Predict how many grams of CaCl2 can be produced from 15.00 grams of KCl

Question

Using this balanced equation: CaCO3 + 2KCl → CaCl2 + K2CO3

Predict how many grams of CaCl2 can be produced from 15.00 grams of KCl

Answer 1

When given grams, we want to first convert to moles, and then back to grams at the end.

CaCO₃ + 2KCl ==> CaCl₂ + K₂CO₃ ... balanced equation

................15.00 g........?g..................

molar mass of KCl = 74.55 g/mol

molar mass CaCl₂ = 110.98 g/mol

moles KCl present = 15.00 g KCl x 1 mol KCl / 74.55 g = 0.2012 moles

moles of CaCl₂ formed = 0.2012 moles KCl x 1 mol CaCl₂ / 2 moles KCl = 0.1006 moles

grams CaCl₂ formed = 0.1006 moles CaCl₂ x 110.98 g/mol = 11.16 g (4 sig. figs.)

Using dimensional analysis to obtain the final result, we have...

15.00 g KCl x 1 mol KCl/74.55 g x 1 mol CaCl₂ / 2 mol KCl x 110.98 g CaCl₂/mol CaCl₂ = 11.16 g CaCl₂