Question

1. Calculate the number of moles of carbon atoms present in 2.4g of ethanol (C2H6O).

2. What is the % Nitrogen by weight in 3.696 mol of ammonium sulfide.

3. How many atoms of mercury are present in 5.4 cubic cm of liquid mercury? The density of mercury is 13.55g/cc.

Answer 1

1. moles = grams/molar mass
2. (mass nitrogen/mass amm sulfide)*100 = ??
3. mass Hg = volume x density
Then convert to moles.
Then remember there are 6.022E23 atoms for every mole.

Answer 2

3.50 mol x 6.022 x 10^23
= 2.11 x 10^24 carbon atoms