To calculate the number of moles in 0.025 g of (NH₄)₂Cr₂O₇ (ammonium dichromate), you need to follow these steps:
Calculate the molar mass of (NH₄)₂Cr₂O₇:
N (Nitrogen): 14.01 g/mol x 2 = 28.02 g/mol
H (Hydrogen): 1.01 g/mol x 8 = 8.08 g/mol
Cr (Chromium): 52.00 g/mol x 2 = 104.00 g/mol
O (Oxygen): 16.00 g/mol x 7 = 112.00 g/mol
Molar mass of (NH₄)₂Cr₂O₇ = 28.02 + 8.08 + 104.00 + 112.00 = 252.00 g/mol (approximately)
Use the formula:
Moles = Mass / Molar mass
Plug in the values:
Moles = 0.025 g / 252.00 g/mol
Calculate:
Moles ≈ 0.0000992 moles or 9.92 x 10⁻⁵ moles
Therefore, there are approximately 9.92 x 10⁻⁵ moles of (NH₄)₂Cr₂O₇ in 0.025 g.
