1. Properties and Changes Section 3.1
Properties of Matter
Properties and Changes
Section 3.1

2. What is Matter?
Matter =
Substance: matter that has a uniform and unchanging composition, aka pure substance
Mixture: two or more substances that have been combined and each substance retains its own chemical identity (sugar + flour)
Pure Substances Impure Substance (mixture)
distilled water ocean = water + salt

3. Physical Properties
Substance – matter that has a uniform and unchanging composition
Example: salt – NaCl
Physical properties – characteristics that can be observed or measured without changing the composition of the sample
viscosity hardness density
conductivity melting point color
malleability boiling point odor

4. 2 Types of Physical Properties
Extensive properties – dependent on the amount of substance present
Intensive properties – independent of the amount of substance present

5. Recognizing Physical Changes
Some of the properties of a material change, but the substances in the material remain the same; chemical composition remains the same; some are reversible
heating butter
crumpling paper
slicing a tomato
wrinkly shirt/iron
hair braiding
peeling oranges
Change of state
Ice-melting  liquid

6. Physical Separation of Substances
magnetic properties crystallization/evaporation
filtration chromatography
distillation manual separation

7. Phases of Matter
Materials can be classified as solids, liquids, gases, or plasma based on whether their shapes and volumes are definite or variable
Shape and volume are clues to how the particles within a material are arranged

8. Solids Definite shape and volume
Atoms are packed close together and have an orderly arrangement of particles
Changing the container doesn’t change the shape or volume of a solid
Examples: pencil, cafeteria tray, book, quarter

9. Liquids Definite volume and take the shape of its container
Can be poured, will take on a new shape
Atoms are close together, but their arrangement is more random than those of a solid
Examples: juice, water, mercury, honey

10. Gases Does not have a definite shape nor a definite volume
Takes the shape and volume of its container
Atoms are not arranged in a regular pattern and can have a big space between them
COMPRESSIBLE
Examples: Air, helium, natural gas

11. Plasma Ionized gas with enough energy to have free electrons lightning
sun
neon signs

13. Kinetic Energy of Phases of Matter
plasma
gas
liquid
solid

14. Very close together, orderly arrangement Fixed No
Particles
Shape
Volume
Compressible?
Solid
Very close together, orderly arrangement
Fixed No
Liquid
Close together but not as orderly as solid
Changes
Gas
Lots of space between, no order
Yes

15. Chemical Properties
Chemical properties – the ability of a substance to combine with or change into another substance
Iron + O2 -> Rust (FeO)
Burning
Cooking
CO2 + H2O -> C6H12O6 + O2
EVERY SUBSTANCE HAS A UNIQUE SET OF PHYSICAL AND CHEMICAL PROPERTIES

16. Chemical Equations
A useful description of a chemical reaction tells you the substances present before and after the reaction
Reactants undergo the change and the new substances that are formed are the products
Reactants Products

17. Recognizing Chemical Changes
Evidence of chemical changes include:
Change in color – leaves on trees, banana peel, copper, silver
Production of gas (bubbles) – vinegar and baking soda, cake baking
Formation of a precipitant – acid + milk (protein goes
through chemical change), cottage cheese
Production of light
Temperature Change – reaction causes heat to be
given off or absorbed (gets cold)
Endothermic
Exothermic

18. Law of Conservation of Mass
Mass is neither created nor destroyed
Mass reactants = Mass products
Reactants  Products
H2O + O2 H2O
18 grams + 22 grams  ? H2O

19. Steps to Solve Law of Conservation of Mass Problems
Write what you know
chemical reaction
reactants and their masses
products and their masses
What are you solving for?
Solve for your unknown

20. Practice!
From a laboratory experiment designed to separate water into hydrogen and oxygen gas, a student collected 10.0 g of hydrogen and 79.4 g of oxygen. How much water was initially involved in the process?
Chemical Reaction
H2O  H2 + O2
Reactants  Products
Law of Conservation of Mass says…
Mass reactants = Mass of Products
H2O mass = H2 mass + O2 mass
H2O mass = 10.0 g g
H2O mass = 89.4 g
What do we know?
H2 = 10.0 g
O2 = 79.4 g
What is our unknown?
H2O = ??? g

21. More Practice!
A student carefully placed 15.6 g of sodium in a reactor supplied with an excess quantity of chlorine gas. When the reaction was complete, the student obtained 39.7 g of sodium chloride. How many grams of chlorine gas reacted?
Chemical Reaction
Reactants  Products
Sodium + Chlorine  Sodium Chloride
Law of Conservation of Mass says…
Mass reactants = Mass of Products
Sodium mass + Chlorine mass = Sodium Chloride mass
15.6 grams + ? grams = 39.7 grams
? grams = 24.1 grams of Chlorine
What do we know?
Sodium = 15.6 g
Sodium Chloride = 39.7 g
What is our unknown?
Chlorine = ??? g

22. Practice! Law of Conservation of Mass says…
In a flask, 10.3 g of aluminum reacted with 100 g of liquid bromine to form aluminum bromide. After the reaction, no aluminum remained, and 8.5 grams of bromine remained unreacted. How many grams of compound were formed?
Law of Conservation of Mass says…
Mass reactants = Mass of Products
Aluminum used+ Bromine used = Aluminum Bromide made
10.3 grams grams = ??? grams
grams = ? Grams of Aluminum Bromide
Chemical Reaction
Reactants  Products
Aluminum + Bromine  Aluminum Bromide
What do we know?
Aluminum = 10.3 g
Bromine = 100 g
Bromine left over = 8.5 g
Bromine used = ??
= 100 – 8.5 g
= 91.5 g
What is our unknown?
Aluminum Bromide = ??? g

23. Practice!
A 10.0 g sample of magnesium reacts with oxygen to form 16.6 g of magnesium oxide. How many grams of oxygen reacted?
If 50 grams of sodium reacts with chlorine to form 126 grams of salt, how many grams of chlorine reacted?
If 20 grams of aluminum reacts with 200 grams of bromide to form aluminum bromide, and no aluminum is left after the reaction, but 23 grams of bromine remained unreacted how many grams of aluminum bromide were formed?

24. Practice!
If g of water is separated into hydrogen and oxygen gas, and the hydrogen gas has a mass of 20.0 g what is the mass of the oxygen gas produced?
From a laboratory process, a student collects 28.0 g of hydrogen and g of oxygen. How much water was originally involved in the process?

25. Practice!
9. A student carefully placed 23.0 g of sodium in a reactor with an excess quantity of chlorine gas. When the reaction is complete, the student obtained 58 grams of salt. How many grams of chlorine reacted? 10. A 10 gram sample of iron reacts with oxygen to form 18.2 grams of ferric oxide. How many grams of oxygen reacted?