Question

Determine the molarity of each of the following solutions:

(d) 2.76 kg of CuSO4?5H2O in 1.45 L of solution

(e) 0.005653 mol of Br2 in 10.00 mL of solution

(f) 0.000889 g of glycine, C2H5NO2, in 1.05 mL of solution

Please show me above answers step by step

thanks...

Answer 1

d)

Molar mass of CuSO4.5H2O,

MM = 1*MM(Cu) + 1*MM(S) + 9*MM(O) + 10*MM(H)

= 1*63.55 + 1*32.07 + 9*16.0 + 10*1.008

= 249.7 g/mol

mass(CuSO4.5H2O)= 2.76 Kg

= 2760.0 g

use:

number of mol of CuSO4.5H2O,

n = mass of CuSO4.5H2O/molar mass of CuSO4.5H2O

=(2760.0 g)/(2.497*10^2 g/mol)

= 11.05 mol

volume , V = 1.45 L

use:

Molarity,

M = number of mol / volume in L

= 11.05/1.45

= 7.623 M

Answer: 7.62 M

e)

volume , V = 10.00 mL

= 1*10^-2 L

use:

Molarity,

M = number of mol / volume in L

= (5.653*10^-3)/(1*10^-2)

= 0.5653 M

Answer: 0.565 M

f)

Molar mass of C2H5NO2,

MM = 2*MM(C) + 5*MM(H) + 1*MM(N) + 2*MM(O)

= 2*12.01 + 5*1.008 + 1*14.01 + 2*16.0

= 75.07 g/mol

mass(C2H5NO2)= 0.000889 g

use:

number of mol of C2H5NO2,

n = mass of C2H5NO2/molar mass of C2H5NO2

=(8.89E-4 g)/(75.07 g/mol)

= 1.184*10^-5 mol

volume , V = 1.05 mL

= 1.05*10^-3 L

use:

Molarity,

M = number of mol / volume in L

= 1.184*10^-5/1.05*10^-3

= 1.128*10^-2 M

Answer: 1.128*10^-2 M