Question

Calculate the percent mercury and nitrogen in mercuric cyanide, hg(cn)₂

a. 20.0% Hg, 40.0% N
b. 79.4% Hg, 6.2% N
c. 79.4% Hg, 11.1% N
d. 83.4% Hg, 11.6% N
e. 88.5% Hg, 6.2% N.

Answer 1

The percent composition of mercury in mercuric cyanide is 79.4%, and the percent composition of nitrogen is 11.1%. The correct answer is option c.

Step-by-step explanation:

To calculate the percent composition of mercury (Hg) and nitrogen (N) in mercuric cyanide (Hg(CN)2), we need to know the molar masses of mercury, carbon (C), and nitrogen. The molar mass of mercury is 200.59 g/mol, of carbon is 12.01 g/mol, and of nitrogen is 14.01 g/mol.

Mercuric cyanide consists of one mercury atom, two carbon atoms, and two nitrogen atoms. The molar mass of mercuric cyanide is thus: Molar mass = (1 × 200.59) + (2 × 12.01) + (2 × 14.01) = 200.59 + 24.02 + 28.02 = 252.63 g/mol. Percent mercury = (mass of Hg / molar mass of Hg(CN)2) × 100%.

Percent mercury = (200.59 / 252.63) × 100% = 79.4%. Percent nitrogen = (mass of N × 2 / molar mass of Hg(CN)2) × 100%. Percent nitrogen = (14.01 × 2 / 252.63) × 100% = 11.1%. Hence, the correct answer is c. 79.4% Hg, 11.1% N.