Ch 1 Properties of Matter.pptx

7/28/2019 Ch 1 Properties of Matter.pptx

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Chapter 1

Properties of Matter


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1. Phases of Matter

2. Density

3. Pressure in Fluids

4. Atmospheric Pressure and Gauge

Pressure

Units of Chapter 1


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General Properties of MatterMatter is anything thathas mass and volume

Everything is made ofmatter


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The three common phases of matter are solid,liquid, and gas.

Solid fixed shape, fixed size, tightly packed

and the particles vibrateLiquid Liquids have particles that are close

together, but are free to move. Takes the shape

of the container, its volume can be changed

significantly only by a very large forceGas neither fixed shape, nor a fixed volume.

1.1 Phases of Matter


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FLUID

Since liquid+gas do not

maintain a fixed shape, theyboth have the ability to flow

FLUIDS


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What are properties?Characteristics used todescribe an object

Ex: color, odor, shape,size, texture,hardness


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General Properties of matterMass, weight, volume,

and densityProperties are used to

identify a substance


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What is mass?

Mass is the amount ofmatter in an object

Mass is constant

Mass is also the

measure of inertia


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What would take up more space???

A kilogram of feathers..or a kilogram of steel??

OR


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Density is the measure of the

compactness of a material

More than just the heaviness of a

substance, density includes howmuch space an object takes up!!

All substances have density

including liquids, solids, and gases


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Compactness


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1.2 Density

Density is given by:

The symbol for density is rho.Density is simply mass per unit

volume.

)(

)(

Vvolume

mmass


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Substance Density (kg/m3)

Solid

Aluminium 2.70 103

Iron and steel 7.8 103

Copper 8.9 103

Lead 11.3 103

Gold 19.3 103

Concrete 2.3 103

Granite 2.7 103

Wood (typical) 0.3 0.9 103

Glass,

common

2.4 2.8 103

Ice 0.917 103

Bone 1.7 2.0 103

Substance Density (kg/m3)

Liquid

Water (4C) 1.00 103

Sea water 1.025 103

Blood, plasma 1.03 103

Blood, whole 1.05 103

Mercury 13.6 103

Alcohol, ethyl 0.79 103

Gasoline 0.68 103

Substance Density

(kg/m3)

Gas

Air 1.29

Helium 0.179

Carbon dioxide 1.98

Water (steam, 100C) 0.598


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1.2 Density

Example 1-1: Mass, given volume and

density.

What is the mass of a solid iron wrecking

ball of radius 18 cm?


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Liquid Layers

If you pour together liquids that dont mixand have different densities, they will form

liquid layers.

The liquid with the highest density will beon the bottom.

The liquid with the lowest density will be

on the top.


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Liquid Layers

Check out this picture. Whichlayer has the highest density?

Which layer has the lowest

density?

Imagine that the liquids have the

following densities:

10g/cm3. 3g/cm3.

6g/cm3. 5g/cm3.

Which number would go with

which layer?


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Liquid Layers Try on your own!

Imagine that the

liquids on the right

have the following

densities: 15g/cm3 10g/cm3

3g/cm3 9g/cm3

7g/cm3 12g/cm3

Match the colors tothe correct densities.

3g/cm3

7g/cm3

9g/cm3

10g/cm3

12g/cm3

15g/cm3


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1.3 Pressure in Fluids

(1) Variation of pressure with area:

Pressure is defined as force per unit

area.

Is a scalar quantity, with SI unit Nm-2 orPascal (Pa).

)()(

AareaFforceP


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Example 1.2: Calculating pressure.

The two feet of a 60-kg person cover an

area of 500 cm2.

(a) Determine the pressure exerted by thetwo feet on the ground.

(b) If the person stands on one foot, what

will the pressure be under that foot?

P D d D th t


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Pressure Depends on Depth, notShape

All these containers are the same height.

Therefore, the pressure at the bottom of each is

the same. The shape matters not!

Note: Were talking about the pressure inside the fluid, not

the pressures exerted by the containers on the table,

which would greater for a cylinder than a cone of the sameheight & base.


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1-3 Pressure in Fluids

Pressure is the same in everydirection in a static fluid at a

given depth; if it were not, the

fluid would flow.


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Pressure in Fluid

(2) Variation of pressure with depth

ghP This relation is valid for

any liquid whose

density does not

change with depth.


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At sea level the atmospheric pressure is about1.013 x 105 N/m2; this is called 1 atmosphere (atm).

