How many grams of solute are needed to make 125 mL of 2.50 M NH4Cl solution? Round to three significant digits.

Mass = 16.7 g

Explanation:

Given dа ta:

Volume = 125 mL (125/1000 = 0.125 L)

Molarity = 2.50 M

Mass in grams of solute = ?

Solution:

First of all we will calculate the number of moles:

Molarity = number of moles solute / volume in litter

2.50 M = Number of moles of solute / 0.125 L

Number of moles of solute = 2.50 M * 0.125 L

Number of moles of solute = 0.313 mol

Grams of solute:

Number of moles = mass / molar mass

Mass = number of moles * molar mass

Mass = 0.313 mol * 53.5 g/mol

Mass = 16.7 g