1. Matter and Change Test II
Unit 2
Matter and Change
Test II

2. Obj. 11-13…Separation of Matter
Elements are the purest substances on earth…they cannot be broken down any further.
Compounds are formed by chemically bonding two or more elements together.
~ must be chemically separated (reactions).
Mixtures are formed by physically combining two or more pure substances together.
~ can be physically separated.
Mixtures are separated by their physical properties.
~ boiling point, density, solubility etc…

3. Obj. 11-13 cont… How could you separate a mixture of sand and salt?
~ dissolve salt in water and filter out the sand.
** separation based on solubility!
How could you separate a mix of iodine and iron filings?
~ use a magnet to pull out the iron filings.
** separation based on magnetism!

4. Obj. 11-13 cont… Four methods of separation of mixtures… Distillation…
Ex…mixture of alcohol (BP = 78.5°C) and water (BP = 100°C)
separates a mixture of liquids based on different boiling points.

5. Obj. 11-13 cont… Filtration…
Ex…a sand and salt mixture
separates two solids based on their solubility (ability to dissolve) in different solvents.

6. Obj. 11-13 cont… Centrifugation…
separates substances based on the density of the particles in the mixture.
Ex…blood components, proteins in milk, precipitate in a liquid

7. Obj. 11-13 cont… Chromatography…
Ex… pigments in ink, pigments in chlorophyll
separates based on the absorption of the substances in the mixture.

8. Obj. 14…Physical vs. Chemical Properties
Physical properties…can be observed w/out changing the substance.
Ex…
~ color
~ density
~ texture
~ size
~ boiling/melting point
~ solubility
~ magnetism

9. Obj. 14 cont… Chemical properties…properties that explain how a
substance will react or behave.
Ex…
~ reactivity to…
 water
 acids
 bases
~ flammability
~ ability to be oxidized (lose e-)

10. Obj. 15…Physical vs. Chemical Changes
Physical changes…changes in appearance only…NOT
chemical make-up.
Evidence of physical changes...
~ color change (if same substance)
~ change in shape
~ change in temp. (manually heating and cooling)
~ change in size
~ change in phase

11. Obj. 15 cont… Examples of physical changes... ~ breaking a window
~ tearing / cutting a piece of paper
~ melting a piece of ice

12. Obj. 15 cont… Chemical changes…changes result in a re-arrangement or
recombination of atoms
(NEW substance!).
~ can’t get original substance back w/out chem. rxn.
Evidence of chemical changes...
~ gas / bubbles given off
~ formation of precipitate
~ heat given off / absorbed (breaking/making chem. bonds)
~ light given off
~ color change (if new substance)

13. Obj. 15 cont… Examples of chemical changes... ~ silver tarnishing
~ a nail rusting
~ burning a match
~ food rotting/souring
~ baking bread

14. Obj. 16…Law of Conservation of Mass
‘matter cannot be created or destroyed’
total mass on reactant side MUST = mass on product side.
~ ‘what goes into the rxn. must come out!’
Ex…
A B C D
5 grams
8 grams
2 grams
_________
11 grams
13 grams

15. Obj. 17-18…Density Density…amount of matter present in a given volume.
~ how heavy a substance is
D = m/v
units = g/ml or g/cm3

16. Obj. 17-18 cont… Density problems…
1. A nail has a vol. of cm3 and a mass of grams.
What is the density of the nail?
D = m/v
D = g / cm3
D = 7.86 g/cm3
2. Vegetable oil has a density of g/ml. Calculate the
mass of ml of oil.
m = D(v)
m = g/ml (500.0 ml)
m = 458 grams
3. The density of a piece of wood is 0.86 g/cm3. What is the
volume of the wood if its mass is 75 grams?
v = m/D
v = 75 g ÷ 0.86 g/cm3
v = 87 cm3

17. Obj. 17-18 cont… To calculate density of an object…
~ find mass of object using balance
~ find vol. of object by using the water displacement
method
** water displacement will not work if solid dissolves or floats in water.