Question

If 5.85g of table salt, NaCI, are dissolved in water to make a solution of 250ml, what is the concentration of the solution, in mol/dm3 or mol/l?

Answer 1

Step-by-step explanation: 0.4004mol/L

Given

Mass of NaCl = 5.85g

no of moles of NaCL =Mass/ molar mass

but molar mass of NaCl= (22.99 g/mol + 35.45 gmol )= 58.44 g/mol.

therefore, Number of moles= 5.85g/ 58.44g/mol= =0.100 moles

Also, converting 250ml to litres becomes 250/1000= 0.25L

Concentration of the solution in mol /L =

Concentration = number of moles of solutes/ total volume of solution

therefore C= n/v= 0.100moles/ 0.25L = 0.4004mol/L

Answer 2

CONCENTRATION IS 0.4 mol/dm3

Step-by-step explanation:

If 5.85g of table salt, NaCI, are dissolved in water to make a solution of 250ml, what is the concentration of the solution, in mol/dm3 or mol/l?

Mass = 5.85 g

Substance = NaCl

Volume = 250 mL = 0.25 L

Concentration in mol/dm3 = concentration in g/dm3 / Relative Molecular mass

Step 1: calculate the concentration in g/dm3

5.85 g = 0.25 L

(5.85 / 0.25) g = 1 L

Concentration in g/dm3 = 23.4 g/dm3

Step 2: calculate the relative molecular mass of NaCl

(Na= 23, Cl = 35.5)

RMM = (23+ 35.5)

RMM = 58.5 g/mol

Step 3: calculate the concentration in mol/dm3

Conc. in mol/dm3 = Conc. in g/dm3 / RMM

Conc. in mol/dm3 = 23.4 g/dm3 / 58.5 g/mol

Conc. in mol/dm3 = 0.4 mol/dm3

So therefore, the concentration in mol/dm3 of the solution is 0.4 mol/dm3