Elements, Compounds and Molecules
Subscripts and Coefficients
Physical and Chemical Changes
Chemical Equations
Balancing Equations
100
the name for two or more DIFFERENT atoms bonded together.
compound
100
What is the large number written before the element's symbol?
Coefficient
100
What is a change that results in the formation of a new substance and cannot be reversed?
Chemical Change
100
The substances you start with in a chemical equation
reactants
100
How do you balance equations?
adding coefficients
200
the combination of two or more substances
mixture
200
What do subscripts indicate?
how many atoms of that element you have bonded together in a molecule
200
(unexpected) color change, Gas production, Light production, Temperature change, Precipitate are evidences of what type of change?
Chemical
200
the substances created in a chemical change/equation
products
200
what can never be changed while balancing equations
subscripts
300
how many atoms, total in the following 6H2O?
18
300
How many total atoms are represented in
2Fe2O3
10
300
Milk rotting is an example of a what type of change?
Chemical
300
How many atoms, total, in the following equation
5 Na(SO4)2
55
300
___ Rb + ___ S8 --> ___ Rb2S
Balance this Equation
_16__ Rb + ___ S8 --> _8__ Rb2S
400
What is a pure substance that is represented by every box on the periodic table?
Element
400
What are small numbers written after an element's symbol?
subscript
400
What are changes that do not change the composition of a substance, but may alter the appearance?
Physical Change
400
What is this called in a chemical equation?
yield sign
400
This states that the number and kinds of atoms on the reactants has to be the same as the number and kinds of atoms on the products side.
Law of Conservation of Mass
500
how many different kinds of atoms are in one element?
1
500
What do coefficients indicate?
Indicate the number of molecules you have present
500
Changes in size / shape
Melting / boiling
Breaking / cracking
Mixing things
are evidences of what type of change?
Physcial
500
___ Na + ___ Cl2 --> ___ NaCl
What are the reactants in this image?
Na and Cl2
500
Why is this equation not correct
_32__ Rb + _2__ S8 --> _16__ Rb2S
its not simplified.