chapter 15 forms of matter pages 450-465. chemical changes how to know if a chemical change took...
TRANSCRIPT
Chapter 15
Forms of matter
Pages 450-465
Chemical Changes
How to know if a chemical change took place?
New substances are formed. Energy is given off
Matter can be
Pure Substance -elements or
compounds -hard to break apart -well defined
composition
Mixture -easy to separate into
the components through common physical properties
Composition variable
Element vs. Compound
Elements – one type of atom.
Compounds – two or more atoms chemically combined.
More about mixtures……..
Heterogeneous Homogeneous
More mixture terminology
Solutions
Colloids
Suspensions
Properties of matter
Physical properties – Describe what
something looks like. color Metal? Conductor? Magnetic? State?
Chemical Properties – Describe how matter will act
Flammable Reactive Corrosive Toxic
T/F
All metals are magnetic All metals are conductors
Underline chemical and circle the physical properties.. Methane is a colorless,
odorless gas at room temperature, It is less dense than air and is highly flammable.
Chemical and Physical Changes
Physical Changes Any change in density,
color, shape.. No new substances are
made.
Chemical Changes New substances are
formed. Often energy changes
occur
samples
Cork Rubber Wood Zinc Copper Aluminum Tin Iron plastic
What physical properties do all metals share????? http://www.webelements.com/
ATB
Was the demonstrations a physical or chemical change? Why?
ATB
How would this be classified?
Mr. Frink obtained a beaker of a clear, odorless liquid. Upon further investigation he determined it to be an inflammable substance, to test this he ignited it. It burned vigorously producing carbon dioxide and water in the process.
Lab – Separating mixtures
Purpose: To separate mixtures into their components.
Hypothesis: Will we be able to use physical properties to separate mixtures????
Materials and Methods Day 1: chromotography
Test tube, mixture, chromatography paper Day 2: magnetism, filtration, evaporation
Mixture, magnet, googles, apron, filter paper, funnel, tin tray, stand, plastic tray
Observations
Day 1: Chromatography Day 2/3 Magnetism, filtration, boiling
Conclusion
1. Explain why we started with mixtures in both labs.
2. What properties did we use to separate the mixtures?
Vocab Card List
Substance Element Compound Heterogeneous Homgeneous Colloid Tyndall effect Suspension Fog
Physical property Chemical property Physical change Chemical change Distillation L.O.C.O.M. mixture
Methods 1 tray of mixture Run magnet through it Add 20 ml of water Filter it Let the water evaporate
Lab – Heat conductivity of metals
Purpose: The purpose is to measure how fast various metals conduct heat energy.
Materials and Methods Goggles, Bunsen Burner, timer, wax,
conductivity tester,
Data….
Table of metal vs. time to melt Bar graph of metal vs. time to melt
Conclusion
Is this lab a measurement of physical or chemical properties? Explain why.
How does thermal conductivity relate to The Kinetic Theory of Matter?
Mixtures
Two or more substances that are easily separated by physical means into their components.
Two categories of mixtures..
Heterogeneous- Components are easily
distinguished suspensions
Homogenous- Components are
blended evenly
Types of mixtures
Solutions Colloids suspensions
ATB- A paragraph in your notebook
Based on the results of the chromatography lab, was the food coloring an element, compound or mixture? Why
Lab – Separating a mixture.
Purpose: The purpose is to separate a mixture into its’ components using physical properties.
Hypothesis: How many components will compose the mixture?
Materials and Methods Goggles and apron Magnet Mixture sample Funnel and filter paper Tin tray Spatula stand
Methods Step 1: separate using magnetism Step 2: filtration Step 3: evaporation
Observations What were the components of the mixture,
describe how we separated them.
Conclusion Was this a heterogeneous or homogenous
mixture? Explain why. What physical properties did we use to
separate the mixture?
LOCOM
The law of conservation of mass In a “normal” chemical reaction no mass is
created or destroyed. This is a reaction that is not "normal"
LOCOM Lab
Purpose: The purpose is to prove LOCOM by burning steel wool.
Hypothesis: Will we violate the “law”. Materials and Methods Data:
Mass before =____________g Mass after =___________g
Group Before mass After mass
Conclusion
Why did the steel wool gain mass?
Did we violate the “law”?
What is the equation for what happened?
What were the chemical and physical changes you saw during the experiment?
Test review – chapter 15
Pure substances Element
Na, Cl H O
Compounds NaCl H2O
Mixtures Heterogeneous
Uneven, Colloids suspensions
Homogeneous Evenly blended solutions
Separating mixtures
Use physical properties Magnetism Boiling point (distallation) Filtration
Properties of Matter
Physical Properties State, color, density,
appearance, texture
Chemical Properties Reactivity,
flammability, corrosive toxic
Physical Changes Nothing new made
Chemical Changes New substances
made, energy is produced or absorbed
LOCOM
Mass is conserved H2 + O2 - H2O