Which reactions are exothermic?   Reaction 1: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) + 2220 kJ   Reaction 2: 4 H2(g) + 2 O2(g) → 4 H2O(l) + 1140 kJ   Reaction 3: 2 H2O(l) + 88 kJ → 2 H2(g) + O2(g)   Reaction 3 Reactions 2 and 3 Reaction 1 and 2 All reactions are since they produce products.

Determine the heat involved in the combustion of liquid hydrazine by using the following reactions. 2NH3(g) + 3N2O(g) → 4N2(g) + 3H2O(ℓ)      ΔH°= –1013 kJ/molN2O(g) + 3H2(g) → N2H4(ℓ) + H2O(ℓ)      ΔH°= –317 kJ/mol2NH3(g) + ½O2(g) → N2H4(ℓ) + H2O(ℓ)      ΔH°= –142.9 kJ/molH2(g) + ½ O2(g) → H2O(ℓ)       ΔH°= –285.8 kJ/mol Then, Launching a small spacecraft to study Jupiter required approximately 28 million kJ. Assume that hydrazine was the only fuel. What mass of hydrazine, in kilograms, was needed for the launch?

Consider the following reaction.  CH4 + 2O2 -> 2H2O + CO2      ΔH = -890 kJ/mol If 45 g of methane combust, then what amount of energy is released?

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