If 15.6g of titanium reacts with oxygen to form 20g of titanium oxide what is the mass of oxegen

The enthalpy of formation of water is -285.8 kj/mol. what can be inferred from this statement?

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks.energy was destroyed inside the blocks.energy was absorbed into the blocks from outside the system.energy was transferred from the warmer block to the cooler block.

Which of the following is a physical property flammability heat of combustion solubility and toxicity