Chemical Reactions - Unit two

What is a chemical reaction?

• Particles have been rearranged

• When a new substance has formed

Evidence of a chemical change

• There is an unexpected change in colour.

• Energy is released or absorbed.

• A gas is produced.

• A precipitate forms.

precipitate

when a solid produces out of two liquids

Kinetic Molecular Theory

Particles are always moving no matter the state

How do particles move when no reaction occurs

• Particles will move slowly

• particles will collide but not hard enough to form new bonds

What causes particles to move faster

• Temp change allows particles to speed up bec they gained more energy

• Pressure change in gases forces particles to squeeze together allowing them to colide more often

Catalyst

• Force particles to move faster w/o a change in energy

• Don’t actually get used up in the reaction so they can keep doing as pleased

Law of conservational mass

Total mass of reactants = total mass of products

Collision reaction theory

• particles that are slow and dont hit hard enough on each other don’t form a new reaction

• Particles that are moving fast and hitting hard on each other form a new reaction

Synthesis

Smaller atoms turn into a larger more complex molecule

Is their a limit to how many reactants in a synthesis

No

Decomposition

Larger molecule = broken down smaller molecules

Metal + OH =

Metal + O2

Metal + CO

Metal Oxygen + CO2

Metal + CIO

Metal Cl + O2

Synthesis Reaction

one element replaces the other

Synthesis Metal + compound

A + BC → B + AC

Synthesis non-metal

X + BC → C + BX

Activity Series

Helps predict if a single displacement will occur

What does the activity series list

Elements most reactive (top) to least reactive (bottom)

Double displacement

When two compounds switch partners Non metals with non metals and metals with metals

When will double displacement reaction occur

when a percipitate or gas has formed or the reaction has become neutralized

Solubility chart does what

predicts which product will percipitate (s) and which will have high solubility (aq)

How do u Neutralization something and what does it produce

acid + base → salt and water

Formula for Double displacement

AB + CD → CB + AD

Signs of a Combustion

• Oxygen is a reactant.

• Heat is released.

• Often produces a flame or light.

• Forms new substances, usually carbon dioxide and water when a hydrocarbon burns completely.

What must be present for a combustion to occur

fuel, oxygen, and heat

What reaction is a combustion considered

synthesis - smaller products make a larger one

Hydrocompound contain?

Carbon and hydrogen

Properties of a Complete Combustion

• Fuel LR

• O2 ER

• known as a clean burn

Properties of a incomplete Combustion

• fuel ER

• O2 LR

• produces soot or CO

• dirty burn