Question

if 2.03 g of CuNO3 is dissolved in water to make a 0.110 M solution, what is the volume of the solution?

What is the concentration of a solution made by diluting 25 mL of 6.0 M HCl to a final volume of 750 mL?

Answer 1

1)

Molar mass of CuNO3,

MM = 1*MM(Cu) + 1*MM(N) + 3*MM(O)

= 1*63.55 + 1*14.01 + 3*16.0

= 125.56 g/mol

mass(CuNO3)= 2.03 g

use:

number of mol of CuNO3,

n = mass of CuNO3/molar mass of CuNO3

=(2.03 g)/(1.256*10^2 g/mol)

= 1.617*10^-2 mol

use:

M = number of mol / volume in L

0.11 = 1.617*10^-2/ volume in L

volume = 0.146978 L

volume = 147 mL

Answer: 147 mL

2)

use dilution formula

M1*V1 = M2*V2

1---> is for stock solution

2---> is for diluted solution

Given:

M1 = 6 M

V1 = 25 mL

V2 = 750 mL

use:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 = (6*25)/750

M2 = 0.200 M

Answer: 0.200 M