Another unit of pressure is the bar:

1 bar = 1.00 x 105 N/m2.

Standard atmospheric pressure is just over 1 bar.

This pressure does not crush us, as our cellsmaintain an internal pressure that balances it.

1-4 Atmospheric Pressure and

Gauge Pressure


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Most pressure gauges measure the pressure

above the atmospheric pressurethis is called

the gauge pressure.

The absolute pressure is the sum of the

atmospheric pressure and the gauge pressure.

1-4 Atmospheric Pressure and

Gauge Pressure


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Atmospheric Pressure (Patm)

Absolute pressure at three different point

are:-

CatmC

BatmB

atmA

ghPP

ghPP

PP

A

B

C

hB hC


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Example 1.3

A 50 kg woman balances on one heel of

a pair of high heeled shoes. If the heel

is circular in shape and has a radius 0.5

cm, what pressure does she exerts on

the floor?

Parmg

AFP 10245.6

)105.0(81.950 6

222

V i ti f P i diff t


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Variation of Pressure in different

materials

A

B

Liquid A

Patm

C P3

P1

P2

Liquid B

Liquid C

hA

hC

hB

AAatm ghPP 1

BBghPP 12 CCghPP 23


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Example 1.4

a) Calculate the absolute pressure at an

ocean depth of 1000 m. Assume the

density of seawater is 1024 kg m-3 and

the air exerts a pressure of 101.3 kPa.

Pa10015.1

)100081.91024()103.101(

)(

7

3

P

P

ghPPa wateratm


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Example 1.5

Givenwater= 1103 kg m-3 and oil =

0.82103 kg m-3. Calculate the pressure

at the bottom of the tank.

Oil

B

Patm = 101.3 kPa

Water

P1

P2

1.4 m

2 m


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Pa10322.1

)2)(81.9)(101(10126.1

is,bottomat thepressuretheTherefore,

Pa10126.1)4.1)(81.9)(1082.0(103.101

5

2

352

12

5

1

33

1

1

P

P

ghPP

PP

ghPP

waterwater

oiloilatm


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Question 1

If you try to smuggle gold bricks by filling

your backpack, whose dimensions are

60 cm 25 cm 15 cm, what would itsmass be?

Givengold= 19.3 103 kg m-3


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kgkgm

m

cm

mcmmV

kgm

cmcmcmcmV

VmV

m

25.434103.190.0225mm

0225.0

1

)101(22500:in

103.19and

22500152560Given

333

3

3

33233

33

gold

3


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Question 2

Estimate the pressure exerted on a floor

by:

a) A pointed loudspeaker leg (60 kg onfour legs) of area = 0.05 cm2, and

compare it

b) to the pressure exerted by a 1500 kgelephant standing on one foot (area =

800 cm2)


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2-5

4

2-7

22

Nm1084.110800

81.91500

Nm1094.2

4)10(05.0

81.960

Pe

A

FP

P

A

F

P

e

ee

s

s

s

s


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Question 3

What is the pressure at the bottom of a

swimming pool of 22 m by 8.5 m whose

uniform depth is 2 m? What will be thetotal force on the bottom of the

swimming pool?

Patm = 1.013 105 Nm-2water= 1 10

3 kg m-3


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N103.2

)5.822()102.1(

Nm102.1

)2)(81.9)(101()10013.1(

7

5

2-5

35

F

APF

A

FP

P

P

PPP poolatm


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Density The density of water is 1.0 g/ml

Objects with densities greater

than 1.0 will sink in water

Objects with densities less than

1.0 g/ml will float on water


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Ice

Ice floats therefore it isless dense than water


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Astronomy fact!

The planet Saturn has a

density of less than 1.0 g/ml.

If there was an ocean big

enough to hold it, it wouldfloat!


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CalculationsIf 96.5 grams of goldhas a volume of 5 cubic

centimeters, what isthe density of gold?


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Calculation

If 96.5 g of aluminum has a

volume of 35 cm3, what is the

density of aluminum?


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Calculation

If the density of a diamond is 3.5

g/cm3, what would be the mass of

a diamond whose volume is 0.5

cm3?

S f Ch t 1


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Phases of matter: solid, liquid, gas

Liquids and gases are called fluids.

Density is mass per unit volume.

Pressure is force per unit area.

Pressure at a depth h is gh.

External pressure applied to a confined fluid is transmitted

throughout the fluid.

Gauge pressure is the total pressure minus theatmospheric pressure.

Summary of Chapter 1


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Ch 1 Properties of Matter.pptx