Question

4.00g of solid sodium hydroxide is added to water to make a solution with a concentration of
0.200 mol/dm
What is the volume of water used?
A 0.5 cm
B 20 cm
C 500 cm
D 2000 cm​

Answer 1

Answer:

C

Explanation:

concentration of NaOH in mol/dm^3  = concentration of NaOH in g/dm^3/ molar mass of NaOH

Mr of NaOH= 23+ 16+ 1 = 40

M= 40g/ mol

0.2mol=  concentration of NaOH in g/dm^3/ 40g/mol

= 0,2mol/dm^3 x 40g/ mol

= 8g/dm^3

1dm^3= 1000cm^3

4.00g of NaOH will be dissolved in 4g x 1000cm^3/ 8g

=500cm^3 of water

Answer 2

Answer:

C. 500 cm

Explanation:

concentration of NaOH in mol/dm^3  = concentration of NaOH in g/dm^3/ molar mass of NaOH

Mr of NaOH= 23+ 16+ 1 = 40

M= 40g/ mol

0.2mol=  concentration of NaOH in g/dm^3/ 40g/mol

= 0,2mol/dm^3 x 40g/ mol

= 8g/dm^3

1dm^3= 1000cm^3

4.00g of NaOH will be dissolved in 4g x 1000cm^3/ 8g

=500cm^3 of water