Question

Determination of Number of Atoms by Mass
Q1: Calculate no. of atoms in 46g of Na.
Q4:
Q2: Calculate no of atoms in 98g of Ca.
Q5:
Q3: Calculate no. of atoms in 500g of Zn.
Q6:
Q7: Calculate the number of atoms in 9g of Al.
Q8: Calculate the mass of one atom of carbon in grams.

Can anyone solve the problem ​

Answer 1

Answer:

1. molar mass of Na 23

no of moles = 46/23 = 2

no of atoms = 2×6.023×10²³ = 12.046×10²³

2. molar mass of Ca = 40

no of moles = 98/40 = 2.45

no of atoms = 2.45× 6.023×10²³ = 14.75×10²³

3. molar mass of Zn = 65.38

no of moles = 500/65.38 = 7.64

no of atoms = 7.64×6.023×10²³ = 46.01×10²³

4. molar mass of Al =26.998

no of moles = 9/26.998 = 0.333

no of atoms = 0.333×6.023×10²³ = 2.005×10²³

5. molar mass 12 divided by 6.023×10²³ = 1.994×10²³g