Can someone help with these 4 questions regarding a chemistry lab.

1. Use the ideal gas law to derive the combined gas law.

2. What volume should a 1.0 L balloon at 25 C and 1.00 atm pressure be if immersed in liquid nitrogen (-196 C. 1 atm; assuming no elasticity forces in the rubber)?

3. When the experiment in question 2 is actually performed, the volume of the balloon approaches 0.0 L. How do you account for the discrepancy?

4. 0.525 grams of magnesium are reacted with an excess amount of aqueous hydrochloric acid at 27 C and 752 mmHg.

a. Write the chemical equation (remember magnesium chloride is the other product).

b. Calculate the number of moles of hydrogen gas produced.

c. Calculate the volume of hydrogen gas produced.