Term | Definition |
Thermochemistry | The branch of chemistry pertaining to TEMPERATURE CHANGES and HEAT TRANSFER of both physical processes and chemical reactions. |
Heat (Delta H) | A measure of both the speed & quantity of particles (total energy) measured in Joules (J) heat is transferred from a warmer object to a cooler object |
Heating + Cooling curves | The nature of water. Water has the chemical formula H2O and has a bent molecular structure, resulting in the molecule being POLAR. |
Why are water molecules attracted to one another? | Due to polarity (Hydrogen bonds) |
Water heating curve (s) | -100 - 0 |
Water heating curve (s-> 1) melting | 0-0 |
Water heating curve (1) | 0->100 |
Water heating curve (1->g) boiling | 100-100 |
Water heating curve (g) | 100->200+ |
Water cooling curve (g) | 200-100 |
Water cooling curve (g->1) condensing | 100->100 |
Water cooling curve (1) | 100->0 |
Water cooling curve (1->s) freezing | 0->0 |
Water cooling curve (s) | 0-> -100 |
Melting & Freezing | Delt.H - HfusM |
Boiling and Condensing | Delt.H = HvapM |
Heating & Cooling | Delt.H=mcDelt.T |
Delta H | Heat (J) |
Hfus | Heat of fusion (J/G) |
Hvap | Heat of vaporization (J/g) |
M | Mass (g) |
C | Specific heat capacity (J/g C) |
Delta T | Temperature change (Final tmp - initial temp) |
Endothermic reaction | Delt.H is written as a reactant ; positive |
Exothermic reaction | Delt. H is written as a product ; negative |
Heat of reaction | The amount of energy released or absorbed by a chemical reaction |
Enthalpy | at constant, pressure the heat of reaction |
delta H | The total energy of bonds broken - total energy of bonds formed |
heat of formation | heat released or absorbed when one mole of a compound is formed by a combo of its elements |
heat of a reaction is also.. | the total of heats of formation of products minus the heats of the formation of the reactants |
steps need to be reversed sometimes... | can be multiplied by a constant or a step can be reversed |
if step multiplied by a # | DELTA H is also multiplied by that number |
if step is reversed | the sign of delta h is also reversed |