Use Hess’s Law to calculate the heat of reaction for the following reaction: 2H2O2 → 2H2O +O2 ∆H=?
2H2 +O2 → 2H2O ∆H=-572 KJ
2H2O2 → 2H2 + 2O2 ∆H=376 KJ

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )