Mole Concept

Question

A sample of an oxide of iron contains 7.0 g of iron and 3.0 g of oxygen. If the atomic masses of Fe and O are 56 and 16 respectively, the empirical formula of the oxide is:

RankGuru · Accepted Answer

1. **Convert Masses to Moles**:
   - Moles of Fe = $\frac{7.0}{56} = 0.125$ mol.
   - Moles of O = $\frac{3.0}{16} = 0.1875$ mol.
2. **Find the Simplest Mole Ratio**: Divide each by the smallest value (0.125):
   - Fe: $\frac{0.125}{0.125} = 1$
   - O: $\frac{0.1875}{0.125} = 1.5$
3. **Convert to Whole Numbers**: Multiply both by 2:
   - Fe: $1 	imes 2 = 2$
   - O: $1.5 	imes 2 = 3$
4. **Write the Empirical Formula**: $Fe_2O_3$.
5. **Verification**: In $Fe_2O_3$, the mass ratio is $(2 	imes 56):(3 	imes 16) = 112:48 = 7:3$, which matches the given data exactly.

Mole Concept

Select the correct option:

🔒 Solution Hidden from View

More some basic concepts in chemistry Practice Questions

How many moles of carbon dioxide are produced when 44 g of carbon dioxide is taken at standard condi...

How many moles of oxygen atoms are present in 5.0 g of CaCO3? (Atomic masses: Ca=40, C=12, O=16)

The density of a gas at STP is 1.25 g L⁻¹. Its molar mass is approximately:

The mass percent of nitrogen in NH4 NO3 (Atomic masses: N=14, H=1, O=16) is:

When 9.0 g of aluminium reacts completely with oxygen, how many grams of Al2O3 are formed? (2Al + 3/...

0.50 mol of CaCO3 is heated strongly. How many liters of CO2 (at STP) are evolved? (CaCO3 → CaO + CO...

Which statement correctly defines molality?

If 4.4 g of CO2 contains x molecules, what is x? (Molar mass CO2=44 g mol⁻¹)

A sample of methane contains 0.25 mol. How many hydrogen atoms are present?

A sample contains 3.011×10⁺23 atoms of an element. Its mass is 12 g. The element is:

Determine empirical formula of a compound with 52.17% C, 34.78% O and 13.04% H (Atomic masses: C=12,...

Which statement is correct regarding Avogadro's hypothesis?

About This Question

Solution