Which of the equations below is an example of a thermochemical equation?
O 2 H2 (g) + 2 02 (g) --> H20 (g)
O 2 H2 (g) + 2O2 (g) --> H20 (g) + 483.6 kJ
O Mg + 2 H3O+ + Cl --> Mg2+ + 2C1 + H2+ H20
0 Mg (s) + 2 H3O+ (aq) --> Mg4+ (aq) + 2 H2(g) + H2O (1)

The diagram below shows the different phase transitions that occur in matter. which arrow represents the transition in which dew is formed?

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.

State one important difference between a physical change and a chemical change?