Question

4) Calculate the mass of

(b) 0.07 mole of HCI ​

Answer 1

2.555 g is the required answer.

GIVEN:

Number of moles, n = 0.007

TO FIND:

Mass of 0.07 moles of HCl , m

FORMULA:

Number of moles, n = mass / molecular mass

n = m/ M

Here M is the molecular mass of HCl

SOLUTION:

STEP1:

TO FIND MOLECULAR MASS OF HCl:

We know that,

• Atomic mass of hydrogen , H = 1 g

• Atomic mass of chlorine, Cl = 35.5 g

Molecular mass of HCl = Atomic mass of H + Atomic mass of Cl

Molecular mass, M = 1 + 35.5

M = 36.5 g

Molecular mass of HCl is 36.5 g

STEP 2:

TO FIND REQUIRED MASS :

n = m/ M

0.07 = m / 36.5

m = 0.07 × 36.5

m = 2.555 g

ANSWER:

Mass of 0.07 moles of HCl is 2.555 g