What mass of natural gas (CH₄) must burn to emit 267 kJ of heat? CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g) ΔH°_rxn = –802.3 kJ

Determine whether each process is exothermic or endothermic and indicate the sign of ΔH. a. natural gas burning on a stove b. isopropyl alcohol evaporating from skin c. water condensing from steam Indicate the sign of ΔH for the following processes.

The propane fuel (C₃H₈) used in gas barbeques burns according to the thermochemical equation: C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(g) ΔH°_rxn = –2044 kJ If a pork roast must absorb 1.6×10³ kJ to fully cook, and if only 10% of the heat produced by the barbeque is actually absorbed by the roast, what mass of CO₂ is emitted into the atmosphere during the grilling of the pork roast?

Nitromethane (CH₃NO₂) burns in air to produce significant amounts of heat. 2 CH₃NO₂(l) + 3/2 O₂(g) → 2 CO₂(g) + 3 H₂O(l) + N₂(g) ΔH°_rxn = –1418 kJ How much heat is produced by the complete reaction of 5.56 kg of nitromethane?

Titanium reacts with iodine to form titanium(III) iodide, emitting heat. 2 Ti(s) + 3 I₂(g) → 2 TiI₃(s) ΔH°_rxn = –839 kJ Determine the mass of titanium that react if 1.55×10³ kJ of heat is emitted by the reaction.

Determine whether each process is exothermic or endothermic and indicate the sign of ΔH. a. dry ice evaporating b. a sparkler burning c. the reaction that occurs in a chemical cold pack used to ice athletic injuries