A chemist wants to extract the gold from 15.0g of gold(II) chloride dihydrate, AuCl3 • 2H20, What mass of gold could be obtained from this sample?
I can't read the formula but I will assume it is AuCl3.2H2O.
15.0 g x (atomic mass Au/molar mass AuCl3.2H2O) = grams Au
To calculate the mass of gold that can be obtained from the given sample of gold(II) chloride dihydrate, we'll need to consider the molar masses and stoichiometry of the compounds involved.
Step 1: Find the molar mass of gold(II) chloride dihydrate (AuCl3 • 2H2O):
- Molar mass of Au = 197.0 g/mol
- Molar mass of Cl = 35.5 g/mol
- Molar mass of H2O = 18.0 g/mol
- Molar mass of AuCl3 • 2H2O = (197.0 g/mol) + (3 * 35.5 g/mol) + (2 * 18.0 g/mol)
- Molar mass of AuCl3 • 2H2O = 303.5 g/mol
Step 2: Calculate the number of moles of gold(II) chloride dihydrate:
- Moles = Mass / Molar mass
- Moles = 15.0 g / 303.5 g/mol
Step 3: Determine the stoichiometry of the reaction:
- The balanced chemical equation for the reaction is:
AuCl3 • 2H2O → Au + 3Cl + 2H2O
- According to the equation, one mole of AuCl3 • 2H2O yields one mole of Au.
Step 4: Calculate the moles of gold that can be obtained:
- Moles of Au = Moles of AuCl3 • 2H2O
Step 5: Convert the moles of gold to grams:
- Mass of Au = Moles of Au * Molar mass of Au
Now, let's calculate the mass of gold that could be obtained from the given sample:
Molar mass of AuCl3 • 2H2O = 303.5 g/mol
Moles of AuCl3 • 2H2O = 15.0 g / 303.5 g/mol
Moles of Au = Moles of AuCl3 • 2H2O
Mass of Au = Moles of Au * Molar mass of Au
Therefore, the mass of gold that could be obtained from the sample is equal to the product of the moles of gold and the molar mass of gold.
To determine the mass of gold that could be obtained from the given sample, we need to use the molar mass and stoichiometry of the chemical equation.
1. Calculate the molar mass of AuCl3 • 2H2O:
- Molar mass of Au: 196.97 g/mol
- Molar mass of Cl: 35.45 g/mol
- Molar mass of H: 1.01 g/mol
- Molar mass of O: 16.00 g/mol
Since there are three chloride ions (Cl-) and two water molecules (2H2O) in the formula, multiply their molar masses accordingly.
Molar mass of AuCl3 • 2H2O = (196.97 g/mol) + 3(35.45 g/mol) + 2[(2(1.01 g/mol) + 16.00 g/mol)]
= 196.97 g/mol + 106.35 g/mol + 36.04 g/mol
= 339.36 g/mol
2. Convert the given mass of AuCl3 • 2H2O (15.0 g) to moles:
- Moles = mass / molar mass
Moles of AuCl3 • 2H2O = 15.0 g / 339.36 g/mol
≈ 0.044 mol
3. Use the stoichiometry of the balanced chemical equation to find the moles of gold (Au):
- The balanced chemical equation is:
AuCl3 • 2H2O → Au + 2H2O + 3Cl-
From the equation, we can see that one mole of AuCl3 • 2H2O produces one mole of Au.
Therefore, the moles of Au in the sample are also 0.044 mol.
4. Convert the moles of Au to mass using the molar mass of Au:
- Mass = moles × molar mass
Mass of Au = 0.044 mol × 196.97 g/mol
= 8.67 g
Therefore, approximately 8.67 grams of gold could be obtained from the given sample.