What is chemistry?
study of the composition (what a substance is), properties (ex.how colors are being absorbed), and transformations (reactions) of matter
What are the four parts of the Scientific Method?
Describe each step.
- Question/ Experiment: What's going to happen when....
- Observations: both taken before and after
- Hypothesis: came up with idea "if i do this... then this..."
- - refined hypothesis after experiment to come up with theory
- Theory: evolves from a hypothesis when it is proven correct/ proven over and over
How does a theory differ from a law?
- In general, a alwa is something that, over a long period of time, is tested and the outcome stays the same
- They do change, but rarely (only when their proven incorrect (sun revolves around earth= incorrect))
What is matter?
- anything that has both mass and volume
- ex. you can touch it, taste it, smell it
What is matter's counterpart?
- it doesnt contain matter (light, heat, chemical)
What is the composition of matter?
Composition comes from the elements
What is an element?
a pure substance with its own set of chemical and physical properties. Unless in nuclear chemistry, it can't be decomposed to smaller and simpler substances.
How did the periodic table come to be? Arrangement?
- arranged in different ways based on different things: masses of the elements, physical and chemical properties
- - things in columns, or families (groups) have similar physical and chemical properties (vertical column)= periodic trends
- - going across, they are called periods, or rows. They have similiarities, but not necessarily in terms of chemical
What are periodic trends:
things in the same column that do a certain type of thing
Properties of elements?
- physical properties: what a substance is
- chemical properties: what a substance does
Explain physical properties:
- characteristics that do not involve a change in a sample's chemical makeup
- intensive: does not depend on amount of substance present
- extensive: does depend on amount of substance present
Explain chemical properties:
- what a substance is
- characteristics that do involve a change in a sample's chemical makeup
What is the relationship between physical and chemical properties?
- a change in a physical property DOES NOT CHANGE the chemical composition of the substance
- a change in a chemical property DOES CHANGE the physical property of the substance
- EXCEPTION: something doesn't react with something else
True or False:
Not reacting can be a chemical property.
What are examples of physical properties? (12)
- melting point
- boiling point
- solid, liquid, gas
- specific heat