The document discusses the differences between pure substances like elements and compounds, and mixtures like heterogeneous mixtures which are not uniform throughout and homogeneous mixtures which are uniform. It also covers separation techniques like distillation and filtration that can be used to separate mixtures based on differences in their physical properties like boiling point or ability to be filtered. Key concepts around chemical properties and evidence of chemical changes are also reviewed.

1. CHEMISTRY|
CHAPTER 2
Lexi Ringsby

2. What is matter?
Matter is everything, and can be either a pure substance, or a mixture.
Matter
Pure Substances Mixture
Element Compound Homogenous Heterogenous

3. Pure Substances
Can only be broken down chemically
In a fixed ratio
Unique set of properties, independent of amount
Can be either a compound or element
Compound ex: H2O
H2O is a compound because it is made up of two or more elements, represented by
capital letters, and because its smallest particle is a molecule
Element ex: Au (gold)
Au is an element because its smallest particle is an atom, and has only one capital

4. Mixtures
Unlike pure substances, mixtures are not in any fixed ratio
Does not have a unique set of properties
Can be separated physically
ex: salt and pepper
Salt and pepper is an example of a mixture because it is not in a fixed ratio, can be
separated by physical means, and does not have unique properties.

5. Heterogeneous Mixtures
A heterogeneous mixture is a mixture that is not uniform throughout, and is made
up of substances that remain physically separate.
ex: sand
Sand is heterogeneous because it has visibly different substances in it, that vary in
size, as well as properties

6. Homogeneous Mixtures
Homogenous mixtures are uniform throughout
Have particles that are the same size
ex: salt water

7. Suspensions, Colloids, and
Solutions
A suspension, a heterogeneous mixture, is layered
ex: oil and water
A colloid=homogenous and has larger particles that make it impossible to see
through
ex: homogenized milk
Solutions: a homogenous mixture with smaller particles that make it possible to see
through
ex: gatorade

8. Physical Properties
Density, conductivity, hardness, viscosity, boiling point, melting point, and
malleability are all physical properties
Physical properties can be used to either to determine if the substance is pure, to
separate mixtures, or to simply determine what a substance is.

9. SEPARATION
TECHNIQUES

10. Distillation
Distillation involves separating mixtures based on boiling point data.
Equipment used: A distillation apparatus.

11. Filtration
Filtration involves using some sort of filter paper to separate a mixture. Left in the
paper remains the residue, while inside the test tube is the filtrate
Equipment: Test tube, filter paper, original mixture, and funnel.

12. Examples
Filtration Example: Separation of sulfur and sodium chloride both substances
are mixed with water, the sulfur is filtered out. Then, salty water is placed in
evaporating dish and water is evaporated using evaporation.
Distillation Example: Unknown liquid lab.

13. CHEMICAL
PROPERTIES

14. Evidence of a Chemical Change
1. Change of color
ex: oxidization of copper makes it turn green
2. Production of a gas
ex: water electrolysis demo
3. Formation of a precipitate
ex: cottage cheese

15. Chemical Properties
Flammability: materials that burn can be used as fuel. When something is burned,
it can never be brought back. Therefore, it is a chemical property.
Reactivity: the property that describes how readily a substance combines
chemically with other substances. When a substance reacts, it cannot be brought
back, again proving that it is a chemical property.

16. Electrolysis Demo

17. REVIEW QUESTIONS

18. Blue food coloring is added to
water. Is this a physical change or a
chemical change?

19. Answer: That is a physical
change, because the original
water could be obtained by
using distillation.

20. Fill in this chart.

21. What is an alloy?

22. Answer: An alloy is a
mixture of metal.
Follow up question: Is gold an alloy?
No. It is a pure substance.

23. Answer

24. What are the physical
properties we know of ?

25. Answer: Hardness, density,
malleability, odor, melting
point, boiling point,
viscosity, conductivity, and
solubility.