PV = nRT
P = (nRT)/V
P = (0.3 mol × 0.08206 atm-l/(mol-K) × (273.15 + 30) K)/(0.5 l)
P = 14.9258934 atm
According to the law of conservation of mass, the mass of reactants will be equal to the mass of the products. The mass of products and reactants will only differ during a nuckear reaction
Changing of the physical state of water is not a nuclear reaction. So becoz of that the mass will remain constant without any change.
2Fe + 3Cl₂ ---> 2FeCl₃
4.4mol of Fe, you have a 2:3 ratio of Fe to Cl₂ so divide 4.4/2 = 2.2 and multiply by three 2.2 x 3 = 6.6mol of Cl₂
hope that helps :)
Both aluminum and chlorine have known charges, which are +3 and -1 respectively. To make them cancel each other out in charge, you would need 3 chlorine and for one aluminum, therefore

would be correct