Question

2. A normal dose of ibuprofen is 200. mg. How many ibuprofen molecules are there in a dose of ibuprofen? The molecular formula of ibuprofen is C13H18O2. (Hint: grams to mol and mol to molecules)

3-Propane fuel is used in BBQs. Use the following reaction to determine how many moles of carbon dioxide gas are produced from burning of 6 moles of propane gas.

C3H8(g) + 5O2(g) ®  4H2O(g) + 3CO2(g)

4- A. If a person inhales 51 moles of oxygen, how many grams of oxygen molecules are being inhaled?

B. How many molecules are being inhaled?

Answer 1

2.
The molecular formula of ibuprofen is C13H18O2
The atomic masses of C, H and O are 12 g/mol, 1 g/mol and 16 g/mol respectively.
The molar mass of ibuprofen is
200 mg = 0.200 g
Number of moles $= \dfrac {0.200 \: g}{206 \: g/mol} = 0.0009709 \: mol$
Number of molecules $= 0.0009709 \: mol \times 6.023 \times 10^{23} = 5.85 \times 10^{20} \;$ molecules

3.
The burning of 1 mole propane produces 3 moles of CO2.
The burning of 6 mole propane produces $3 \times 6 = 18$ moles of CO2

4.A
The molar mass of oxygen is 32 g/mol.
Grams of oxygen molecules inhaled $= 51 \: mol \times 32 \: g/mol = 1632 \: g$
B
Number of molecules being inhaled $= 51 \: moles \times 6.023 \times 10^{23} \: molecules/mol = 3.07 \times 10^{25} \: molecules$