An ether contains 60% carbon and 13.3% hydrogen. What is the formula of the ether? |
C2H6O C3H8O C4H10O C5H12O |
C3H8O |
The correct answer is option 2. \(C_3H_8O\). To determine the molecular formula of the ether from the given percentages of carbon and hydrogen, we can follow these steps: Let us assume we have 100 grams of the ether. This simplifies the calculation because the percentages directly translate to grams. Carbon: 60% of 100 grams = 60 grams Hydrogen: 13.3% of 100 grams = 13.3 grams Oxygen: Since the ether contains only carbon, hydrogen, and oxygen, the remaining percentage must be oxygen. So, oxygen percentage = 100% - 60% - 13.3% = 26.7% or 26.7 grams. Molar mass of carbon (C) is 12.01 g/mol \(\text{Moles of C} = \frac{60 \text{ g}}{12.01 \text{ g/mol}} \approx 4.996 \text{ moles}\) Molar mass of hydrogen (H) is 1.008 g/mol \(\text{Moles of H} = \frac{13.3 \text{ g}}{1.008 \text{ g/mol}} \approx 13.198 \text{ moles}\) Molar mass of oxygen (O) is 16.00 g/mol \(\text{Moles of O} = \frac{26.7 \text{ g}}{16.00 \text{ g/mol}} \approx 1.669 \text{ moles}\) Divide the number of moles of each element by the smallest number of moles calculated: \(\text{C: } \frac{4.996}{1.669} \approx 3\) \(\text{H: } \frac{13.198}{1.669} \approx 7.9 \approx 8\) \(\text{O: } \frac{1.669}{1.669} = 1\) The simplest whole number ratio gives us approximately C₃H₈O. |