Question

Using the information in the table, calculate the number of moles in a \pu{7.89 kg}7.89 kg7, point, 89, space, k, g sample of aspirin

Answer 1

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)