Problem: Lead is found in Earths crust as several different lead ores. Suppose a certain rock is composed of 38.0% PbS (galena), 25.0% PbCO3 (cerussite), and 17.4% PbSO4 (anglesite). The remainder of the rock is composed of substances containing no lead.How much of this rock (in kg) must be processed to obtain 5.1 metric tons of lead? (A metric ton is 1000 kg.)

FREE Expert Solution

We are asked how much of this rock (in kg) must be processed to obtain 5.1 metric tons of lead.


Calculate mass percent of lead in each: 


PbS:

% Pb = MMPbMM PbS×100% Pb = 207.2239.27×100

% Pb = 86.60 %


PbCO3

% Pb = MMPbMM PbCO3×100% Pb = 207.2267.21×100

% Pb = 77.54 %


PbSO4

% Pb = MMPbMM PbSO4×100% Pb = 207.2303.27×100

% Pb = 68.32 %


Calculate mass % for the rock: 

% Pb = (0.38)(86.60)+(0.25)(77.54)+(0.174)(68.32)

% Pb = 64.18 %


View Complete Written Solution
Problem Details

Lead is found in Earths crust as several different lead ores. Suppose a certain rock is composed of 38.0% PbS (galena), 25.0% PbCO3 (cerussite), and 17.4% PbSO4 (anglesite). The remainder of the rock is composed of substances containing no lead.

How much of this rock (in kg) must be processed to obtain 5.1 metric tons of lead? (A metric ton is 1000 kg.)

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Mass Percent Formula concept. You can view video lessons to learn Mass Percent Formula. Or if you need more Mass Percent Formula practice, you can also practice Mass Percent Formula practice problems.