In which equation does the term "heat" represent heat of fusion? (1) nacl(s) heat --> nacl(l) (2) naoh(aq) hcl(aq) --> nacl(aq) h2o(l) heat (3) h2o(l) heat --> h2o(g) (4) h2o(l) hcl(g) --> h3o (aq) cl-(aq) heat

1) which of the following is the best example of a physical change? a) sugar dissolving in tea b) firefly glowing 2) in the combustion of ethane, what is/are the reactants? c2h6 + o2 ==> co2 + h2o a) c2h6 and o2 b) co2 and c2h6