general science

physical change

change in shape, size, or physical state of matter but not its composition

chemical change

change in the composition of matter as a result due to chemical reaction

physical change

• change of phases or states

• dissolution process 

• change in physical properties

chemical change

• formation of new substances 

• evolution of gas (formation of bubbles) 

• change in temperature 

• evolution of energy

chemical reaction

a process where reactants are transformed into other substances called products

indication of chemical reaction

• change in color 

• change in temperature

• formation of an odor

• formation of a gas

• formation of a solid/precipitate

chemical equation

• is a written representation of a chemical reaction

• chemical reactions are represented by this 

  • left = reactants 

  • right = products

separates reactants or products

separates reactants from products; produces, forms, yields

reversible reactions

substance is in solid state

substance is in liquid state

substance is in gaseous state

substance is in aqueous state

evolution of gas instead of (g)

formation of precipitate instead of (s)

application of heat

catalyst used in the reaction

combination reaction

• synthesis reaction 

• involves 2 or more reactants forming a single product

• A + B > AB

A + B > AB

combination reaction

decomposition reaction

• reverse of combination reaction 

• compound is broken down into two smaller substances 

• may be initiated by heat, light, electricity of catalysts

• AB > A + B

AB > A + B

decomposition reaction

monoatomi

carbonates

are decomposed to carbon dioxide (CO2) and metal oxide

chlorates

are decomposed to oxygen gas (O2) and metal chloride

single replacement reaction

• an element replaces another element in a compound

• the reaction yields a compound and a replaced element

A + BC > AC + B

single replacement reaction

double replacement reaction

• occurs when two compounds react to from two new compounds 

• the reactants are ionic compounds that simply exchange ion partners

• AB + CD > AD + CB

AB + CD > AD + CB

• double replacement reaction

• AC are positive ions, BD are negative ions

combustion reaction

• when fuels (hydrocarbon) reacts in the presence of oxygen gas (O2) producing an immense amount of energy causing its products, carbon dioxide and water, coexist in steam from creating smoke

CH + O2 > CO2 + H2O

combustion reaction

solution

• homogenous mixture of two or more substances 

• composed of solute and solvent

solute

minor component

solvent

major component

solid solutions

• solvent is in solid state 

• mostly found in alloys 

liquid solutions

• solvent is in liquid state

gaseous solutions

• solvent is in gas state

globally harmonized system of classification and labelling of chemicals ghs

classifies chemicals based on the type of hazard they pose with the use of universally recognized symbols

oxidizers

flammable

explosives

acutely toxic (severe)

burns skin

gases under pressure

carcinogen

toxic to aquatic environment

acutely toxic (harmful)