1. Energy and Matter
College Chemistry

2. Scientific Method Steps can be done in ANY order!
State the problem clearly.
Gather information.
Form a hypothesis
Test the hypothesis.
Evaluate the data to form a conclusion.
6. Share the results.

3. Scientific Method
Data that you observe can be qualitative or quantitative
Qual – observations
Quant – think “quantity”, numbers
Theory vs. law
Theory – principle that explains a set of facts, observations that describe something, explains what
Law – statement (usually mathematical) that explains how something works, explains why

4. Energy The capacity to do work or to produce heat
It does NOT have matter or volume – you cannot see it or touch it
Two types of energy – kinetic and potential
Kinetic energy – energy of motion
Potential energy – energy of an object at rest

5. Energy Measured in Joules 1 Joule = 1/1000 of a food-calorie
1 J of energy:
Required to lift an apple 1 meter
Kinetic energy of a tennis ball moving 14 mph
Energy released by a person sitting every 1/60 of a second

6. Law of Conservation of Energy
Energy cannot be created or destroyed
It can only transform from one form to another
Ex: kinetic to potential, heat to electrical

7. Matter Anything that has mass and volume (exists and take up space)
Solid – holds a particular shape and has a definite volume
Liquid – does not hold its own shape, but does occupy a definite volume
Gas – no definite shape or volume

8. Element
An element is a substance that CANNOT be broken done into any simpler substances by a chemical change
All on the periodic table
All have abbreviations – chemical symbols

10. Compound
A compound is two or more elements that have been combined chemically
Chemists generally use symbols for a compound using the elements they came from
Ex: magnesium oxide - MgO

11. Compounds and Elements
Compounds and elements are pure substances
Each element and compound has a unique set of chemical and physical properties

12. Molecules Simplest form of a compound
Can contain just one element (a compound must have at least 2 different elements!!)
Ex: N2 – molecule H2O - compound

13. Mixture A mixture is a blend of two or more pure substances
Physically combined, NOT chemically

14. Types of Mixtures
Mixtures may not appear to be of more than one type of matter (think of Kool-Aid)
Heterogeneous mixture – mixture that has visibly different parts (choc. Chip cookie, granite)
Homogeneous mixture – mixture that does NOT have visibly different parts
AKA: solution

15. Substance
Substance – form of matter that has a definite composition and distance properties (includes elements and compounds)

17. Physical vs. Chemical Changes
Physical – can be observed and measured without changing the composition or identity of a substance
Ex: melting ice
Chemical – changes the entire chemical compound
Ex: H2 + O2  H2O

18. Measurable Properties of Matter
Extensive –
Depends on how much matter is present
Ex: mass, volume
Intensive –
Does not depend on how much matter is present
Ex: density, temperature