posted by hilde on .
in an experiment a sample of hydrocarbon was analyzed. The sample contained6 g of carbon and 1.344 g Hydrogen.
a) whats the empirical formula?
the density of hydrocarbon at 25 C and 1.09 atm is 1.96 g/L
b.) whats the molar mass of the hydrocarbon?
c) whats the molecular formula?
1. Calculate percent C and percent H.
2. Take a 100 g sample, and convert percent to grams C and H.
3. Convert grams to moles C and moles H. moles = grams/atomic mass.
4. Find the ratio of C and H to each other in small whole numbers. The easy way to do that is to divide the smaller value by itself; then divide the other number by the same small number. Round to whole numbers but don't round if the value is more than 0.1 away from a whole number. In that case, multiply each number by a factor (2x, 3x, 4x, 5x etc) until you obtain two whole numbers within rounding of 0.1.
b. After the formula is obtained, just add the atomic masses.
c. Use PV = nRT. For density that is
P*molar mass = density*R*T.
Post your work if you stuck.