1 Matter and Change

2 What is Matter?  Matter is anything that takes up space and has mass.  Mass is the amount of matter in an object.

3 Properties  Used to identify a substance  Extensive Properties- changes when the amount of matter in a sample changes. Examples are mass, volume, length.  Intensive Properties- does not change when the amount of sample changes. Examples are density, pressure, temperature, color

4 Properties  Words that describe matter (adjectives)  Physical Properties- a property that can be observed and measured without changing the substance. (malleable, ductile, luster, phase changes)  Chemical Properties- a property that can only be observed by changing the type of substance. (burning)

5  Physical change- original substance exists Physical Change

6 Chemical Change  Chemical change- a new substance is produced (reactants lose identity) reactants reactants products

7 Indications of a chemical reaction  Energy absorbed (endothermic) or released (exothermic)  Color change  Release of gas  Precipitate-solid that separates from solution (insoluble, (s) subscript in products) Temperature of surroundings goes down Temperature of surroundings goes up

8 Types of Matter  Substance- an element or a compound Element- simplest kind of matter that cannot be broken down into simpler substances by chemical means. (All one kind of atom) Element- simplest kind of matter that cannot be broken down into simpler substances by chemical means. (All one kind of atom) Can be any element! B, Mg, Ar, Li, S

9 Types of Matter  Element- can be monatomic or diatomic  Mono- single (Li, Mn, He)  Di- two (Br 2, I 2, N 2, Cl 2, H 2, O 2, F 2 )

10 Diatomic Elements H2H2 N2N2 O2O2 F2F2 Cl 2 Br 2 I2I2

11 Types of Matter Elements can be allotropes Elements can be allotropes Definition: different forms of the same Definition: different forms of the same element element O 2 is oxygen O 3 is ozone Each contain only the element oxygen, but have different properties

12 Pure Substances  Compounds are composed of two or more elements chemically combined NaCl

13 Pure Substances  Compounds can be broken down by chemical methods  When they are broken down, the pieces have completely different properties than the compound. Na Cl 2 NaCl

14 Mixtures  Made up of two or more substances.  Variable composition.  Heterogeneous- mixture is not the same from place to place.  Mixed nuts, Chocolate chip cookie, Salad

15 Mixtures  Homogeneous- uniform composition (1 phase)  Kool-aid (solutions), air (gases), compounds  Every part keeps its properties

16 Solutions  Physically blended together  Can occur between any state of matter.  Solid in liquid- Kool-aid  Liquid in liquid- antifreeze  Gas in gas- air  Solid in solid - brass  Liquid in gas- water vapor

17 Compound or Mixture CompoundMixture More than one kind - Compound, Molecule or atoms Made by being chemically bonded or by a chemical change Made through a physical change or physically blended Homogeneous composition Variable composition Two or more different Atoms

18 Compound vs Mixture

19 Atom, Element, Compound, or Mixture

20 Which is it? Element Compound Mixture

21 Matter

22 Separating Mixtures  Only a physical change- no new matter is formed  Chromatography- separate homogeneous mixtures using a solvent

23 Separating Mixtures  Filtration- separates heterogeneous mixtures of solids and liquids

24 Separating Mixtures  Distillation- separates homogeneous mixtures due to different boiling points

25 Separating Mixtures Solutions  Can be separated by physical means  Not easily separated- can be separated without creating anything new. NaCl (aq) If you heat the solution, the water evaporates and the salt is left behind