The smallest part of all matter
Atom
When the number of each reactant’s atoms and the number of each product’s atoms are
equal, the chemical reaction is
balanced
Smallest part of a substance
Atom
In a chemical process, atoms that make up a substance are regrouped into different
_____________________ to form new substances with different properties.
molecules
Materials made by humans
Synthetic materials
Fe+O2→Fe2O2
4Fe+3O2→2Fe2O3
When atoms of substances rearrange
themselves into a new configuration
Chemical reaction
The result of a chemical reaction
Product
The substance that is produced from a chemical
reaction
Product
A _____________________ increase or decrease and the production of light are both signs
that a chemical reaction may have occurred.
temperature
If a chemical reaction occurs, the properties of substances before and after the
substances interact must be ________________________.
different
N2+H2→NH3
N2+3H2→2NH3
To prevent the loss of something
Conserve
The ___________________ is the number placed in front of a chemical symbol in a
balanced equation
coefficient
Formed when two or more atoms chemically combine
Molecule
A _____________________ is a solid substance that forms and separates from a solution
and may indicate that a chemical reaction has occurred.
precipitate
_________________ and _________________ properties can be used to identify
pure substances
chemical, physical
KClO3→KCl+O2
2KClO3→2KCl+3O2
How much matter is in an object
Mass
The ___________________ is the number written below and to the right of a chemical
symbol to show how many atoms are present.
subscript
The substances initially involved in a chemical reaction
Reactants
An unexpected change in _____________________ is a sign that a chemical reaction may
have occurred.
color
Plastic is an example of a(n) ___________________ because it is made from
natural resources that have been chemically processed
synthetic material
C4H10+O2→CO2+H2O
2C4H10+13O2→8CO2+10H2O
The total number of atoms of each element
is not changed during a chemical reaction.
Law of conservation
of mass
The ______________________________________________ states that matter is not
created or _____________ in a chemical reaction. The total number of ____________ is
conserved, and the _____________ does not change.
law of conservation of mass, destroyed,atoms,mass
A process that leads to the transformation of one set of
chemical substances to another
Chemical reaction
Substances giving off a smell, or ________________, while being combined is also an
indicator of a chemical reaction.
odor
____________________ can be chemically processed to make synthetic materials.
natural resources
Mg+HCl→MgCl2+H2
Mg+2HCl→MgCl2+H2