Unit 2: Chemistry Flashcards
Physical Change
A change that can be reversed and still has the same particles where no new substance is formed
Example: cutting paper, freezing H2O, melting butter
Chemical Change
A Chemical change is a change in which a whole new substance is formed. For example, when you are baking cookies the baking soda when heated gas is released making the new substance fluffier and lighter. A chemical change cannot be reversed.
Example: sodium and water
Qualitative
Properties that can only be described by words.
Example: colour, texture, and state of matter.
Quantitative
Properties that can be defined by a precise measurement ( A numerical value)
Example: boiling point, mass, density.
Homogenous mixture
can’t see different particles usually clear cannot be filtered to separate particles
Example: Windex
Heterogeneous or mechanical mixture
not uniformly scattered you can see different particles
Example: cookies muffins
Pure substances
only one type of particle
Example: sugar
Element
more than 100 substances that cannot by ordinary chemical means be separated into different substances
Proton
positively charged particle
found inside the atomic nucleus
Neutron
uncharged particles in the
atomic nucleus
Matter
anything that takes up space and can be weighed
example: volleyball
Molecule
Smallest independent unit of pure substances. Generally, a cluster of atoms joined together
Example: Tightly joined together molecules is an atom
Solution
A homogeneous mixture of 2 or more pure substances
Example: Brass made from copper and zinc
Suspension vs Colloid
Suspension is when 2 heterogeneous mixtures mix in which particles settle
A colloid is between a solution and a fine suspension
Scientific Law
Law is used to summarize an observation
Fore = Mass x Ecelleration
Scientific theory
Theories are possible reasons why something acts the way it does
Example: Atom theory is matter is made up of tiny particles
Cation
If an atom loses electrons it becomes positively charged and is called a cation
Anion
if an atom gains electrons it becomes negatively charged and is called an anion
Example: K-
Metal
Usually a solid shiny, conductive material
Example: brass
Non-metal
An element or substance that is not metal; Liquid or gas
Example: helium
Metalloid
Elements with properties in between metals and nonmetals
Valence Electron
Electron that is on the outer shell of the atom. Controls the atom’s chemical properties.
Ionic bond
Electrons transferred between a non-metal and metal are then attracted to each other because of the negative and positive charges.
Covalent bonds
Electrons shared between 2 non-metals
Diatomic molecule
molecules that when bonded with another of themselves they are more stable
Compound
Pure substances That are made up of two or more elements bonded together
Multivalent Ions
ion with more than one # of positive or negative ions
Polyatomic ions
ions with more than one atom
Chemical formula
tells us three things about the compound
1 how many atoms
2 which elements are present
3 what state of matter it’s in
valence shell
outermost shell of an atom containing the valence electrons
Products
the substances produced by
a chemical reaction
Reactants
The substances that go into a chemical reaction
Exothermic
Chemical reaction where heat energy is released to the surroundings
Endothermic
Chemical reaction where heat energy is taken away from the surroundings
Formation
2 separate elements combine to form a compound or 2 simple compounds combine to form a complex compound
Decomposition
A compound separates into 2 elements or a complex compound separates into 2 simple compounds
Single replacement
there is one element and one compound then the element switches places with another element in the compound
Double replacement
there is 2 compounds and the two negatively charged ions switch places.
Combustion
the highly exothermic
combination of a substance with
oxygen; requires heat, oxygen,
and fuel
Catalyst
A substance that speeds up a chemical reaction, the substance isn’t used up. (eg: sodium solution in elephant toothpaste. )
Enzyme
A type of catalyst that speeds up biological processes. Eg: Aylase:
enzyme that is in saliva, breaks down carbohydrates.
