Determine the mass percent H in NH₄Cl.

Question

Quizplus · Accepted Answer

To determine the mass percent H, we need to divide the mass of H in the compound by the total mass of the compound and then multiply by 100%. The compound contains 1 H atom, which has a molar mass of 1 g/mol.

To find the total mass of the compound, we need to add up the masses of all the atoms:
N (14 g/mol) x 1 = 14 g/mol
H (1 g/mol) x 1 = 1 g/mol
S (32 g/mol) x 1 = 32 g/mol
Cl (35.5 g/mol) x 1 = 35.5 g/mol
U (238 g/mol) x 2 = 476 g/mol
B (10.8 g/mol) x 2 = 21.6 g/mol

Total mass of compound = 580.1 g/mol

Now we can calculate the mass percent H:
(1 g/mol H / 580.1 g/mol compound) x 100% = 0.172% 
Rounding to one significant figure gives a mass percent of 0.2%, which is closest to answer choice C, 7.5%.

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Determine the Mass Percent H in NH₄Cl