Chemical Changes Flashcards
Physical change
A substances physical properties change, the particles of the substance stay the same, reversible
Ex: all state changes, clay molded into a new shape, bubbles in soda
Chemical change
A new substance is formed, not reversible
Ex: baking a cake, milk goes sour, rust on a car, bread becomes toast, making a fire
What happens during a chemical reaction
Two or more molecules interact and molecules change. Bonds between atoms are broken and created to form a new molecule
Indicators of chemical change
- heat released or absorbed
- Color change
- gas released
- light
- precipitation
Factors that effect the speed of chemical reactions
- surface area of solid reactant
- concentration of pressure of reactant
- temperature
- nature of reactant
- presence or absence of a catalyst
Oxidation
Reaction with oxygen
Ex: rust, browning apple
How can you slow down the process of oxidation on an apple?
- cover in plastic
- put lemon juice on it
- put in fridge
Atom
Basic unit of a chemical unit, atoms form together to make molecules, which form the objects around you
Molecule
Made up of atoms, combine to form objects
Element
Substance consisting of atoms which all have the same number of protons
Compound
Two or more elements together
Ex: NaCl
Metals
On the left side and the middle
- luster
- malleable
- good conductors (electricity and heat)
- Usually solid (except mercury)
Matalloids
On the stair step
- can have both properties of metals and non metals
- can be shiny and brittle
- semiconductors ( allows some electricity to pass through put not all ex: computer chips)
Nonmetals
On the right
- dull
- brittle
- usually gasses
- good insulators (bad conductors)
