The Study of Chemistry

Page 1

Matter and Energy

Gas = changes shape, changes volume

Solid = fixed shape, fixed volume

Liquid = changes shape, fixed volume

Plasma = ionized gas (electrons are free to move)

Examples of Thermal Energy:

mechanical energy

radiant energy, or light (electromagnetic) energy

electrical energy

sound energy

chemical energy

Physical Change = change to a substance that does not alter its chemical composition

Chemical Change = change that results in the formation of one or more new substances

Exothermic = characterized by a net release of energy

Endothermic = characterized by a net absorption of energy

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1.07 Laboratory: Paper Chromatography

What do good safety practices look like in a Science Lab?

Follow all instructions given (do not do any unapproved experiments or fool around) and report any injuries, accidents or damaged glassware

Dress appropriately: Tie back long hair (chin-length or longer), wear long pants, secure any loose clothing, and use shoes that cover the toes

Do not taste chemicals (no eating or drinking of anything in the lab) or smell chemicals directly. (When required, waft the smell by waving it toward you)

Learn where the safety equipment is kept (fire extinguisher, eyewash station, first aid kit, and safety shower) and how to use it

Never point a test tube being heated toward you or another person

Leave your lab station neat and clean after you are finished

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1.09 Properties of Substances

Mass- How much matter does a particular substance contain?

Volume- How much space does the substance take up?

Shape- Is it round or square? Flat or fluffy?

Density- What is the ratio of mass to volume?

State- Is it solid, liquid, or gas?

Color or Luster- What color is it? How shiny is it?

Hardness- How easily does it scratch other substances?

Viscosity- How easily does the liquid flow?

Odor- What does it smell like?

Magnetism- Does it attract certain metals?

Solubility- How well does the substance dissolve in another substance?

Freezing Point- At what point does it become solid or melt?

Boiling Point- At what point does it boil or condense?

Properties of a Chemical Change:

- Color change

-Gas is given off

-Energy is given off (Temperature might increase, an explosion might occur, or sound, heat or light may be released

-Energy is absorbed (Temperature may decrease)

-A precipitate may form

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1.13 Metric System: Base Units

1 centimeter (cm) = 1/100 of a meter or 0.01m

1 millimeter (mm) = 1/1000 of a meter or 0.001m

1 micrometer (Mm) = 10^-6

1 decimeter (dm) = 1/10 of a meter or 0.1m

1 kilometer (km) = 1,000 meters (m)

1 kilogram (km) = 1,000 grams (g)

1 milligram (mg) = 1/1,000 of a gram or 0.001 g

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1.14 Metric System: Derived Units

meter (m) = length

kilogram (kg) = mass

kelvin (K) = temperature

second (s) = time

mole (mol) = amount of a substance

candela (cd) = light intensity

ampere (A) = electrical current

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1.15 Graphing

Independent Variable = in an experiment, the variable that the experimenter changes

Dependent Variable = in an experiment, the variable that the experimenter observes as a result of changing the independent variable