Question

How many molecules are in 25g of Na2SO4?

Answer 1

Hey there!

Molar mass Na2SO4 = 142.04 g/mol

Number of moles:

n = m / mm

n = 25 / 142.04

n = 0.176 moles of Na2SO4

Therefore, use the Avogadro constant

1 mole Na2SO4 ------------------- 6.02x10²³ molecules
0.176 moles Na2SO4 ------------ molecules ??


0.176 x ( 6.02x10²³ ) / 1

=> 1.059x10²³ molecules of Na2SO4

hope this helps!

Answer 2

The correct answer is: 1,059x10²³ molecules of Na2SO4

Step-by-step explanation:

Hello! Let's solve this!

The data we have are:

Molar mass Na2SO4 = 142.04 g / mol

Na2SO4 mass = 25 g

Number of moles:

n = 25g / 142.04g / mol = 0.176mol

Each one mole of substance there are 6.02x10²³ molecules

Then we calculate the number of molecules:

molecules = 0.176mol * 6.02x10²³ molecules / mol = 1.059x10²³ molecules of Na2SO4

The correct answer is: 1,059x10²³ molecules of Na2SO4