science test (december 2024)

Collision Theory

Particles must collide with the right orientation and energy for a reaction to occur

3 things for collision theory

Correct orientation, particles must collide, and sufficient energy

Increase of temperature in a reaction

Increases the rate of reaction by increasing the frequency and energy of collisions

How is pressure and concentration the same conceptually?

Both relate to the number of particles in a given space

Definition of Activation Energy

The minimum amount of energy required for a chemical reaction to occur

Factors that affect the rate of chemical reactions

Temperature, concentration/pressure, surface area, catalyst (presence or absence)

Solid particle diagram

Tightly packed

Liquid particle diagram

Close together, but not tight

Gas particle diagram

Far away and not packed

Affect of pressure on a reaction

Increases or decreases collison

Affect of temperature on a reaction

Provides activation energy

Affect of volume on a reaction

Increases or decreases collision

Affect of the number of particles on a reaction

Increases or decreases collision

Conversion from C to Kelvin

C + 273

Characteristics of an Ideal Gas

Molecules are moving fast and random, have no volume, do not attract or repeal each other, elastic collisions, temperature of the gas is proportional to the average kinetic energy

Definition of elastic collisions

No kinetic energy is lost when gas molecules collide with each other

Characteristics of a Real Gas

Under a low temperature and high pressure, they move in straight lines between collisions, take up volume, and are attracted to each other under conditions.

Difference between real gases and ideal gases

Real gases do not follow gas laws for all values of temperature and pressure

Ideal Gas Law meaning

Under the same temperature, pressure, and volume all gases contain the same number molecules but not the same.

Charles Law

V1/T1=V2/T2

Charles Law meaning

Describes how gases tend to expand when heated

Lab for Charles Law

Balloon lab

What changes the rate of reaction

Changes with a catalyst, temperature, pressure, and surface area.

A higher temperature equals

A higher rate of reaction

Lab for temperature rate of reaction

Disappearing X

Endothermic

Absorbs heat

Exothermic

Releases heat

Examples of Endothermic reactions

Melting of ice, photosynthesis, water evaporation, reaction between vinegar and baking soda, gas burning, ice pack

Examples of Exothermic reactions

Combustion reactions, formation of snow, neutralization reactions (bases and acids), rusting, hot pack

Characteristics of Endothermic reactions

Is cooler than the surroundings

Characteristics of Exothermic reactions

Is hotter than the surroundings

What degrades an enzyme?

Temperature or pH (Acidic environment)

Rate of reaction equation

Reactant lost/Time or Product/Time