Consider the reaction of 82.0 g of oxygen as follows:
4Fe + 3O2 2Fe2O3
How many moles of oxygen react?
How many moles of iron must react?
How many moles of product form?
What mass of product forms?
To answer these questions, we will use the given equation and the molar masses of the elements involved. Here's how to find the answers step by step:
1. How many moles of oxygen react?
To find the number of moles of oxygen, we need to convert the given mass of oxygen (82.0 g) to moles. The molar mass of oxygen (O2) is 32.00 g/mol.
Moles of oxygen = mass of oxygen / molar mass of oxygen
= 82.0 g / 32.00 g/mol
= 2.56 mol
Therefore, 2.56 moles of oxygen react.
2. How many moles of iron must react?
According to the balanced equation, the stoichiometric ratio between iron (Fe) and oxygen (O2) is 4:3. This means that for every 4 moles of iron, 3 moles of oxygen react.
Since we know the number of moles of oxygen (2.56 mol), we can use the stoichiometry to determine the number of moles of iron.
Moles of iron = (moles of oxygen / stoichiometric coefficient of oxygen) * stoichiometric coefficient of iron
= (2.56 mol / 3) * 4
= 3.41 mol
Therefore, 3.41 moles of iron must react.
3. How many moles of product form?
From the balanced equation, we can see that the stoichiometric ratio between oxygen and iron(III) oxide (Fe2O3) is 3:2. This means that for every 3 moles of oxygen that react, 2 moles of Fe2O3 are formed.
Using the number of moles of oxygen we found earlier (2.56 mol), we can calculate the number of moles of Fe2O3 formed.
Moles of Fe2O3 = (moles of oxygen / stoichiometric coefficient of oxygen) * stoichiometric coefficient of Fe2O3
= (2.56 mol / 3) * 2
= 1.71 mol
Therefore, 1.71 moles of Fe2O3 are formed.
4. What mass of product forms?
To find the mass of Fe2O3 formed, we can use the molar mass of Fe2O3, which is 159.69 g/mol.
Mass of Fe2O3 = moles of Fe2O3 * molar mass of Fe2O3
= 1.71 mol * 159.69 g/mol
= 273.25 g
Therefore, 273.25 grams of Fe2O3 are formed.