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Phosphorus combines with hydrogen to form phosphine. If 108.3 g of phosphorus reacts with hydrogen to produce 129.9 g of phosphine, what is the percent by mass of each element in phosphine?

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To find the percent by mass of each element in phosphine (PH3), you can follow these steps:

Determine the molar masses of the elements involved:

Phosphorus (P) has a molar mass of approximately 30.97 g/mol.

Hydrogen (H) has a molar mass of approximately 1.01 g/mol.

Calculate the molar mass of phosphine (PH3):

PH3 consists of one phosphorus atom and three hydrogen atoms.

Molar mass of PH3 = (1 * molar mass of P) + (3 * molar mass of H)

Molar mass of PH3 = (1 * 30.97 g/mol) + (3 * 1.01 g/mol) = 34.00 g/mol

Determine the mass of each element in 129.9 g of phosphine:

Mass of phosphorus (P) in 129.9 g of PH3 = (1 * 30.97 g/mol) = 30.97 g

Mass of hydrogen (H) in 129.9 g of PH3 = (3 * 1.01 g/mol) = 3.03 g

Calculate the percent by mass of each element:

Percent by mass of phosphorus (P) = (Mass of P / Total mass of PH3) * 100%

Percent by mass of P = (30.97 g / 129.9 g) * 100% ≈ 23.85%

Percent by mass of hydrogen (H) = (Mass of H / Total mass of PH3) * 100%

Percent by mass of H = (3.03 g / 129.9 g) * 100% ≈ 2.33%

So, the percent by mass of phosphorus in phosphine (PH3) is approximately 23.85%, and the percent by mass of hydrogen is approximately 2.33%.

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