3.618X 10^24 molecules of sodium hydroxide (NaOH) would also be grams of NaOH

Mass = 240 g

Explanation:

Given data:

Number of molecules of NaOH = 3.618 × 10²⁴ molecules

Mass in grams = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For NaOH:

1 mole = 6.022 × 10²³ molecules

3.618 × 10²⁴ molecules × 1 mol /  6.022 × 10²³ molecules

0.6 × 10¹ moles

6 moles

Mass of NaOH:

Mass = Number of moles × molar mass

Mass = 6 mol × 40 g/mol

Mass = 240 g

(A) because the pressure, volume and the number of moles are known so (B), (C), (D) are not the right answer so (A) must be the answer.