Nat Sci Chapter 2 Notes

8/8/2019 Nat Sci Chapter 2 Notes

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Chapter #2Matter


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Notes 2.1

Chemistry: is the branch ofscience that

studies composition ofmatter and how it

changes. Matter: is anything that has mass and

occupies space. Examples air, water,

you

Light, sound, and electricity are not matter.

They have no mass or volume.


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Element: is a substance that cannot be

broken down into simpler substances.

Atom: is the smallest particle that has the

properties ofan element.

1 square

on the

periodic

table

2 or more

squares on the

periodic table


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Compound: is asubstance made ofatoms ofmore thanone elementchemically boundtogether.

Molecule: is thesmallest unit ofasubstance thatexhibits all the

propertiescharacteristic of thatsubstance.


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Chemical Formula is used to show how

many atoms ofeach element are present. Subscripts little numbers. Represent # of

atoms

ExamplesCH4

C6H12O6

C16

H10N

2

O2

H2O


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A pure substance is any matter that has a

fixed composition and definite properties. A mixture is a combination ofmore thanone pure substance. They are physicallymixed.


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Miscible describes two

or more liquids that areable to dissolve into

each other in various

proportions.

Immiscible describes

twoor more liquids that

do not mix into each

other.


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A heterogeneous mixture

is a combination of

substances that are not

uniformly mixed. Ex..

Italian Dressing

In a homogeneousmixture the substances

are uniformly mixed

through

out thecompound. Ex.. Salt

water


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Hetero


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3 States ofmatter

Solid particles have a rigid structure and a

definite shape and volume Liquid particles are fluids the particles can

slide past one another. No definite shape but adefinite volume

Gas particles are fluid. No definite shape orvolume.


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Viscosity- the resistance of liquid toflow

The thickerit is the higherthe viscosity.


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Evaporate- changing from a liquid to a gas.

Condenses- changing from a gas to a liquid.

Melting- changing from a solid to a liquid.

Freezing- changing from a liquid to a solid

Sublimation- changing from a solid to a gas


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Evaporation


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The lawofconservation ofmass- Mass

cannot be created or destroyed.

The lawofconservation ofenergy- Energy

cannot be created or destroyed.


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Chapter 2.3 Notes

Chemical Properties the way a substance

reacts toform new substance with

different properties

1. Reactivity the ability to combine

chemically with another substance

2. Flammability is the ability ofa

substance to burn when reacting with

oxygen and being exposed to a flame


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Physical property a characteristic ofa

substance that can be observed or

measured without changing the

composition of the substance

1. Melting point the temperature in which

a substance turn from a solid to a liquid

2. Boiling point the temperature at which

a substance turn from a liquid to a gas


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Density the mass per unit volume ofa

substance Density equation

D=m/V

Density=mass/volume Buoyancy-the force with which a more

dense fluid pushes a less dense

substance upward


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Chemical change- a change that occurs

when a substance changes composition by

forming

one

or m

ore ne

wsubstances

Odor, fire, light, rusting


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Physical change- a change in the physical

form or properties ofa substance that

occurs without a change in composition

Changes in state from solid

to liquid to gas are physical

changes it is still the same

substance


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Nat Sci Chapter 2 Notes

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