If hydrogen were used as a fuel, it could be burned according to the following reaction:
H2(g) + 1/2O2(g) > H2O(g).
A) Use average bond energies to calculate ΔHrxn for this reaction.

The equation below shows the reaction of zinc with hydrochloric acid (hcl). zn (s) + 2 hcl (aq) —> zncl2 (aq) + h2 (g) what will happen if the concentration of hcl is decreased? a. more zncl2 will be produced. b. the reaction rate will slow down. c. the hydrochloric acid will become more acidic. d. the reaction will produce water instead of hydrogen gas.

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?

Why is it incorrect to balance a chemical equation by changing the subscripts? explain.