Enthalpy

N2 (g) + 2O2 (g) --> 2NO2 (g) ΔH = +68kJ *What does the ΔH mean in this case?*

68 kJ of energy gets absorbed for the reaction to occur as written (per mole of N2)

N2 (g) + 2O2 (g) --> 2NO2 (g) ΔH = +68kJ *This reaction is (endothermic/exothermic)?*

endothermic

In an *exothermic* reaction, _____ is converted into ____.

enthalpy; heat

Mg (s) + 2HCl (aq) --> MgCl2 (aq) + H2 (g) ΔH = -1280kJ *This reaction is (endothermic/exothermic)?*

exothermic

In an *endothermic* reaction, _____ is converted into ____.

heat; enthalpy

In an *exothermic* reaction, the potential energy of the products is (less/more) than the potential energy of the reactants.

less

In an *endothermic* reaction, the potential energy of the products is (less/more) than the potential energy of the reactants.

more

The ΔH in an *exothermic* is (negative/positive).

negative

Mg (s) + 2HCl (aq) --> MgCl2 (aq) + H2 (g) ΔH = -1280kJ *What does the ΔH mean in this case?*

1280 kJ of energy gets released when the reaction occurs as written (per mole of Mg).

What is activation energy (Ea)?

Energy input is necessary for the reaction to occur. The energy "hill" the reactants need to get over before they can react.

Mg (s) + 2HCl (aq) --> MgCl2 (aq) + H2 (g) ΔH = -1280kJ *What is another way to write this reaction?*

Mg + 2HCl --> MgCl2 + H2 + 1280 kJ

N2 (g) + 2O2 (g) --> 2NO2 (g) ΔH = +68kJ *What is another way to write this reaction?*

N2 + 2O2 + 68 kJ --> 2NO2

What is ΔH?

The difference in enthalpy between the products and reactancts

Define enthalpy.

The heat content of a substance, or the energy state of a substance.

The ΔH in an *endothermic* is (negative/positive).

positive

In an *exothermic* reaction, heat can be thought of as a _____.

product

In an *endothermic* reaction, heat can be thought of as a _____.

reactant