finding masses of reactants in a given volume with a given density

i have a headache of a chem problem (actually 5 headaches)

1. Magnesium reacts with HCl. Given the information below, what is the amount of Mg and HCl needed to do this reaction to fill a flask that holds 1 L?
Mg has a density of 1.74g/ml and 1 g of Mg requires 30.6 mL of an acid solution to react completely.

2. A sample of an organic compound (27.08g) was burnt in oxygen. The carbon dioxide formed weighed 53.31g and the water formed weighed 32.57g. what is the percent composition and empirical formula for the compound?

3. A compound X has the elemental composition of 92.3% C and 7.7% H. If 1.65g of X is converted to vapor it occupies 561 mL at 150.0 degrees Celcius and 0.961 atm. Whst if the empirical and molecular formulas for compound X?

4. 100.00g of water was placed in a calorimeter. The calorimeter has a calorimeter constant of 9.85J/Kelvin. The initial temperature of the water and calorimeter was 25.66 degrees celcius. 10.00g of ice at 0.00 degrees celcius were added. after all the ice melted, the final temperature was 16.30 degrees celcius.
a. set up the calorimeter equation for all processes occuring in the calorimeter. define each q
b. calculate the heat of fusion for the ice. I.E. how much heat was absorbed due to the 10g of ice melting?
c. calculate the heat of fusion per mole of ice.

SOMEONE PLEASE HELP ME OUT!!! WE HAVENT EVEN GONE OVER HALF THE MATERIAL THAT HE IS REQUESTING US PERFORM!!!

THANKS!!!

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