Question

What are the percent compositions of vanadium and lead?
A metallurgist begins with 1,250 grams of vanadinite (Pb5(VO4)3Cl) and ends up with 135 grams of pure vanadium and 915 grams of pure lead. The percent composition of vanadium in the ore is 1._____ , and the percent composition of lead is 2.____ .

OPTIONS:

1.
A. 10.8%
B. 14.3%
C. 14.8%
D. 62.4%

2.
A. 55.6%
B. 73.2%
C. 16.0%
D. 23.8%

Answer 1

Answer:

1. 10.8%

2. 73.2%

Explanation:

1) Data

i) Sample: 1,250 grams of vanadinite (Pb₅ (VO₄)₃Cl

ii) V = 135 g

iii) Pb = 915 g

iv) % V = ?

v) % Pb =?

2) Formula

% composition =( mass in grams of element / mass in grams of sample) × 100

3) Solution

i) Vanadium

% V = (mass of V / mass of sample) × 100 = (135 g/ 1,250 g) × 100

% V = 10.8 % ← answer

ii) Lead

% Pb = (mass of Pb / mass of sample) × 100 = (915 g / 1,250 g) × 100

% Pb = 73.2% ← answer