Chemistry homework please help! It's due Monday!!!!!!!!!?

Question

Help me solve this problem!
The molecular formula of a hydrocarbon is to be determined by analyzing its combustion products and investigating its colligative properties.
1) The hydrocarbon burns completely, producing 7.2 grams of water and 7.2 liters of CO2 at standard conditions. Calculate the empiracle formula of teh hydrocarbon.
2) Calculate the mass in grams of O2 required for the complete combustion of the sample of the hydrocarbon described in part 1.
3) The hydrocarbon dissolves readily in CHCl3. The freezing point of a solution prepared by mixing 100 grams of CHCl3 and .600 gram of the hydrocarbon is -64.0 degrees celcius. The molar freezing point depression constant of CHCl3 is 4.68 degrees celcius per molal and its normal freezing point is -63.5 degrees celcius. Calculate the molecular weight of the hydrocarbon.
4) What is the molecular formula of the hydrocarbon?

Answer 1

This interesting question will take some work.

Here are the steps you need to do.

First, you need a balanced equation. All hydrocarbons react with O2 to produce water and CO2. You are given the grams of water and the volume of CO2 at STP. Convert these to moles. Based on this you can work the stoichiometry to calculate the moles of Oxygen. This will also give you the grams of oxygen. You shouuld be able to use the balanced equation to calculate the mix of carbon and hydrogen in the hydrocarbon and get the empirical formula.

The formula for the freezing pt. depression is

Delta T = Kf m (where m is the molality or moles of solute per kg. of solvent)

You are given the kg. of solvent and the Kf. The delta T is clearly 0.5 C. You can solve for the moles of the unknown. Since you are given the grams used, you can now calulculate the molecular mass and determine the actual molecular formula.

Good luck!

Answer 2

Problems in Stoichiometry: Empirical formulas, reactions

A certain organic compound is found by analysis to contain 31.9% carbon and 5.30% hydrogen, by weight. A qualitative test shows chlorine to be present as well. On the assumption that the only elements present are carbon, hydrogen, and chlorine, find the simplest formula of the compound.


Two hydrocarbons, one a gas and the other a solid, have the same composition. When either hydrocarbon is burned, the weight of carbon dioxide produced is 3.26 times the weight of water formed.

A hydrocarbon is found to contain 93.46% carbon and 6.54% hydrogen.

The molecular formula for a hydrocarbon is to be determined by analyzing its combustion products. The hydrocarbon burns completely, producing 7.2 grams of water and 7.2 liters of CO2 gas at standard condition (1 mole of a gas occupies 22.4 liters at STP).

Carbon - 49.02% Hydrogen - 2.743% Chlorine 48.23%

Propane, C3H8, is a hydrocarbon that is commonly used as fuel for cooking.

Answer 3

1) 22.4 l of CO2 comes from 1 mol of C
7.2 l of CO2 comes from 1/3 mol C (approx)

Similarly 7.2 g H2O needs 7.2/18 mol = 2/5 mol

Empirical formula is C5H6

2) Mass of O2 is

Answer 4

at the same time as someone takes a Tum for acid indigestion. The hydrochloric acid on your abdomen is neutralized at the same time as it is going into your small gut at the same time as baking soda is used as a leavening agent( to make the cake upward thrust) it must have an acid portion of launch the CO2 gas. This does also neutralize the acid at the same time as acids that are utilized in market and may be disposed of, they should be neutralized. This also is going for any acid spill.