Use average bond energies to calculate delta H for the reaction of H2 and O2 to form water.

ΔHrxn = - 3294.8 KJ/mol

Explanation:

H - H                         H - O - H

H - H   +   O = O   →  H - O - H  

broken bond:

⇒ 2 bond H - H + 1 bond O = O

bond formed:

⇒ 4 bond H - O

bond energies:

∴ H - H: 436.4 KJ/mol

∴ O = O: 494 KJ/mol

∴ H - O: 482 KJ/mol

broken bond:

⇒ bond energie = 2(436.4) + 494 = 1366.8 KJ/mol

bond formed:

⇒ bond energie = 4(- 482) = - 1928 KJ/mol

⇒ ΔHrxn = - 1928 KJ/mol - (1366.8 KJ/mol)

⇒ ΔHrxn = - 3294.8 KJ/mol

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )