Chem Notes Scientific Measurement The Study of Chemistry

Chem Notes 1.2 Classification of Matter Objectives: 1. I can classify matter into types of pure substances and mixtures 2. I can determine whether changes of matter are physical or chemical changes.

Why do we study chemistry? To understand what happens in the world around us…. There are many common observations that require chemistry to occur – Color – Energy (changes in) – Movement – Cars running – Function of your body – Growing food – Anything else?

Physical States of Matter There are three common states of matter: – Gas, Liquid and Solid State of MatterVolumeShape Gas Liquid Solid

Changes in Matter There are two types of changes in matter: – 1. Physical changes are changes when the identity of the substance does NOT change. For example boiling water (just the state changes – not the substance). – 2. Chemical changes are changes where the identity of the substance DOES change. This is a chemical reaction with reactants and products.

Four Evidences of chemical change Color change Formation of solid (precipitation) Formation of gas Changes in energy (heat)

Physical Properties and Chemical Properties… Physical Properties (related to physical change) – Something that can change without changing the identity of the substance Chemical Properties (related to Chemical change) – Something that can only be identified when changing the identity of the substance.

Key words Chemical change – Burn, oxidize, rust, erode, rot, decompose, digest, ferment Physical change – Cut, break, grind, melt, evaporate, boil

Chem Notes 1.3 Pure Substances and Mixtures Everything in our world is made up of atoms (at least for this year)! When we discuss atoms we can classify all matter into two general groupings: PURE SUBSTANCES and MIXTURES. Of course, these topics can also be further divided.

PURE SUBSTANCES: A substance that only consists of ___one substance____________ There are three types of pure substances. 1. Elements: Contain ONLY one type of atom (as listed on periodic table). Can either be monatomic or diatomic. 2. Allotropes: Multiple forms of the same element. Ex: carbon (graphite, diamond) 3. Compounds: Contain more than one atom and have a chemical formula. Ex: H 2 O

MIXTURES: A substance that contains _two or more substances______ There are two types of mixtures – 1. Homogeneous Mixture: Is mixed evenly throughout. Ex: 14-karat gold, sweet tea. – 2. Heterogeneous Mixture: Unevenly mixed. Ex: Chocolate chip cookie, salad…

Classify each of the following as Pure substances, Homogeneous or Heterogeneous Mixtures: 1. Gasoline5. copper 2. Stream6. wine 3. Air7. Oxygen 4. Brass8. salt

Often in Chemistry class we have to separate a mixture to identify the substance we are interested in. Fill in the following chart to determine the BEST method of separation based on the reactants you are using:

Separation ApparatusType of Separation (Physical or Chemical) Description of Technique What types of Matter will it separate? TWEEZERS SIFTING

Separation ApparatusType of Separation (Physical or Chemical) Description of Technique What types of Matter will it separate? MAGNET FILTRATION

Separation ApparatusType of Separation (Physical or Chemical) Description of Technique What types of Matter will it separate? EVAPORATION DISTILLATION

Separation ApparatusType of Separation (Physical or Chemical) Description of Technique What types of Matter will it separate? CHROMATOGRAPHY

1 I know the SI base units and prefixes and their symbols 2. I can convert numbers into and out of scientific notation. 3. I can do mathematical calculations in scientific notation. 4. I can use conversion factors to convert between units. ChemNotes 1.4: SI Units and Dimensional Analysis

In the SI unit system there are a specific set of units we use for each variable: Mass - ___________________ Time - ___________________ Volume - _________________ Pressure - ________________ Length - _________________ Amount - _______________ In science class there is a specific system of measurement that we use called the System International (SI units) – often referred to as the Metric System.

If we want a smaller or larger amount we use a system of PREFIXES. See the chart at the end of this packet. This allows us to CONVERT using conversion factors A SKILL YOU WILL REQUIRE in this class all year long. Let’s do some practice problems – where I will show you the steps:

EXAMPLE 1: How many milligrams are there in 0.25 grams? STEP ONE: Write down what you KNOW ! STEP TWO: Set up a conversion factor – Always make sure the unit you started with is in the denominator. Use your prefix chart to find the correct numbers. STEP THREE: If necessary set up a second conversion factor. STEP FOUR: SOLVE!

EXAMPLE 2: How many liters are there in 153 kiloliters? STEP ONE: Write down what you KNOW ! STEP TWO: Set up a conversion factor – Always make sure the unit you started with is in the denominator. Use your prefix chart to find the correct numbers. STEP THREE: If necessary set up a second conversion factor. STEP FOUR: SOLVE!

EXAMPLE 3: How many decimeters are in 26 meters? STEP ONE: Write down what you KNOW ! STEP TWO: Set up a conversion factor – Always make sure the unit you started with is in the denominator. Use your prefix chart to find the correct numbers. STEP THREE: If necessary set up a second conversion factor. STEP FOUR: SOLVE!

EXAMPLE 4: How many milliliters in 288 kiloliters? STEP ONE: Write down what you KNOW ! STEP TWO: Set up a conversion factor – Always make sure the unit you started with is in the denominator. Use your prefix chart to find the correct numbers. STEP THREE: If necessary set up a second conversion factor. STEP FOUR: SOLVE!

EXAMPLE 5: How many Megameters in 2004 decimeters? STEP ONE: Write down what you KNOW ! STEP TWO: Set up a conversion factor – Always make sure the unit you started with is in the denominator. Use your prefix chart to find the correct numbers. STEP THREE: If necessary set up a second conversion factor. STEP FOUR: SOLVE!