Question.

A solid weigh 16.5N on the surface of the moon. The force of gravity on the moon is 1.7N/Kg. Determine the mass of the solid.

Answer.

Note weight= Mass x gravity. Since we are given weight and gravity, we can easily find mass.

Therefore Mass=weight/gravity= 16.5/1.7= 9.71Kg.

1. 0.23 g of Sodium atoms.
2. 0.23 g of Chlorine atoms.
3. 0.23 g of Chlorine molecules.
4. 0.23 g of dilute sulphuric (VI)acid.

Question.

Calculate the number of moles present in:

1. 0.23 g of Sodium atoms.
2. 0.23 g of Chlorine atoms.
3. 0.23 g of Chlorine molecules.
4. 0.23 g of dilute sulphuric (VI)acid.

Answers.

a) 0.23 g of Sodium atoms
Molar mass of Sodium atoms = 23g
Moles = (Mass in grams/Molar mass) = > 0.23g/23g = 0.01moles

b) Molar mass of Chlorine atoms = 35.5 g
Moles = mass in grams/molar mass = > 0.23g/35.5g = 0.0065moles /6.5 x 10-3 moles

c) Molar mass of Chlorine molecules = (35.5 x 2) = 71.0 g
Moles = mass in grams/molar mass = > 0.23g/71.0g = 0.0032moles /3.2 x 10-3 moles
d) Molar mass of H2SO4 = [(2 x 1) + 32 + (4 x14)] = 98.0g
Moles = mass in grams/molar mass = > 0.23g/98g = 0.0023moles /2.3 x 10-3 moles