Question

What mass of
sucrosse,C12H22O11, is needed to
make 500mL of a 0.20 M solution?

Answer 1

34.23 g

Step-by-step 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