17.8k views
24 votes
Calculate the empirical formula of each of the following substances with the following compositions.

a 3.60 g of magnesium and 10.65 g of chlorine


b 9.1 g of lithium and 10.4 g of oxygen

1 Answer

7 votes

Step-by-step explanation:

Note: Molar masses of elements can be found online or in the periodic table.

Moles of Magnesium

= 3.60g / (24.3g/mol) = 0.148mol.

Moles of Chlorine

= 10.65g / (35.45g/mol) = 0.300mol.

Mole ratio of Magnesium to Chlorine

= 0.148mol : 0.300mol = 1 : 2.

Hence we have the empirical formula MgCl2.

Moles of Lithium

= 9.1g / (6.94g/mol) = 1.311mol.

Moles of Oxygen

= 10.4g / (16g/mol) = 0.650mol.

Moles ratio of Lithium to Oxygen

= 1.311mol : 0.650mol = 2 : 1.

Hence we have the empirical formula Li2O.

User Juan Carlos Velez
by
8.6k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.