Which two substances are covalent compounds?
(1) c6h12o6(s) and ki(s)
(2) c6h12o(s) and hcl(g)
(3) ki(s) and nacl(s)
(4) nacl(s) and hcl(g)

What are scientists who study fossils called? ( a ) astronomers. ( b ) biologists. ( c ) geologists. ( d ) paleontologists.

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)

Is the flow of energy during vaporizing more like the flow during melting or during freezing