ChemistryChemistry

Chapter 4: What’s the Matter?Chapter 4: What’s the Matter?

Concept Attainment ActivityConcept Attainment Activity

States of MatterStates of Matter

There are three familiar There are three familiar statesstates ( (phasesphases) of ) of matter: matter: solidsolid: has a definite volume and shape : has a definite volume and shape (unless in small pieces, eg. sand)(unless in small pieces, eg. sand)liquidliquid: has a definite volume, but shape : has a definite volume, but shape depends on its containerdepends on its containergasgas: volume and shape are determined by : volume and shape are determined by surroundings surroundings

4.1 – Properties4.1 – PropertiesProperty: A characteristic used to identify Property: A characteristic used to identify a substance. Properties are observed!a substance. Properties are observed!

There are two types of properties:There are two types of properties:

1.1. Qualitative Properties are properties you Qualitative Properties are properties you can observe with the five sensescan observe with the five senses

2.2. Quantitative Properties are properties Quantitative Properties are properties that you can observe by taking a that you can observe by taking a measurement or simple testmeasurement or simple test

Describing Qualitative Properties:Describing Qualitative Properties:

PropertyProperty DescriptionDescription

ColourColour Is it black, white, colourless, greenish-Is it black, white, colourless, greenish-yellow…….?yellow…….?

TasteTaste Is it sweet, salty, bitter……?Is it sweet, salty, bitter……?

TextureTexture Is it fine, coarse, smooth, gritty….?Is it fine, coarse, smooth, gritty….?

OdourOdour Is it odourless, spicy, sharp, burnt….?Is it odourless, spicy, sharp, burnt….?

LustreLustre Is it shiny, dull….?Is it shiny, dull….?

ClarityClarity Is it clear, cloudy, opaque, Is it clear, cloudy, opaque, translucent…..?translucent…..?

Measuring Quantitative PropertiesMeasuring Quantitative Properties

PropertyProperty DescriptionDescription

TemperatureTemperature Temperature at which matter Temperature at which matter changes state. (changes state. (˚C ˚F, K)˚C ˚F, K)

MassMass The amount of matter in an object. The amount of matter in an object. (kg, g, mg, lb, oz, etc.)(kg, g, mg, lb, oz, etc.)

VolumeVolume The The amount of space that is occupied amount of space that is occupied by matter. (mL, L, cups, gal, tsp. etc.) by matter. (mL, L, cups, gal, tsp. etc.)

DensityDensity The mass per unit volume of a The mass per unit volume of a substance. (g/mL or kg/L)substance. (g/mL or kg/L)

1.1. Melting PointMelting PointTemperature at which a solid changes into a liquidTemperature at which a solid changes into a liquid

2.2. Freezing PointFreezing PointTemperature at which a liquid changes into a solidTemperature at which a liquid changes into a solid

Freezing and melting happen at the same temperature!Freezing and melting happen at the same temperature!

Example: water freezes at 0Example: water freezes at 0˚ but also melts at 0˚)˚ but also melts at 0˚)

3.3. Boiling PointBoiling PointTemperature at which a liquid changes into a gasTemperature at which a liquid changes into a gas

Melting points and boiling are properties Melting points and boiling are properties that can help identify a substance.that can help identify a substance.

Most substances have two temperatures at Most substances have two temperatures at which they change state:which they change state:

PlasmaPlasma A gas that has electricity running through it.A gas that has electricity running through it.

Sometimes called the 4Sometimes called the 4thth state of matter state of matter

Found in nebulas, stars and the northern Found in nebulas, stars and the northern lightslights

Found in TVs, Neon Lights and Found in TVs, Neon Lights and Fluorescent lightsFluorescent lights

Watch this Watch this video

4.3 Mass and Volume4.3 Mass and Volume

Everything in the Universe is made of Everything in the Universe is made of matter or Energymatter or Energy

Matter is made up of particles called Matter is made up of particles called atoms and molecules. atoms and molecules.

It is anything that has a mass and It is anything that has a mass and occupies space.occupies space.

MASS: a measurement of the amount of MASS: a measurement of the amount of matter in an object.matter in an object.

WEIGHT: the force of gravity pulling on an WEIGHT: the force of gravity pulling on an object. object.

