Chapter 5 (Thermochemistry)

Question 1

What is a Calorimetry?

Answer 1

A technique used to measure the amount of heat involved in a chemical or physical process. (Heat transferred from substance to substance).

Question 2

What is Thermal Chemistry?

Answer 2

The study of heat flow in chemical reactions.

Question 3

What is Energy?

Answer 3

The capacity to do work.

Question 4

What is Heat (q)?

Answer 4

A particular form of energy that is transferred from a body at high temperature to a body at low temperature.

Question 5

What is a system?

Answer 5

The part of the universe being studied.

Question 6

What is surrounding?

Answer 6

The rest of the universe. (A practical stand point, normally the materials in contact with the system).

Question 7

What does state refer to?

Answer 7

A description of the composition, temperature, and pressure of the system.

Question 8

T/f, the state properties depend on the current state of the system, not the past history.

Answer 8

True.

Question 9

Heat (q) is positive when?

Answer 9

When heat is added to the system.

Question 10

Heatlq) is negative when?

Answer 10

When heat flows out of the system is taken away from the system ).

Question 11

An endothermic process is?

Answer 11

One which heat flows from the surrounding to the system. “Endo” sounds like into.

Question 12

An exothermic process is?

Answer 12

A process in which heat flows from the system to the surroundings. (Exo = out of).

Question 13

Define heat capacity (C).

Answer 13

The amount of energy needed to raise the temperature of the system by 1°C.
(Units for C = J/°C).

Question 14

Heat is normally measured in what units?

Answer 14

Joules (J) or kJ (1000 J=1 kJ).

Question 15

Heat flow and temperature are related in what formula?

Answer 15

Heat (q) = C * chngT (chngT = Tfinal-Tinitial)

Question 16

What is specific heat capacity (c)?

Answer 16

The amount of heat energy needed to raise the temperature of the system by 1° C. (This is an extensive property as it depends on the amount of material present)

Question 17

What are specific heat capacity units?

Answer 17

J/ g°C

Question 18

Q(rxn) = - q(cal) is referring to?

Answer 18

The prevention of heat exchanged with the surrounding.
Q(rxn) = -C(cal) * chngT
C(cal) = m(water) * c(water)

Question 19

What is enthalpy? (or heat content)?

Answer 19

The relation of bonds being broken or formed.
Q (vyn) = chngH
ChngH = H(products) - H(reactants)