Chemistry Chapter 2 Study Guide: Sections 1,2

Scientific method

logical approach to solving problems

Observing

the use of sense to obtain information

Qualitative

description

Quantitative

numerical

System

A specific portion of matter in a given region of space that has been selected for study during an experiment or observation

Hypothesis

testable statement

Hypothesis statements are often drafted as “______”

if-then

Controls

experimental conditions that remain constant

Variables

any condition that changes

Stages in the Scientific Method

Observing, Formulating Hypotheses, Testing, Theorizing, Publish Results

Model

A physical representation to explain something smaller or bigger

Theory

A broad generalization that explains a body of facts or phenomena

Quantity

Something that has magnitude, size, or amount

Length

meter

Mass

kilogram

Time

second

Temperature

kelvin

mega

10^6 | M

kilo

10³ | k

hecto

10² | h

deka

10^1 | da

deci

10^-1 | d

centi

10^-2 | c

milli

10^-3 | m

micro

10^-6 | µ

nano

10^-9 | n

Weight

measure of the gravitational pull on matter

To find density use:

D = m/v

To find mass use:

m = Dv

To find volume use:

v = m/D

cm³

mL

dm³

L

m³

kL

Directly Proportional

When one variable goes up, the other variable goes up.

Inversely Proportional

When one variable goes up, the other goes down.

Pacific-Atlantic Rule

If there is no decimal point, start from right to left. If there is a decimal point, start from left to right,

Addition/Subtraction w/ Significant Figures

Round to the least precise decimal point

Multiplication/Division w/ Significant Figures

Round to the least number of significant figures

Scientific Notation

M ×10^n

65,000 in scientific notation is

6.5 ×10^4

The percentage error equation is…

a measurement of accuracy

When using scientific notation,

only the significant numbers are shown

Natural Law

Describes how nature behaves, but does not explain why nature behaves the way it does.