Home › WAEC WASSCE › Chemistry › Stoichiometry of Chemical Reactions › For (NH4)2SO4 + Ca(OH)2 giving 2NH3 + CaSO4 + 2H…
For (NH4)2SO4 + Ca(OH)2 giving 2NH3 + CaSO4 + 2H2O, how many moles of NH3 come from 4.0 mol of Ca(OH)2?
A2.0 mol
B4.0 mol
C8.0 mol
D16 mol
Answer & Solution
Correct answer: C. 8.0 mol
1. The equation shows 2 mol NH3 for every 1 mol Ca(OH)2.
2. The factor is therefore 2 mol NH3 per 1 mol Ca(OH)2.
3. Multiply: 4.0 mol times 2, which gives 8.0 mol NH3.
4. Halving instead of doubling would give 2.0 mol, which reverses the factor.
5. Multiplying that 8.0 mol by the number of particles per mole gives the molecule count.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 4 "Stoichiometry of Chemical Reactions", section 4.3 Reaction Stoichiometry_
Related questions
In the reaction between sodium and chlorine, sodium is oxidised, which means chlorine:Ordering the three ways of writing a reaction from most to least detail about ions gives:When one element appears in more than one formula on the same side of an equation, you musWhen balancing a combustion equation, an odd number of oxygen atoms on the product side isCompounds that produce hydroxide ions by chemically reacting with water, rather than by diA double arrow is used in an acid equation to indicate that the acid is:A neutralisation reaction has an acid and a base as reactants and typically produces:Sodium hydroxide is classified as a strong base because in water it: