How many grams are contained in 10.00 mol of lithium sulfate, Li2SO4?
The correct answer and explanation is:
To find how many grams are contained in 10.00 moles of lithium sulfate (Li₂SO₄), you need to follow these steps:
Step 1: Determine the molar mass of lithium sulfate (Li₂SO₄).
- Lithium (Li) atomic mass = 6.94 g/mol
- Sulfur (S) atomic mass = 32.07 g/mol
- Oxygen (O) atomic mass = 16.00 g/mol
Lithium sulfate has:
- 2 lithium atoms
- 1 sulfur atom
- 4 oxygen atoms
Calculate the molar mass:
Molar mass of Li₂SO₄ = (2 × 6.94) + (1 × 32.07) + (4 × 16.00)
= 13.88 + 32.07 + 64.00
= 109.95 g/mol
Step 2: Use the molar mass to convert moles to grams.
The formula to convert moles to grams is:
mass (g)=number of moles×molar mass (g/mol)\text{mass (g)} = \text{number of moles} \times \text{molar mass (g/mol)}
Given:
Number of moles = 10.00 mol
Molar mass = 109.95 g/mol
Calculate the mass:
mass=10.00×109.95=1099.5 grams\text{mass} = 10.00 \times 109.95 = 1099.5 \text{ grams}
Final answer:
10.00 moles of lithium sulfate contain 1099.5 grams.
Explanation:
Moles measure the amount of substance based on the number of particles (atoms, ions, or molecules). Each compound has a characteristic molar mass—the mass of one mole of that compound. This molar mass depends on the sum of the atomic masses of all atoms in the formula.
For lithium sulfate (Li₂SO₄), the molar mass is calculated by adding the atomic masses of lithium, sulfur, and oxygen in their respective quantities. Lithium is light with a mass of 6.94 g/mol, sulfur is heavier at 32.07 g/mol, and oxygen atoms weigh 16.00 g/mol each. By multiplying these atomic masses by their subscripts in the chemical formula and adding them, you get the total molar mass.
Once the molar mass is known, converting moles to grams is straightforward: multiply the number of moles by the molar mass. Since the user has 10 moles of Li₂SO₄, the mass will be 10 times the molar mass, yielding approximately 1100 grams.
This conversion is critical in chemistry for preparing solutions, reactions, and understanding stoichiometry — the quantitative relationships between reactants and products in chemical reactions.