Mass is the same everywhere in the Mass is the same everywhere in the universe but weight will change depending universe but weight will change depending on the force of gravity.on the force of gravity.http://www.exploratorium.edu/ronh/weight/

Metric UnitsMetric UnitsVery small masses are measured in Very small masses are measured in

milligrams (mg)milligrams (mg)– milli means 1/1000milli means 1/1000

Small masses in grams (g)Small masses in grams (g)Large masses in kilograms (kg)Large masses in kilograms (kg)

– kilo means 1000kilo means 1000

1 mg = 1/1000 g and 1 kg= 1000 g1 mg = 1/1000 g and 1 kg= 1000 g

How can we convert between mg, g, kg?How can we convert between mg, g, kg?

mg mg g: divide by 1000 g: divide by 1000(or move the decimal place 3 places to the left)(or move the decimal place 3 places to the left)

g g mg: multiply by 1000 mg: multiply by 1000(or move the decimal place 3 places to the right)(or move the decimal place 3 places to the right)

g g kg: divide by 1000 kg: divide by 1000(or move the decimal place 3 places to the left)(or move the decimal place 3 places to the left)

kg kg g: multiply by 1000 g: multiply by 1000(or move the decimal pace 3 places to the right)(or move the decimal pace 3 places to the right)

1.1. Direct Measurement: a measurement that Direct Measurement: a measurement that takes one step.takes one step.

• When you can put an object right on a scaleWhen you can put an object right on a scale

2.2. Indirect measurement: a measurement Indirect measurement: a measurement that takes multiple stepsthat takes multiple steps

• When you have to put the object in a When you have to put the object in a container on a scalecontainer on a scale

Measuring Mass – A Quantitative Measuring Mass – A Quantitative PropertyProperty

Measuring Mass – A Quantitative Measuring Mass – A Quantitative PropertyProperty

To find mass indirectly, you need to put the To find mass indirectly, you need to put the object in a container. object in a container.

Example: finding the mass of sand or water. Example: finding the mass of sand or water. Mass of water = 30 gMass of water = 30 g

(mass of container + substance) – ( mass of container)(mass of container + substance) – ( mass of container)

50 g – 20 g = 30g50 g – 20 g = 30g

Measuring Volume – A Measuring Volume – A Quantitative PropertyQuantitative Property

Volume: a measure of the amount of Volume: a measure of the amount of space that is occupied by matter.space that is occupied by matter.

Volume of a solid is Volume of a solid is usually give in cmusually give in cm33

Volume of a liquid in Volume of a liquid in mL or LmL or L

1 cm1 cm33 = 1 mL = 1 mL

and and

1000 cm1000 cm33 =1L =1L

cm3cm3

mL

Liters (L)

Metric UnitsMetric Units

How can we convert between mL, and L?How can we convert between mL, and L?

mL mL L: divide by 1000 L: divide by 1000(or move the decimal place 3 places to the left)(or move the decimal place 3 places to the left)

L L mL: multiply by 1000 mL: multiply by 1000(or move the decimal place 3 places to the right)(or move the decimal place 3 places to the right)

There are many different ways to measure There are many different ways to measure volume.volume.

1.1. Graduated CylinderGraduated Cylinder Used with liquidsUsed with liquids Always measure below the MeniscusAlways measure below the Meniscus Make sure that your eye is level with the Make sure that your eye is level with the

meniscus meniscus

Measuring Volume – A Measuring Volume – A Quantitative PropertyQuantitative Property

http://www.taw.org.uk/lic/itp/itps/measuringCylinder_1_2.swf

2.2. MathematicallyMathematically Volume of a Rectangular solidVolume of a Rectangular solid

Volume= length x height x widthVolume= length x height x width=4cm x 2cm x 3cm=4cm x 2cm x 3cm= 24 cm= 24 cm33

3.3. Displacement MethodDisplacement Method Irregular SolidsIrregular Solids

V of object= (V of water + object) – V of waterV of object= (V of water + object) – V of water

Ex) When a stone is dropped into a Ex) When a stone is dropped into a graduated cylinder filled with 10mL graduated cylinder filled with 10mL water, the water raises to 35mL. water, the water raises to 35mL. What is the volume of the object?What is the volume of the object?

