1. Test Review PowerPoint for 4th Period

2. Reactants and Products
Reactants are combined together
to create products
What are the reactants and products in the following equations?
C + 2O CO H + O H2O
Reactants
Product
Products
Reactant
What do you notice about these equations?
Coefficients-big numbers (in front)
Subscripts-small numbers (behind)

3. Chemical Equations
Label the reactants and products on the chemical equation below:
CaCO3 CaO + CO2
Reactants
Products

4. Label the reactants and products. On the practice worksheet.
Mg + O2 MgO
2H2O2 2 H2O + O2
2Cu2O + C 4Cu + CO2
FeS + 2HCl FeCl2 + H2S
P4O10 + 6H2O 4H3PO4
Fe2O3 + C Fe + CO2
SO2 + O2 SO3

5. Conservation of Mass
You must end up with the same amount you started with.
Mass cannot be created or destroyed

6. Conservation of Mass
Matter is not created or destroyed

7. Balancing Equations
Goal- Have the same number of atoms on both sides of the equation.
Rules
Coefficients (numbers in front) multiply
You can not change subscripts (numbers behind)
If there is no subscript after an atom, then you know there is only 1 atom present

8. Balancing Equations
1. Write equation
2. Count Atoms
H O
H O 2 2 2 1

9. Balancing Equations 3. Use coefficients to balance the equation 4 2
H O 2
H O 2 2 2 4 1 2
3. Use coefficients to balance the equation

10. H O
H O 4

11. Balancing Equations Practice2 2
H O2  H2O
H Cl2  HCl
SO2 + O2  SO3
Mg + O2  MgO 2 2 2 2 2

12. How do we make the reaction go faster?
There are four things that we can change to make the reaction go faster.
They are
Temperature
Surface area
Concentration
Using a catalyst

13. 1. Temperature
When we increase the temperature we give the particles energy
This makes them move faster
This means they collide with other particles more often
So the reaction goes faster.

14. 2. Surface area
If we make the pieces of the reactants smaller we increase the number of particles on the surface which can react.
This makes the reaction faster.
The particles on the surface can react
When cut into smaller pieces the particles on the inside can react

15. 3. Concentration If we make one reactant more concentrated,
there are more particles in the same volume to react
So the reaction goes faster.
There are less red particles in the same volume so there is less chance of a collision
There are more red particles in the same volume so there is more chance of a collision so the reaction goes faster

16. 4. Using a catalyst
A catalyst is a chemical which is added to a reaction.
It makes the reaction go faster.
The catalyst does not get used up in the reaction.
It gives the reaction the energy to get started

17. Enzyme catalyst

18. Elements Made of atoms of one kind
The type of element depends on the atomic number, or the number of protons it has
Most elements occur naturally, but some have to be created in a lab

19. Periodic Table
Elements are organized on the Periodic Table according to atomic number and properties of the element
Open textbook to pages L14 – L15

21. Symbol
The abbreviation letters used for each element

22. Atomic Number
Number of protons (each element has a different # of protons)
Number of electrons (same as # of protons so the element is electrically neutral)

23. Atomic Mass atomic mass ( rounded) – atomic number
Mass of the Atom or # of the protons plus neutrons
Each proton equals 1 amu and each neutron equals 1 amu (atomic mass unit)
How do you find the average number of neutrons in an atom?
atomic mass ( rounded) – atomic number

24. Groups Groups: or Family = columns
Share similar properties
Numbers on top indicate what group it is
Noble gases-Group 18 (or 8A)
Halogens-Group 17 (or 7A)
Alkali metals-Group 1

25. Periods Periods = rows Atomic mass increases from left to right
Number of protons increases from left to right
Number of electrons in the outer shell of the atom increases from left to right
Only hydrogen and helium are in the 1st period

26. Look at L14 –15 or L186 – L187

27. Physical Properties description
Physical properties can be observed or measured without changing the identity of the matter.
They are determined by the use of the
They are a of an object.
Five senses
description

28. Examples of Physical Properties
Color
Smell
Taste
Hardness
State of Matter (solid, liquid or gas)
Boiling, Freezing, or Melting Point

29. Examples of Physical Properties
Density
Mass
Volume
Conductivity - The ability of a substance to allow the flow of energy or electricity.

31. Physical vs. Chemical
Physical properties: observe without changing the identity of the substance
Chemical properties: observe only when the identity changes
How do you know if it is chemical or physical?
If it CHanges, it’s CHemical
Combustion of Mg strip

32. Chemical Properties react Are determined by a substance’s ability to
_______with other substances.
react

33. Chemical properties Reactive to oxygen Reactive to air
A common chemical property is reactivity.
Reactive to oxygen
Reactive to air
Reactive to water…
Reactive to acid
Notice that chemical properties aren’t EASY to observe, unlike physical properties.

34. Examples of Chemical Properties
air
The ability to react with
, _______, _________, __________
The ability to catch fire ( )
rust
tarnish
corrode
rot
Water or acids
flammability

36. Physical or Chemical Property?
1. Ability of gun powder and fire to explode.
Chemical Property

37. Physical or Chemical Property?
2. The color of a sunset.
Physical Property

38. Physical or Chemical Property?
3. The ability of a nail to rust.
Chemical Property

39. Physical or Chemical Property?
4. The shape of a leaf.
Physical Property

40. Physical or Chemical Property?
5. The ability of wood to burn.
Chemical Property

41. Physical or Chemical Property?
6. The hardness of a diamond.
Physical Property

42. Physical or Chemical Property?
7. The volume of your soda.
Physical Property

43. Physical or Chemical Property?
8. The mass of two camels.
Physical Property
Complete Physical and Chemical Properties worksheet
in your packet – page 5

44. Atoms Modern Atom Model Nucleus-Protons and Neutrons
Electrons around nucleus, never know the true location

45. Protons
Positively charged particle
In nucleus
Mass 1 amu

46. Neutrons
Neutral (no) charge particle
In nucleus
Mass 1 amu

47. Electrons Negatively charged particle
In electron cloud (orbitals) around the nucleus
Mass 0 amu

48. Chemical Changes
A change in matter that results in one or more new substances. You change what it is. Chemical in the original substance combines with another chemical to create a new substance

49. Evidence of Chemical Reactions or Change
(2:52) Evidence of a Chemical Reactions

50. Evidence of Chemical Change
New ________appears
Bubbbles or ________
Precipitate forms (____ material)
color
_____ is produced
______ is produced
______ is given off
Heat
fizzing
Light
Sound
solid
Difficult or impossible to __________
reverse