Question

Sodium hydroxide, NaOH, is a strong base that is used in industrial synthesis and processes such as making paper. What is the mass of 2.60 ×1022 molecules of NaOH (Molar mass = 40.0 g/mol)?

Answer 1

Answer : Mass would be = 1.859 g for NaOH

Explanation : We have got
`2.88 X 10^(22)` molecules of NaOH,

so we get,


`(2.88 X 10^(22) moles of NaOH )/(6.022 X 10^(23)/mol ) X 40.0` g of NaOH/mol

On solving we get, answer as 1.859 g

Hence the g of NaOH will be 1.86.

Answer 2

The mass of 2.60 x10^22 molecules of NaOH is 1.728 grams

calculation
mass = moles x molar mass
molar mass = 40 g/mol

mole is calculated using the Avogadro law
that is 1 mole = 6.02 x10^23 molecules
? = 2.60 x10 ^ 22 molecules

by cross multiplication

(1 mole x 2.60 x10^22) / 6.02 x0^23 = 0.0432 moles

mass is therefore= 0.0432 mole x 40 g/mol = 1.728 grams