Question

how many moles are present in 4g of sodium hydroxide

Answer 1

Molecular mass = NaOH
= 23+16+1
= 40

Moles = 4/40
=1/10 moles

Answer 2

Given:

Mass of sodium hydroxide (NaOH) = 4 grams

To find:

Number of moles of NaOH in 4 grams

Solution:

The number of moles of sodium hydroxide can be calculated in the following way:

• Step 1: Calculate the molecular mass of sodium hydroxide

• Molecular mass= Sum of the atomic mass of all the atoms
• Molecular mass= Mass of Na + Mass of Oxygen + Mass of Hydrogen
• Molecular mass = 22.989 units + 15.999 units + 1.008 unit
• The molecular mass of NaOH = 39.996 g/mol

• Step 2: Calculate the number of moles by the given formula

• Number of moles = Mass of substance / Molecular mass of a substance
• Number of moles = 4 g / 39.996 g/mol
• Number of moles of NaOH = 0.100 moles

Hence, 0.100 moles are present in 4 grams of NaOH.