35mL – 10 mL = 25mL 35mL – 10 mL = 25mL

http://www.taw.org.uk/lic/itp/itps/measuringCylinder_1_2.swfhttp://www.taw.org.uk/lic/itp/itps/measuringCylinder_1_2.swf

1.1. Direct Measurement: a measurement that Direct Measurement: a measurement that takes one step.takes one step.

• Using a graduated cylinder or mathematically Using a graduated cylinder or mathematically calculating volume are direct methods of calculating volume are direct methods of measurement.measurement.

2.2. Indirect measurement: a measurement Indirect measurement: a measurement that takes multiple stepsthat takes multiple steps

• The displacement method is an indirect The displacement method is an indirect method of measurement.method of measurement.

Measuring Volume – A Measuring Volume – A Quantitative PropertyQuantitative Property

Calculating Density 4.5Calculating Density 4.5

• Why does oil float on water?Why does oil float on water?• Because it is less dense than water!Because it is less dense than water!• What is density?What is density?

Density is the mass per unit volume of a Density is the mass per unit volume of a substancesubstance

Density is a quantitative propertyDensity is a quantitative property

Density can be calculated using a formula.Density can be calculated using a formula.

D= m/VD= m/VDensity is expressed in g/cmDensity is expressed in g/cm33 and g/mL and g/mL

Each substance has its own unique Each substance has its own unique density (see Table 1 page 109)density (see Table 1 page 109)

Water has a density of 1.00 g/mlWater has a density of 1.00 g/ml

A substance will float in water if is has a A substance will float in water if is has a density less than 1.00 g/mldensity less than 1.00 g/ml

A substance will sink in water if is has a A substance will sink in water if is has a density greater than 1.00 g/mldensity greater than 1.00 g/ml

If you mix crude oil and water, which will If you mix crude oil and water, which will sink and which will float? Why?sink and which will float? Why?

The density of crude oil is 0.86 – 0.88 g/mLThe density of crude oil is 0.86 – 0.88 g/mL

The density of water is The density of water is

1.00g/mL1.00g/mL

The oil will float because it is less dense The oil will float because it is less dense than water. than water.

Comparing DensitiesComparing Densities

Birch wood has a density of 0.66 g/cm3 (in other words 0.66 g/mL) which means that every cubic cm of birch wood has a mass of 0.66 g

Will birch float or sink in water? 

Birch will float when placed in water since its density (0.66 g/cm3) is less than that of water (1.00 g/mL)

Comparing DensitiesComparing Densities

Will a piece of iron sink or float in water? Will a piece of iron sink or float in water? The density of iron is 7.87 g/cmThe density of iron is 7.87 g/cm3 3 ??

Sink because its density is more than that Sink because its density is more than that of water (1.00 g/mL)of water (1.00 g/mL)

If water (D = 1.00 g/mL), rubbing alcohol If water (D = 1.00 g/mL), rubbing alcohol (D = 0.79 g/mL) and vegetable oil (D = (D = 0.79 g/mL) and vegetable oil (D = 0.92 g/mL) were all placed in a container, 0.92 g/mL) were all placed in a container, in what order would you expect to settle in what order would you expect to settle out? List them from top to bottom. out? List them from top to bottom.

Comparing DensitiesComparing Densities

The The rubbing alcohol rubbing alcohol would be the would be the toptop layer layer since it’s the least dense and would since it’s the least dense and would therefore float on top of the other therefore float on top of the other substances. The substances. The vegetable oil vegetable oil would form a would form a middlemiddle layer since it would sink below the layer since it would sink below the alcohol but float on the water. The alcohol but float on the water. The waterwater would form a would form a bottombottom layer since it has the layer since it has the highest density so would sink in the other highest density so would sink in the other substances.substances.

ExamplesExamples

Calculate the density of a substance with a Calculate the density of a substance with a mass of 340 g and a volume of 811 mLmass of 340 g and a volume of 811 mL

D= m/VD= m/V

= 340= 340gg / 811 / 811 mLmL = 0.42 = 0.42 gg/ / mLmL

Calculating DensityCalculating Density

A block of fir measures 240 cmA block of fir measures 240 cm33. If its mass is . If its mass is 144 g, find the density of the wood.144 g, find the density of the wood.

D = m / V D = m / V

D = 144 / 240 D = 144 / 240

D = D = 0.6 g/cm0.6 g/cm33