Chemical Reactions. Maddie Campbell Zach Dakin Brian Sutton Emily Thompson. Physical Changes. A change in physical state Chemical substances don’t change Physical changes are reversible
Endothermic- Net energy change is the addition of energy
A melting object gains energy. It is an endothermic energy change.
* Although melting ice is a physical change- it involves a phase change of matter, it also is an energy change. It is not usually a chemical reaction.
Exothermic- Net energy change is the loss of energy
A burning object gives off energy; it loses energy. It is an exothermic energy change.
*This is a chemical reaction- see combustion and burning on “Types of Reactions Ctd.”
Synthesis- 2 or more substances combine to form one substance
Decomposition- one substance reacts to form two or more products
Combustion- the reaction of a substance with oxygen and the release of energy (exothermic)
Displacement- When a more reactive element replaces a less reactive element in a compound
Single Displacement- When one element is exchanged between the reactants
Double Displacement- elements are exchanged between the reactants
Ionic Precipitation- The production of an insoluble solid from the reaction of 2 or more compounds
Acid-Base Neutralization- in general, the reaction of an acid and a base to produce a salt and water
Remember OIL RIG! Oxidation Reduction
Is the Is the
Loss of electrons Gain of electrons
Electrolysis- A reaction in which ions move towards electrodes due to an electrical current
Catalyst- A substance which increases the rate of a chemical reaction but itself remains unchanged at the end of the reaction
List what type the following reactions are:
1) NaOH + KNO3 -> NaNO3 + KOH
2) CH4 + 2 O2 -> CO2 + 2 H2O
3) 2 Fe + 6 NaBr -> 2 FeBr3 + 6 Na
4) CaSO4 + Mg(OH)2 -> Ca(OH)2 + MgSO4
5) NH4OH + HBr -> H2O + NH4Br
6) Pb + O2 -> PbO2
7) Na2CO3 -> Na2O + CO2
8) What is a physical change?
9) Give two examples of physical changes
10) What is a chemical change (reaction)?
1) double displacement
3) single displacement
4) double displacement
8) A physical change is a change in physical state; it does not change the chemical substance and is easier to reverse than a chemical reaction.
9) Including, but not limited to: melting ice, adding carrots to a salad, and putting ketchup on a burger
10) A chemical change/reaction changes old substances into new and is very difficult to reverse. It involves a change in energy.