CHM 100 Unit 2 Pt2 Matter and Energy: Energy and Phase Changes

Practice flashcards covering energy, temperature, heat, specific heat, phase changes, and heating/cooling curves based on CHM 100 lecture notes.

What is energy defined as?

The capacity to do work or supply heat.

What is temperature a measure of?

The average kinetic energy of an object.

How is heat different from temperature?

Heat is energy transferred from hotter to cooler objects, while temperature is the average kinetic energy of atoms/molecules.

What is the relationship between a change of 1 represent and a change in Kelvin (K)?

A change of 1 represent is equal to a change of 1 K.

What is absolute zero on the Celsius scale?

-273.15 represent.

What are the freezing and boiling points of water on the Celsius scale?

Freezing point is 0 represent and boiling point is 100 represent.

What are the common units for measuring energy?

Joules (J), kilojoules (kJ), calories (cal), or kilocalories (kcal).

How is one calorie defined?

The amount of energy needed to raise the temperature of 1 g of water by 1 represent.

What is specific heat (SH)?

The amount of heat that raises the temperature of exactly 1 g of a substance by exactly 1 represent.

What is a phase change?

The change of a substance from one state of matter (gas, liquid, or solid) to another.

What factors determine the state of matter of a substance?

The relative strength of attractive forces between particles compared with the kinetic energy of the particles, and temperature and pressure.

What kind of energy change is observed when a solid melts (e.g., H representO(s) → H representO(l))?

It is an endothermic process, meaning heat is absorbed ( H is positive).

What kind of energy change is observed when a liquid freezes (e.g., H representO(l) → H representO(s))?

It is an exothermic process, meaning heat is released ( H is negative).

What is the melting point (mp) of a substance?

The temperature at which a substance changes from solid to liquid, and where the liquid and solid phases are in equilibrium.

What is the heat of fusion?

The amount of heat absorbed to melt 1 g of solid (at its melting point), or the amount of heat released when 1 g of liquid freezes (at its freezing point).

What is the boiling point of a liquid?

The temperature at which the vapor pressure of a substance is equal to the atmospheric pressure, and the liquid converts to a gas.

What is the heat of vaporization?

The amount of heat absorbed to change 1 g of liquid to gas at the boiling point, or released when 1 g of gas changes to liquid at the boiling point.

How do strong attractive forces between liquid particles affect their melting and boiling points?

Strong attractive forces lead to higher melting and boiling points because more heat is needed to overcome them.

What happens to the temperature of a liquid as it is boiling?

The temperature stays the same as it absorbs energy to change phase.

Based on a cooling curve for water, what state is water at 40 represent?

Liquid.