What mass of

sucrosse, C12H22O11, is needed to

make 500mL of a 0.20 M solution?

34.23 g

Explanation:

Molarity -

Molarity of a substance, is the number of moles present in a liter of solution.

M = n / V

M = molarity

V = volume of solution in liter,

n = moles of solute,

Moles is denoted by given mass divided by the molecular mass,

Hence,

n = w / m

n = moles,

w = given mass,

m = molecular mass.

From the question,

M = 0.20 M

V = 500mL

Since,

1 L = 1000mL

1 mL = 0.001L

V = 500 mL = 0.5 L

Using the above formula moles can be calculated as -

M = n / V

0.20 M = n / 0.5 L

n = 0.1 mol

The mass of sucrose can be calculated as -

n = w / m

n = 0.1 mol

m (for sucrose) = 342.3 g/mol

0.1 mol = w / 342.3 g/mol

w = 34.23 g