Zinc metal reacts with hydrochloric acid (HCl) to produce hydrogen gas. What best describes this reaction?

Given that the molar mass of nano3  is 85.00  g/mol, what mass of nano3  is needed to make 4.50  l of a 1.50  m nano3solution? use  .6.75 g18.9 g255 g574 g

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.

Given the following at 25c calculate delta hf for hcn (g) at 25c. 2nh3 (g) +3o2 (g) + 2ch4 (g) > 2hcn (g) + 6h2o (g) delta h rxn= -870.8 kj. delta hf=-80.3 kj/mol for nh3 (g), -74.6 kj/mol for ch4, and -241.8 kj/mol for h2o (g)