Which of the following is an isotope of hydrogen

Why does his teacher ask him to balance the equation by including the correct coefficient

How many moles of al3+ ions are in 1.25 moles of al2o3

A5 mole sample of liquid acetone is converted to a gas at 75.0°c. if 628 j are required to raise the temperature of the liquid to the boiling point, 15.600 kj are required to evaporate the liquid, and 712 j are required to raise the final temperature to 75.0°c, what is the total energy required for the conversion?