How many moles are in a 12 g sample of FeO?
The correct answer and explanation is:
To find the number of moles in a 12 g sample of FeO, the first step is to calculate the molar mass of FeO.
Step 1: Calculate molar mass of FeO
- Iron (Fe) atomic mass ≈ 55.85 g/mol
- Oxygen (O) atomic mass ≈ 16.00 g/mol
- Molar mass of FeO = 55.85 + 16.00 = 71.85 g/mol
Step 2: Use the formula to find moles
Number of moles = mass of sample / molar mass
= 12 g / 71.85 g/mol
≈ 0.167 moles
So, a 12 gram sample of FeO contains approximately 0.167 moles.
Explanation:
A mole is a fundamental unit in chemistry that represents 6.022 × 10²³ particles (atoms, molecules, or ions). The molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). By knowing the molar mass of FeO, you can convert between the mass of a sample and the number of moles it contains.
In this example, FeO is a compound made of one iron atom and one oxygen atom. Adding their atomic masses gives the molar mass of FeO. Dividing the mass of the sample by the molar mass yields the number of moles. This calculation is important because it allows chemists to relate the mass of a substance to the number of particles or entities involved in a chemical reaction, enabling stoichiometric calculations and predictions.
This method can be applied to any compound by determining its molar mass and then dividing the given mass by that molar mass to find the amount in moles.