Question

If density of methanol is 0.793 kg / L , what is its volume needed for making 2.5 L of its 0.25 M solution ?

Answer 1

Dear Student,

Solution of the question asked by you is as follow:

Given here,

Density of methanol = 0.793 kg/L

Volume of solution = 2.5 L

Molarity of solution = 0.25 M

As we know that,

Molarity = Number of moles of solute/ volume of solution in L ............... (i)

0.25 = Number of moles of methanol / 2.5 L

Number of moles of methanol = Mass of methanol / Molar mass of methanol

Molar Mass of Methanol (CH₃OH) = 12 + (4 × 1) + 16 = 32 g

Putting all the values in relation (i), we get:

Mass of Methanol = 0.625 × 32 g

= 2.000 g = 2g

= 0.002 kg

As we know that

Density = Mass/volume

0.793 = 0.002 / volume

Volume = 0.002/0.793

Volume = 0.0025 L

Hope it answers your query!