Unit 10 - Thermochemistry

Question 1

Thermochemistry

Answer 1

The study of energy changes during a chemical reaction or change of state (solid, liquid, gas).

Question 2

Chemical Potential Energy

Answer 2

The energy stored in chemical bonds. (Lines with no Slope on the Heating Curve)

Question 3

Heat

Answer 3

Energy that transfers from one object to another due to a difference in temperature between them. Heat always flows from the warmer to the cooler object.

Question 4

Calorimeter

Answer 4

The device used to measure the quantity of heat flow in a reaction.

Question 5

Calorimetry Steps

Answer 5

1. Use a well known substance (water) 2. Run the reaction and let heat go into or out of the water 3.Measure the waters change in temperature

Question 6

The heat lost in a reaction (Q lost) = ?

Answer 6

Q lost = Q gained

Question 7

Melting

Answer 7

Make or become liquefied by heat. (Solid to Liquid)

Question 8

Freezing

Answer 8

Freezing or solidification is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. (Liquid to Solid)

Question 9

Condensation (Precipitation)

Answer 9

The conversion of a vapor or gas to a liquid.

Question 10

Vaporization (Evaporation)

Answer 10

The conversion of a liquid into a gas.

Question 11

Heat of Fusion

Answer 11

The energy required to change a gram of a substance from the solid to the liquid state without changing its temperature.

Question 12

Solidification

Answer 12

Freezing or solidification is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. (Liquid to Solid)

Question 13

Heat

Answer 13

A form of energy that flows between two samples of matter because of their differences in temperature.

Question 14

Temperature

Answer 14

A measure of the intensity of heat, i.e. the hotness or coldness of a sample. or object.

Question 15

Kinetic Energy

Answer 15

In Thermochemistry, the energy an object possesses due to its change in temperature is called kinetic energy. (Sloped lines on the Heating Curve)

Question 16

Potential Energy

Answer 16

Potential energy is that energy which an object has because of its position. It is called potential energy because it has the potential to be converted into other forms of energy, such as kinetic energy. (Lines with no Slope on the Heating Curve

Question 17

Endothermic

Answer 17

Reaction in which the system absorbs energy from its surroundings in the form of heat.

Question 18

Exothermic

Answer 18

An exothermic reaction is a chemical reaction that releases energy in the form of light or heat.

Question 19

Collision Theory

Answer 19

Molecules have to collide in a certain way with a certain amount of activation energy in order to form a new product.

Question 20

Activation Energy

Answer 20

The minimum energy required to start a chemical reaction

Question 21

How to speed up the Rate of a Reaction

Answer 21

1. Shrink the container or increase concentration. 2. Increase the number of particles. 3. Speed up the particles by adding heat. 4. Break up clumps into individual particles. 5. Use a catalyst.

Question 22

Catalyst

Answer 22

A substance that causes a chemical reaction to happen more quickly.

Question 23

Heating Curve

Answer 23

A plot of the temperature versus time.

Question 24

What do the symbols in the following equation represent:

Q=mC(Delta T)

Answer 24

Question 25

Solid

Answer 25

Solid is one of the four fundamental states of matter. It is characterized by structural rigidity and resistance to changes of shape or volume.

Question 26

Liquid

Answer 26

Liquid is one of the four fundamental states of matter, and is the only state with a definite volume but no fixed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds.

Question 27

Gas

Answer 27

One of four main states of matter, composed of molecules in constant random motion. Unlike a solid, a gas has no fixed shape and will take on the shape of the space available. Unlike a liquid, the intermolecular forces are very small; it has no fixed volume and will expand to fill the space available.

Question 28

Boiling

Answer 28

Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point.

Question 29

Boiling Point

Answer 29

The temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure. At the boiling point the gas and liquid phase exist in equilibrium.

Question 30

Melting Point

Answer 30

The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium.

Question 31

Phase Changes

Answer 31

Question 32

Law of Conservation of Energy

Answer 32

Energy can not be created nor destroyed during a chemical reaction

Question 33

Heat Capacity

Answer 33

Heat capacity is the amount of heat energy required to change the temperature of a substance

Question 34

Specific Heat

Answer 34

the amount of energy in the form of heat, calories or joules, required to raise the temperature of 1 gram of a substance 1°C