

• C₂H₁₀

What is the molecular formula of a molecule with empirical formula CH₂ and an M_r of 84.

• CH₂

• C₂H₄

• C₄H₈

• C₆H₁₂

Calculate the percentage yield for a reaction where the actual yield is 3.2 and the theoretical yield is 4.0g.

Calculate the atom economy for making iron in this reaction: $Fe_2O_3\ +3CO\ \rightarrow\ 2Fe\ +3CO_2$  

Zinc sulphate, ZnSO4, can be made by reacting zinc carbonate with sulphuric acid. Calculate the atom economy for making zinc sulphate in this way. $ZnCO_3\ +H_2SO_4\ \rightarrow\ ZnSO_4\ +H_2O\ +CO_2$