Unit 1Intro to Chemistry and

Measurement

Intro to Chemistry and PhysicsMr. Patel

SWHS

Topic Outline

• Learn Major Elements and Symbols• Intro to Chemistry (1.1, 1.2)• Significant Figures (3.1)• Measurement (3.1, 3.2)• Factor-Label Method of Conversions (3.3)

Intro to Chemistry

• Matter – anything that has mass and occupies space

• Chemistry – study of the composition of matter and the changes it undergoes

Intro to Chemistry

• Chemistry affects all aspects of life and other natural events!– Food Digestion– Leaves changing colors– Muscle contraction– Driving cars

Intro to Chemistry

• Five different areas or branches of chemistry

Organic Chemistry

• Study of all chemicals containing carbon

Inorganic Chemistry

• Study of chemicals that do not contain carbon

Biochemistry

• Study of processes that occur in living things

Analytical Chemistry

• Study that focuses on the composition of matter

Physical Chemistry

• Area that deals with the rate, mechanism, and energy transfer of chemistry

Types of Research

• Pure Chemistry – increase chemical knowledge

• Applied Chemistry – goal oriented

History of Chemistry

• Alchemy - change other metals to gold

• Lavoisier – Father of Modern Chemistry– Observation to measurement

Scientific Method

Significant Figures

• Sometimes we estimate numbers– If we measure between 9.8 and 9.9, we may say it

is 9.85.– We know that the 9 and 8 are definite; 5 is

estimated.• Discuss accuracy/precision later• Significant Figures – the digits from a

measurement that are known precisely plus an estimated digit

Measurement

• Measurement – quantity with a number and unit

• Accuracy – how close you are to the true value

• Precision – how close your measurements are to one another

Scientific Notation

• Used for very large or very small numbers• Converts a single number to a product of two

numbers– Ex: 8000 8 x 103

– Ex: 0.234 2.34 x 10-1

Scientific Notation Practice

1. 2522. 1250003. 0.003054. 0.00000000548

1. 2.52 x 102

2. 1.25 x 105

3. 3.05 x 10-3

4. 5.48 x 10-9

International System of Units (SI)

• Five SI base units: – meter (length)– kilogram (mass)– Kelvin (temperature)– Second (time)– Mole (amount)

Metric Conversions

Kilo - k 103 1000

BASE 100 1

Deci - d 10-1 0.1

Centi - c 10-2 0.01

Milli - m 10-3 0.001

Factor-Label Method

• Write down starting and ending unit• Write all relevant conversion factors• Cancel units to get to end unit– To cancel a unit, the unit must be on the top and

bottom

Conversion Examples

Presenting Data

• Data – numbers obtained or observations made during the experiment

• Organize data so that it is easier to read• Organize data with graphs and tables

Data Tables

• Simplest way to organize data

• Purpose: to show pure data.

• Table has a Title, category titles, and units.

Bar Graph

• Purpose: compare a set of measurements

Circle Graph

• Purpose: to show parts out of a whole

• Circle Graph has a title, axis labels, and bars that show data

Line Graphs

• These lines are very important: slope• slope = Rise/Run

• Proportional graphs• Inverse graphs• Always has Title, Axis Labels with units, any

relationships.

Variables

• Independent Variable – what is being changed by the researcher– Always along the x-axis of a graph (horizontal)– Time is usually always independent variable– This will cause something to happen

Variables

• Dependent Variable – the factor that is changing because of what the researcher changed– Always along the y-axis on a graph (vertical)– This is the response to the independent variable

Correlation

• Line Graphs can show a positive or negative correlation.

• This is correlation NOT causation – We can not say one thing causes another– One thing may lead to another