deck chem

Question 1

What are Dispersion Forces?

Answer 1

Weakest intermolecular force; present in all molecules, especially nonpolar ones.

Also known as London Forces.

Question 2

What are Dipole-Dipole Interactions?

Answer 2

Occurs in polar molecules with permanent dipoles.

These interactions are stronger than dispersion forces.

Question 3

What is Hydrogen Bonding?

Answer 3

Stronger than dipole-dipole interactions; occurs when H is bonded to N, O, or F.

This type of bonding significantly affects the properties of substances.

Question 4

How do stronger intermolecular forces affect boiling and melting points?

Answer 4

Stronger IMF leads to higher boiling and melting points.

Question 5

What is the relationship between intermolecular forces and vapor pressure?

Answer 5

Higher IMF results in lower vapor pressure.

Question 6

Describe the characteristics of a solid.

Answer 6

Fixed shape & volume, high density, incompressible.

Question 7

Describe the characteristics of a liquid.

Answer 7

No fixed shape, fixed volume, moderately compressible.

Question 8

Describe the characteristics of a gas.

Answer 8

No fixed shape or volume, low density, highly compressible.

Question 9

What is Viscosity?

Answer 9

Resistance to flow; stronger IMF increases viscosity.

Question 10

What is Surface Tension?

Answer 10

The tendency of a liquid’s surface to resist external force.

Question 11

What is vapor pressure?

Answer 11

The pressure exerted by a vapor in equilibrium with its liquid.

Question 12

Fill in the blank: Higher IMF → ________ Vapor Pressure.

Answer 12

Lower

Question 13

Fill in the blank: Higher Temperature → ________ Vapor Pressure.

Answer 13

Higher

Question 14

What are endothermic reactions?

Answer 14

Reactions that absorb heat; examples include melting, vaporization, sublimation.

Question 15

Give an example of an endothermic reaction.

Answer 15

Ice melting absorbs heat.

Question 16

What are exothermic reactions?

Answer 16

Reactions that release heat; examples include freezing, condensation, deposition.

Question 17

Give an example of an exothermic reaction.

Answer 17

Water freezing releases heat.

Question 18

How does atmospheric pressure affect boiling point?

Answer 18

Lower atmospheric pressure → Lower boiling point; Higher atmospheric pressure → Higher boiling point.

Question 19

What occurs in the flat regions of heating and cooling curves?

Answer 19

Phase changes occur; energy breaks IMF rather than increasing temperature.

Question 20

What happens in the sloped regions of heating and cooling curves?

Answer 20

Temperature increases as energy is added.

Question 21

Define Kinetic Energy (KE).

Answer 21

Energy of motion.

Question 22

Define Potential Energy (PE).

Answer 22

Stored energy in chemical bonds.

Question 23

What is Chemical Potential Energy?

Answer 23

Energy stored in chemical bonds.

Question 24

Convert 1 calorie (cal) to Joules (J).

Answer 24

1 cal = 4.18 J.

Question 25

Convert 1 kcal (Cal) to calories (cal).

Answer 25

1 kcal = 1000 cal.

Question 26

How many calories are in a soda with 200 Cal?

Answer 26

200,000 cal or 836,000 J.

Question 27

What is the First Law of Thermodynamics?

Answer 27

Energy is conserved; cannot be created or destroyed.

Question 28

What is the Second Law of Thermodynamics?

Answer 28

Entropy (disorder) of the universe increases in spontaneous processes.

Question 29

What characterizes exothermic reactions?

Answer 29

Heat is released into the surroundings; example: combustion reactions.

Question 30

What characterizes endothermic reactions?

Answer 30

Heat is absorbed from the surroundings; example: ice melting.

Question 31

What is Heat Capacity?

Answer 31

The amount of heat required to change a substance’s temperature.