Find ΔHrxn for the reaction: 3 H2(g) + O3(g)S3 H2O(g) Use these reactions with knownΔ H ’s: 2 H2(g) + O2(g)h2 H2O(g) ΔH = -483.6 kJ 3 O2(g)h2 O3(g) ΔH = +285.4 kJ 6.9

Adozen is 1221/12 = 1.751.75 x 12 = 21therefore, 1.75 is the answer.

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water