What is the mass of Cl in 21 g of NaCl?

1 Answer
Nov 7, 2015

12.78g

Explanation:

21g of NaCl is equivalent to 0.36mol.

Na (atomic mass = 23 g/mol), Cl (atomic mass = 35.5g/mol)

Mole = ("Atomic Mass") ("Molar Mass")

Total molar mass of NaCl = 23 + 35.5 = 58.5 g/mol

Mole = 21 cancel g NaCl x "1 mol"/ (58.5 cancel g) NaCl = 0.36 mol NaCl

1 mol of NaCl consists of 1 mol of Na ion and 1 mol of Cl ion

or

NaCl rarr Na^+ + Cl^-

Therefore, 0.36mol of NaCl is equal to 0.36mol of Cl.

Mass of Cl = (Mole Cl) (Atomic Mass Cl)

Mass of Cl = 0.36 "mol Cl" x "35 g"/ (1 cancel "mol") Cl

Mass of Cl = 12.78g Cl