Question

There are 1.20g of Cobalt and 1.80g of oxygen. What is the molar ratio?

Answer 1

Explanation:

The steps for determining the empirical formula of a compound are as follows:

Step 1: Obtain the mass of each element present in grams

Element % = mass ( in g)

Step 2: Determine the number of moles of each type of atom present

mass / atomic mass = Mole (M)

Step 3: Divide the number of moles of each element by the smallest number of moles

Mole / least moles value = Atomic Ratio (R)

Step 4: Convert numbers to whole numbers. This set of whole numbers are the subscripts in the empirical formula.

R * whole number = Empirical Formula

Calculations:

Step 1: Obtain the mass of each element present in grams

Mass of Co = 1.20 g

Mass of Oxygen = 1.80 g

Step 2: Determine the number of moles

mass / atomic mass = Mole (M)

moles of Co = 1.20 g / 58.93 g/mol = 0.02036

moles of O = 1.80 g / 16 g/mol = 0.1125

Step 3: Divide the number of moles of each element by the smallest number of moles

Here list mole is 0.02036

Atomic ratio for Co = 0.02036 / 0.02036 = 1

Atomic ratio for O = 0.1125 / 0.02036 = 5.52

Step 4: Convert into whole number

We got ratio of Co : O = 1:5.52

multiply it by 2 to get whole number of Co : O = 2  × [1:5.52] = 2:11

Hence the molar ratio of Co : O = 2 : 11