Chapter 15 Forms of matter Pages 450-465. Chemical Changes How to know if a chemical change took...

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