Question

select the correct answer from each drop - down menu. 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 10.8%, and the percent composition of lead is drop - down menu with options 55.6%, 73.2%, 16.0%, 23.8% reset next

Explanation:

Step1: Calculate total mass of products

The total mass of pure vanadium and pure lead is the sum of their masses. So, \(135 + 915 = 1050\) grams? Wait, no, wait. Wait, the initial mass of vanadinite is 1250 grams. Wait, maybe I misread. Wait, the metallurgist begins with 1250 grams of vanadinite, and ends up with 135 grams of pure vanadium and 915 grams of pure lead. Wait, but 135 + 915 = 1050, which is less than 1250? Maybe there's a mistake, but the problem is about percent composition. Wait, percent composition of an element in a compound is (mass of element / mass of compound) 100. But here, maybe it's the percent composition in the ore (the vanadinite) or in the products? Wait, the question is "What are the percent compositions of vanadium and lead?" Given that the initial mass is 1250 g of vanadinite, and the final masses are 135 g V and 915 g Pb. Wait, maybe the percent composition is (mass of element / initial mass of ore) 100. Let's check vanadium first: (135 / 1250) 100 = 10.8%, which matches the given value. Now for lead: (915 / 1250) 100. Let's calculate that. 915 divided by 1250. 1250 0.732 = 915, because 1250 0.7 = 875, 1250 0.032 = 40, so 875 + 40 = 915. So (915 / 1250) 100 = 73.2%. So the percent composition of lead is 73.2%.

Step2: Verify the calculation for lead

We have the mass of lead as 915 grams and the mass of the ore (vanadinite) as 1250 grams. The formula for percent composition is \(\frac{\text{mass of element}}{\text{mass of compound (ore)}} \times 100\). Plugging in the values: \(\frac{915}{1250} \times 100\). Simplify \(\frac{915}{1250}\) first. Divide numerator and denominator by 5: 183/250. Then multiply by 100: (183/250)100 = (183100)/250 = 18300/250 = 73.2. So the percent composition of lead is 73.2%.

Answer:

73.2%