Thermochemistry and Energy Flashcards
6 cards from real CART practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Thermochemistry and Energy flashcards as text
Which calorimetry equation relates heat, mass, specific heat, and temperature change?
Answer: q = mcΔT
The equation q = mcΔT calculates heat by multiplying mass, specific heat capacity, and change in temperature.
In a coffee-cup calorimeter experiment, the temperature of the solution rises after mixing two reactants. The reaction is:
Answer: Exothermic
A temperature rise in the calorimeter means the reaction released heat to the solution, indicating an exothermic reaction.
The heat of combustion of propane (C₃H₈) is –2220 kJ/mol. How much heat is released by burning 0.5 mol of propane?
Answer: –1110 kJ
Multiplying 0.5 mol × (–2220 kJ/mol) = –1110 kJ, meaning 1110 kJ of heat is released.
Which symbol represents the heat of a reaction measured at constant volume?
Answer: ΔU (or ΔE)
Internal energy change (ΔU or ΔE) represents heat flow at constant volume, as measured in a bomb calorimeter.
Bond breaking in a chemical reaction requires ________ energy, while bond forming ________ energy.
Answer: absorbs; releases
Energy must be absorbed (input) to break bonds, and energy is released (output) when new bonds form.
If the products of a reaction have higher enthalpy than the reactants, the ΔH for the reaction is:
Answer: Positive
ΔH = H(products) – H(reactants); if products have higher enthalpy, ΔH is positive, indicating an endothermic reaction.