Question

You purchased a 5.00 pound bag of sugar (sucrose, C12H22O11) at the grocery last week to bake cookies. Conversion: 1 pound = 1 lb = 454 grams.

a.How many grams of sucrose did you purchase?
454 grams (g) = 1 pound (lb)
454 g * 5 = 2270 g

A 5 pound bag of sugar is equal to 2270 grams of sugar.

b.Calculate the formula weight of sucrose.
Formula weight = mass of Carbon + mass of Hydrogen + mass of Oxygen
= (12.0107 * 12) + (1.00794 * 22) + (15.9994 * 11)
=144.1284 + 22.17468 + 175.9934
=342.29648
=342.396 g/mol

c.How many moles of sucrose did you purchase?
2270g C12H22O11 * (1 mol)/(342.396 g/mol) =6.62975034755 moles

2270 grams of C12H22O11 is equal to 6.632 moles

d.In a separate shopping trip you bought a container of sucrose that contained 1.76 x 1024 sucrose molecules. How many grams of sucrose did you purchase?

I was able to complete parts a-c but i'm not sure how to solve part d.

Answer 1

mols sucrose in 1.76E24 molecules = molecules/6.02E23 = ?
Then grams = mols x molar mass = ?

I didn't check the math on a through c but the method is right.