We have to find the number of moles in a 7.89 kg sample of aspirin.
The formula of aspirin is: C₉H₈O₄
We are given the molar mass of C, H and O:
H: 1.008 g/mol C: 12.01 g/mol O: 16.00 g/mol
Since one molecule of aspirin has 9 atoms of C, 8 atoms of H and 4 atoms of O, and using the molar masses given, we can calculate the molar mass of aspirin:
molar mass of aspirin = 9 * 12.01 g/mol + 8 * 1.008 g/mol + 4 * 16.00 g/mol
molar mass of aspirin = 180.154 g/mol
Before we find the number of moles we can convert 7.89 kg to g. Since we know that there are 1000 g in 1 kg, we can convert it like this:
1000 g = 1 kg
mass of sample = 7.89 kg * 1000 g/1 kg
mass of sample = 7890 g
Finally, we can find the number of moles in the sample using the molar mass.
number of moles = 7890 g * 1 mol/180.154 g
number of moles = 43.795 moles
Answer: The number of moles in the sample is 43.8 moles (using 3 SF)
