Unit 2 Matter & Change Notes

Is this a chemical or physical reaction? How do you know? ATMQ4http:// ATMQ4

Terms to Know A.Chemistry- The study of matter and the changes matter undergoes.

Terms to Know B. Mass- a measure of the amount of matter. C. Matter –anything that takes up space and has mass.

Terms to Know Three phases of matter: solid – has definite shape and definite volume liquid – no definite shape; definite volume gas – no definite shape nor definite volume

Wait a minute! I have heard of a 4 th state matter- Plasma Plasmas are a lot like gases, but the atoms are different because they are made up of free electrons and ions of the element.

Terms to Know D. Atom– smallest particle of an element that retains the chemical properties of the element E. Element- a pure substance made of only one kind of atom -from the Periodic table

Terms to Know F. Compound- composed of 2 or more elements in a fixed ratio –properties differ from those of individual elements EX: table salt (NaCl)

II. Properties and Changes in Matter A.Physical Properties of Matter characteristics which allow us to recognize and distinguish it from another substance Without changing the substance!!! –Examples of physical properties are color, odor, density, melting and boiling points and its physical state (solid, liquid, gas)

Physical Properties Malleable : Ability to be hammered into thin sheets Ductile: Ability to be drawn into a wire Luster: Ability to reflect the light

A. Properties and Changes in Matter Intensive property – does NOT depend on amount of substance present; is constant, examples are density, melting or freezing points, heat capacity, solubility Extensive property – depends on amount of matter present. Ex: mass, volume

** Intensive properties are so intense that the amount of matter doesn’t matter!!***

II. Properties and Changes in Matter B. Physical Changes of matter– does not alter the chemical composition of a substance. Physical changes usually are phase changes (going from solid to liquid) changes in size (cutting, grinding, etc), or dissolving in water.

II. Properties and Changes in Matter Know these 6 phase changes: –Melting: Solid to liquid –Evaporation/Boiling: liquid to gas –Condensation: gas to liquid –Freezing: liquid to solid –Sublimation: solid to gas –Deposition: gas to solid

Any change in state is a physical change…

A physical change is usually REVERSIBLE!!!

States of Matter xYFAj50c7xM

II.Properties and Changes in Matter C. Chemical Properties – the manner in which a substance reacts with another substance – we can only observe a chemical property when it undergoes a chemical change. Ex: Reactivity, flammability, heat of combustion, ability to oxidize

Write this down! H 2 + O 2  H 2 O Reactants Products

D. Chemical Changes of Matter Involves changing one substance into a new substance: cannot get the original substance back: burning, fermentation, cooking a steak, etc. A chemical change is a chemical reaction.

II. Properties and Changes in Matter 1. Reactants: starting substances/before arrow 2.Products: ending substances/after arrow Mg + 2 HCl  MgCl 2 + H 2 Reactants products

5 Signs of a Chemical Reaction There are five indicators that a chemical reaction has taken place. They are… 1.Color change 2.Temp. change 3.Gas. 4.Appearance of a precipitate (solid) 5.Light.

Demo time! What are some of the signs that you see from the demos that indicate a CHEMICAL REACTION?

Law of Conservation of Mass Law of conservation of Mass: The total mass of the reactants equals the total mass of the products. Matter is never created or destroyed.

Problem 1 Reactant A and reactant B are combined to form Product C. If there are 3 grams of reactant A and 5 grams of reactant B, how many grams of reactant C are formed?

Intensive or Extensive? 1.Boiling point Answer: Intensive 2. Melting point Answer: Intensive 3. Color Answer: Intensive 4. Odor Answer: Intensive 5. Mass Answer: Extensive

Physical or Chemical properties? 1.rusting iron Answer: Chemical 2. dissolving in water Answer: Physical 3. burning a log Answer: Chemical 4. melting ice Answer: Physical 5. grinding spices Answer: Physical

Learning Check 3 9 mL of oxygen gas were added to 18 mL of hydrogen gas to form water vapor. How many mL of water vapor were formed?

Activity Time!!!! Card Sorts – Making a T chart

Physical/ Chemical Changes Physical Changes Does NOT produce a new substance Is reversible Chemical Changes Produces a new substance Is NOT REVERSIBLE

Physical/Chemical Properties Physical Properties Does NOT require altering the material Does NOT require a chemical change Chemical Properties Requires altering the material Requires a chemical change

Intensive/Extensive Properties Intensive Properties Does NOT depend on the amount of matter Extensive Properties Does depend on the amount of matter