Need some help on Chemistry Homework!

1. 0.5 M HCl is available for a reaction that needs 3.4 g HCl. How many liters of solution will be needed for this reaction?

2. What is the molality of a solution made up of 40g of Br2 in 4kg of water?

3. Industrial gas exhaust contains 22g of nitrogen dioxide, 30g of oxygen, and 48g of carbon dioxide for every 100g of exhaust. What is the mole fraction for each gas?