CIS Chemistry Unit 1

Chemistry: Study of matter and the changes that it undergoes

Matter: ANything that has mass and volume

Mass: The amount of matter present

Volume: The amount of space an object takes up

Weight: Measure the gravitational pull on an object

5 Branches Of Study

  • Organic

    • The Study of subatances containing carbon

  • Inorganic

    • The study of substances not containing carbon

  • Analytical

    • Study of the composition of matter

  • Physical

    • The study of the behavior and changes of matter

  • Biochemistry

    • The study of matter and the process of living organisms

Scientific Method: A systematic approach to solving problems

Observations: “OOP I got a problem”

Hypothesis: Solve the problem

Experiments: Collecting, Analyzing, and writing data

Theory: Some sort of answer

“LAW”

Acts of gathering data

Qualitative: Measurement using descriptive words

Quantitative: Measurement using numbers

Educated Guess: If_____ Then____Because____

Controlled Observations that test the hypothesis

Independent Variables: Changed by the scientists

Dependent Variables: Changes due to the independent variable

Theory: Explanation of a natural phenomenon on many observations and investigations over time

Law: relationship in nature that is supported by many experiments

  • Pure Substances: Material thawt cannot be seperated by physical means

    • Atoms- Cannot be broken down

    • Compounds- Two or more chemicals bonded together

  • Mixture: Two or more pure substances mixed together

    • Eash substance retains its identity

  • Homogenous Mixture: Mixture that is blended smoothly

    • Pop

    • Steel

  • Hetergenous Mixture

    • Blood

    • Milk

    • Chicken Noodle Soup

Properties of matter

Property: Charicteristics of a substance

  • Physical Properties: A characteristic that can be measured or observed without changing the chemical composition

  • Chemical Properties: Characteristics that can be measured or observed only by changing the chemical composition

  • Extensive Property: Property that depends on the amount of matter present

    • Mass

    • Volume

  • Intensive property: Property that doesnt depend on the amount of matter present

    • Density

  • Physical Change: A change in a substance that does not change its chemical composition

    • Melting/Freezing

    • Dissolving

    • Bending

  • Chemical Change: Change in substance that changes its chemical composition (Cant get the substance back)

    • Rust

    • Digesting Food

    • Burning Wood

Measurements

2 different systems

english system

SI international system

Scientific Models: A physical mathematical or conceptual repersentation of a system of ideas events of processes

  • Diagrams: Takes something complex and make it easier to understand

  • Physical Repersentations

  • Computer Simulations

  • Mathematical Repersentations: Graphs and equations help us predict what might happen in future

  • Analogies: Useful relatable repersentation

Pros:

Uses real data

Simplifyies complex concepts

easier to understand

predictive abilities

can change the model

Cons:

Sometimes focused on one variable

doesnt show all aspects of phenomena

Wrong because they arent reality

Assumptions made

Significant Figuires: Digits in a measurement considered to be known

(except the last digit which is estimated)

  • Rule One: All Non-zero numbers in a measurement are significant

  • Rule Two: Zero between Non-zeros are always significant

  • Rule Three: All trailing zeros (after a number) are significant only if the number contains a decimal point

  • Rule Four: All zeros infront of the first non-zero number are not significant (Change the Unit)

  • Rule Five: Counting numbers and defined constants have infinite significance

  • Rule Six: Scientific notation ALWAYS expresses the correct number of significant figuires

  • Addition and Subtraction Rule: The final answer must be rounded to have the same number of places as the measurement with the least number of places

  • Multiplication and Division Rule: The final answer must be rounded to the number of significant figuires as the measurement with the least number of significant figuires

Density: The amount of matter in a given amount of space

Characteristic PropertyL defining preoperty that is unique to a substance

D=M/V

Mole: The SI base unit used to measure the number of particles of a substance

1mole= 6.022×10²³