Principles of Chemistry: Midterm 1

For the first midterm exam of Principles of Chem I

Mixtures

A physical combination of two or more pure substances

Pure Substance

A substance with a constant chemical composition and distinguishing properties

Property

Something that makes a sample of matter unique

vapor-pressure curve

Graph showing the relationship between vapor pressure and temperature for a substance. As temperature increases, vapor pressure also increases.

Vapor Pressure

The pressure exerted by the vapor phase of a substance in equilibrium with its liquid or solid phase at a given temperature; it increases with temperature.

Triple-Point

The temperature and pressure at which a substance can exist in all three phases (solid, liquid, and gas) simultaneously.

Supercritical Fluid

A state of matter where a substance is above its critical temperature and critical pressure, exhibiting properties of both a gas and a liquid.

Critical Point

The point of pressure and temperature where a supercritical fluid begins to form

Relation between pressure and water's melting point

Higher pressures decrease melting point

Pressure and Melting Point

As pressure increases, so does the melting point of most substances

Distillation

Process of separating a mixture of liquids based on their different boiling points. Mixture is heated, and the liquid with the lower boiling point vaporizes first. The vapor is then cooled and condensed back into a liquid, resulting in the separation of the components.

Crystallization

Process of solid particles forming a crystal lattice structure through cooling or evaporation of a solvent, resulting in the formation of a solid crystal.

Basic Assumption for Substances

An underlying belief about substances that guides scientific research and understanding. It assumes that substances have specific and unique properties and behaviors that can be studied and explained through experimentation and observation.

Particulate Model of Matter

Theory explaining the behavior of matter at the particle level. It states that all matter is made up of tiny particles that are constantly moving and have space between them. These particles have different properties and interact with each other through forces. This model helps explain various phenomena like changes in state, diffusion, and mixing of substances.

Ideal Gas

A gas that follows the ideal gas law, PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature.

Ideal Gas Law

PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. It describes the behavior of an ideal gas at a given state.

Ideal Gas Constant

The universal constant that relates the pressure, volume, and temperature of an ideal gas is known as the ideal gas constant. It is denoted by the symbol R and has a value of 8.314 J/(mol·K).

Ideal Gas Constant

Value of the constant (R) used in the ideal gas law equation PV = nRT. It is equal to 0.0821 L·atm/(mol·K).

Dynamic Nature of Particles

Particles exhibit dynamic nature, constantly moving and interacting with their surroundings. They possess kinetic energy, causing them to vibrate, rotate, and translate. This motion is influenced by factors like temperature and pressure. Additionally, particles can undergo phase changes, transitioning between solid, liquid, and gas states.

Impact of Mass on Particle Speed

As mass increases, particle speed decreases.

What is the Ideal Gas Equation?

PV=nRT

If I were trying to find the pressure of an ideal gas, what formula would I use?

P=nRT/V

Your cousin Throckmorton needs to find the temperature in Kelvin of an ideal gas. What equation should he use?

T=PV/nR

Water Break! Drink some water

Yes ma’am

Real Gas Model

A mathematical model used to describe the behavior of gases that deviate from ideal gas behavior. It takes into account factors like intermolecular forces and molecular size.

How to find "n" in the Ideal Gas Formula

The Ideal Gas Formula is PV = nRT. To find "n," divide the given pressure (P) and Volume (V) by the ideal gas constant (R) multiplied by the given temperature (T) in Kelvin. (n=PV/RT)

Potential Energy

Energy stored in a system of interacting particles (how likely those particles are to move around and shit)

Kinetic Energy formula

½ (MV)², where M=Mass and V=Volume

When particles are super far apart, what is their potential energy

Ep=0

During a phase change, what increases?

Potential Energy

What is a configuration?

A tool that helps us make predictions about processes and the state of matter. It is usually a grid with dots in it.

You are doing such a great job! I am so proud of you!

I am doing a great job! I’m so smart!

What does “n” stand for in the Ideal Gas Equation

Number of mols of gas