1. Intro to chemistry
Therm o
A. A balanced equation that includes the physical states and the quantity of ______ released or absorbed as heat is known as a _____________ equation.
energy
thermochemical

2. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) + 891kJ
Intro to chemistry
Therm o
CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) + 891kJ
2SO3(g) + 198kJ → 2SO2(g) + O2(g)

3. Intro to chemistry
Therm o
1. The _______ (heat) of reaction, ΔHrxn, is the amount of ______ released or absorbed as ____ during a chemical reaction.
enthalpy
energy
heat

4. Intro to chemistry Therm o Enthalpy change
a. ________, H, is a name given to the heat content of a system (your reaction) that occurs at constant pressure. Although we cannot measure the actual enthalpy of a substance, you can measure the _______ in enthalpy, ΔHrxn ,which is the heat absorbed or released in a reaction.
change

5. Intro to chemistry
Therm o
b. This amount of heat energy absorbed or lost by a system (your reaction) is known as the -________ change, ΔHrxn. For the purposes of this course, the change in enthalpy, ΔHrxn, is the same as Q.
enthalpy

6. Intro to chemistry
Therm o
2. _____________ equations are often written by designating the ___ of ΔH rather than writing the energy as a reactant or product.
Thermochemical
sign

7. Intro to chemistry Therm o CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) + 891kJ
2SO3(g) + 198kJ → 2SO2(g) + O2(g)
CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) ΔH= -891kJ
2SO3(g) → 2SO2(g) + O2(g) ΔH=+ 198kJ

8. Intro to chemistry
Therm o
a. _______ ΔH indicate an _________ reaction. Heat is ________ into the surroundings.
Negative
exothermic
released

9. Intro to chemistry
Therm o

10. Intro to chemistry
Therm o
b. _______ ΔH indicate an __________ reaction. Heat is ________ from the surroundings.
Positive
endothermic
absorbed

11. Intro to chemistry
Therm o