Unit 3 (chapter 5)

Question 1

Thermochemistry

Answer 1

The study of the energy changes that accompany chemical, physical or nuclear changes in matter

Question 2

Energy

Answer 2

The capacity to do work (joules)

Question 3

Kinetic energy

Answer 3

Energy due to motion of an object, vibration of atoms

Rotation of translation of molecules within a substance

Question 4

Potential energy

Answer 4

Energy due to position, elecytic potential energy of atoms connected by bonds

Question 5

Thermal energy

Answer 5

A form of kinetic energy that results from the motion of particles

Question 6

Heat

Answer 6

The transfer of thermal energy to a warmer to a cooler object

Question 7

Temperature

Answer 7

The average kinetic energy possessed by a molecule within a substance

Question 8

Chemical system

Answer 8

A group of reactants and products

Question 9

Surroundings

Answer 9

All the matter around the system that is capable of absorbing or releasing energy

Question 10

Open system

Answer 10

A system where both matter and energy are free to both enter and leave the system

Question 11

Closed system

Answer 11

Energy can enter and leave the system but matter cannot ex. closed jar of boiling water

Question 12

Isolated system

Answer 12

An ideal system which neither matter or energy can move in or out

Question 13

Endothermic

Answer 13

Absorbing energy from the surroundings in order to create products +delta H

Question 14

Exothermic

Answer 14

Releasing energy to the surroundings - delta H

Question 15

Calorimetry

Answer 15

Process of measuring energy changes in a chemical system

Question 16

Enthalpy change

Answer 16

The energy absorbed or released to the surroundings when a specific chemical change occurs in a chemical system

Question 17

Molar enthalpy

Answer 17

The energy change associated with one mole of a substance undergoing a specific change

Question 18

Hsol

Answer 18

Solution

Question 19

Hvap

Answer 19

Vaporization

Question 20

Hfr

Answer 20

Freezing

Question 21

Hneut

Answer 21

Neutralization

Question 22

Hf

Answer 22

firmation

Question 23

Hsys

Answer 23

= n (deltaHx) or q/n

Question 24

Assumption for calorimeters

Answer 24

• No heat is transferred to the outside environment
• Any heat absorbed by the calorimeter is negligible
• A dilute (aq) solution is assumed to have the same density and specific heat capacity as water (c=4.18J/gc)

Question 25

Hx

Answer 25

molar enthapy

Question 26

Thermochemical equation

Answer 26

Add number in chemical equation (Left side= endothermic, right side= exothermic)

Question 27

Chemical equation and starting H

Answer 27

H is off to the side

Question 28

Stating molar enthalpy of the reaction

Answer 28

Hdecomp= 285 kJ/mol H2O

Question 29

Chemical potential energy diagram

Answer 29

y= ep(kj)

x= rxn progress

Question 30

Hess’s law

Answer 30

1) If a chemical equation is reversed the sign of delta H changes
2) If the coefficients of a chemical system are altered by multiplying of diving by a constant factor, then the delta H is altered the same way
3) Formulas cancelled from both sides of an equation much be for the same substance in the same state

Question 31

Enthalpy change without using hess’s law

Answer 31

Sum of products- sum of reactants