Galena, a mineral of lead, is a compound of the metal with sulfur. Analysis shows that a 234-9 sample of galena contains 203 g of lead. Calculate the (a) mass of sulfur in the sample; (b) mass fractions of lead and sulfur in galena; (c) mass percents of lead and sulfur in galena

a) 31 g

b) 0.867, 0.132

c) 86.75%, 13.24%

Explanation:

Given:

Mass of the sample of galena = 234 g

Mass of the lead in the sample = 203 g

Now,

galena = sulfur + lead

thus,

a) Mass of the sulfur will be calculated as:

= mass of the sample of galena - mass of lead

on substituting the values, we have

= 234 - 203

or

= 31 g

b) Now,

the mass fraction of lead will be calculated as = (mass of lead) / (total mass of the galena sample)

= 203/234 = 0.867

and,

Mass fraction of sulfur will be = (mass of the sulfur in the sample) / (total mass of the sample)

thus we have

= 31/234

⇒ 0.132

(c) Now the mass percentage of lead in the sample = (mass of lead in the sample) / (total mass of sample) * 100%

= (203 / 234) x 100%

= 86.75%

and

the mass percentage of sulfur in the sample = (mass of sulfur in the sample) / (total mass of the sample) * 100%

= (31 / 234) * 100%

⇒ 13.24%