Question

How many grams of Cl are in 535 g of CaCl₂?

Answer 1

The answer is 341.7 g.

(1) Calculate the molar mass (M) of CaCl2 which is the sum of atomic masses (A) of elements:
M(CaCl2) = A(Ca) + 2A(Cl)
A(Ca) = 40.1 g/mol
A(Cl) = 35.45 g/mol

M(CaCl2) = 40.1 + 2 * 35.45 = 40.1 + 70.9 = 111 g/mol

(2) Calculate in how many moles are 535 g:
M(CaCl2) = 111 g/mol
111g : 1mol = 535 g : xmol
x = 535 g * 1mol : 111g = 4.82 mol

(3) Calculate how many grams of Cl are in 4.82 mol:
A(Cl) = 35.45 g/mol 
2A(Cl) = 2 * 35.45 = 70.9 g/mol
70.9 g : 1 mol = x : 4.82 mol
x = 70.9 g * 4.82 mol : 1 mol = 341.7 g