Calculate how many moles of SrF2 will be produced from 5.5 moles of HF in the following reaction. Sr(OH) 2 + 2 HF 4 SrF2 + 2 H2O

Question

a. 2.75 moles SrF2 0

b. 11 moles SrF2

c. 7.5 moles SrF2

d. 5.5 moles SrF2

Answer 1

A balanced chemical reaction is important for a couple reasons:

1. It obeys conservation, meaning nothing is created/destroyed over the course of the reaction.
2. Its coefficients tell us molar ratios of each species. For example, 1 mole of Sr(OH)₂ requires 2 moles of HF to produce 1 mole of SrF₂ and 2 moles of H₂O.

For the balanced reaction, I got Sr(OH)₂ + 2HF → SrF₂ + 2H₂O.

This means that 2 moles of HF should produce 1 mole of SrF₂. However, 5.5 moles of HF is more than the 2 moles given in the balanced reaction, so we'd predict that more than 1 mole of SrF2 is produced.

More precisely:

5.5 mol HF * (1 mol SrF₂/2 mol HF) = 2.75 mol SrF₂.