A chemist adds of a M zinc nitrate solution to a reaction flask. Calculate the mass in grams of zinc nitrate the chemist has added to the flask. Round your answer to significant digits.

corrected question: A chemist adds 135mL of a 0.21M zinc nitrate solution to a reaction flask. Calculate the mass in grams of zinc nitrate the chemist has added to the flask. Round your answer to significant digits.

Answer:

5.37g

Explanation:

0.21M means; 0.21mol/dm³

1dm³=1L, so we can say 0.21mol/L

if 0.21mol of Zinc nitrate is contained in 1L of water

x will be contained in 135mL of water

x = 0.21*135*10³/1

=0.02835moles

number of moles = mass / molar mass

mass = number of moles * molar mas

molar mass of Zn (NO₃) ₂=189.36 g/mol

mass = 0.02835 * 189.36

mass=5.37g