Post on 18-Jan-2018
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CHEMICAL AND PHYSICAL
REACTIONS
PHYSICAL PROPERTIES A characteristic of matter that can be
observed without changing the substance into another substance
Examples: Freezing Boiling Melting Hardness Color Shine flexibility Solubility
CHEMICAL PROPERTIES Characteristics of a substance that describe
its ability to change into a new substance
Examples: Burning Rusting Tarnishing
Changing into a new substance requires another chemical, like O2 changing to CO2
PHYSICAL AND CHEMICAL PROPERTIES ACTIVITY Using the objects provided, list the physical
and chemical properties of each object
Create a table to classify each object based on its properties
Use the equipment & substances available
A: Match B: Crayon C: Metal Ring
D
Reacts with waterDoes not reactFlammableNonflammableHardSoftMelts at room temp
EvaporatesPhysical Properties or Chemical Properties
Metallic, non-metallic, magnetic, heat conductor
PHYSICAL AND CHEMICAL PROPERTIES ACTIVITY 2 Using the substance provided, investigate
and report on its chemical and physical properties
Use your Lab Book, create a table with Physical and Chemical Properties noted
PHYSICAL CHANGES The form or appearance of a substance is
altered, without combining it with another substance
Examples?
Ice to water to steam Ice cream melts Make Kool-aid Cut paper
Reversible!!!
CHEMICAL CHANGES A change in matter that results in one or more
new substances
Chemical in the original substance combines with another chemical to create a new substance
Examples? Burning anything Baking cookies Fireworks
Not reversible!!!
EVIDENCE OF CHEMICAL REACTIONS Color change
Heat given off/absorbed
Change in odor
Gas released
Light given off
CHANGES IN ENERGY Is energy released/taken in during a physical
or chemical change?
Energy can be light, heat, or sound
If heat energy is removed during a reaction, it is an exothermic reaction (feels hot)
If energy is added during a reaction, it is an endothermic reaction (feels cold)
COMMON CHEMICAL REACTIONS Photosynthesis
Co2 + H2O = C6 H12 O6 + O2
Respiration O2+ H2O = Co2 + H2O
Combustion
Rusting
MINI-LAB! Determine whether each reaction is
endothermic or exothermic
Make hypotheses for each of the following: Strike a match Vinegar and antacid
Write 3 observations for each
Write a one sentence conclusion for each
RATES OF CHEMICAL REACTIONS How quickly a chemical reaction can take
place
Controlled by 4 things Surface Area Temperature Concentration Substances
Catalysts Inhibitors
REACTANTS AND PRODUCTS Reactants are combined together to create
products
What are the reactants and products in the following equations? C + 2 O CO2 2 H + O H2O
What do you notice about these equations? There are the same number of atoms on the left as
on the right Coefficients, subscripts
BALANCING EQUATIONS Goal- Have the same number of atoms on
both sides of the equation.
Rules Coefficients multiply You can not change subscripts If there is no subscript after an atom, then you
know there is only 1 atom present
Examples on board Practice worksheet