Introduction to chemistry, measurement, and matter

Chemistry

study of composition, structure, properties, and reactions of matter.study of composition, structure, properties, and reactions of matter.

Composition

What is it made of?

Structure

How is it put together?

Properties

What characteristics does it have?

Reactions

How does it behave with other substances?

Matter

is anything that has mass and occupies space

Chemical

a substances that always has the same composition and properties wherever it is found.

scientific method

a set of general principles that helps to describe how a Scientist thinks.

observations

Make _______________ about nature and ask questions about what you observe.

hypothesis,

Propose a ____________ which states a possible explanation of the observations.

experiments

Several __________may be done to test the hypothesis.

conclusion

When results of the experiments are analyzed, a ________- is made as to whether the hypothesis is true or false.

metric system

Scientists use the __________ of measurement and have adopted a modification of the metric system called the International System of Units as a worldwide standard.

International System of Units (SI)

an official system of measurement used throughout the world for units of length, volume, mass, temperature, and time.

Measurement	Metric	S I
Length	meter (m)	meter (m)
Volume	liter (L)	cubic meter (m3)
Mass	gram (g)	kilogram (k g)
Temperature	degree Celsius (ºC)	kelvin (K)
Time	second (s)	second (s)

Exact number

The number of baseballs is counted, which means 2 is an ________

• doesn’t have Significant Figures

Measured number

a number you obtain when you measure a quantity such as length, mass, temperature, etc.

• has Significant Figures

Significant figures

deal with writing numbers to reflect precision.

the final answer is written to have the same number of significant figures (S Fs) as the measurement having the fewest S Fs.

Rule for Multiplication and Division with Measured Numbers

the final answer is written so that it has the same number of decimal places as the measurement having the fewest decimal places.

Rule for Addition and Subtraction with Measured Numbers

Deshawn has been diagnosed with diminished thyroid function. His doctor prescribes a dosage of "0.150 mg" of Synthroid to be taken once a day. If tablets in stock contain "75 mcg" of Synthroid, how many tablets are required to provide the prescribed medication?

Density formula

osteoporosis

a condition of severe thinning of bone

Pure substance

matter that consists of just one type of atom or one type of molecule.

Mixtures

contain two or more different substances that are physically mixed but not chemically combined

Characteristic	Solid	Liquid	Gas
Shape	Has a definite shape	Takes the shape of the container	Takes the shape of the container
Volume	Has a definite volume	Has a definite volume	Fills the volume of the container
Arrangement of Particles	Fixed, very close	Random, close	Random, far apart
Interaction between Particles	Very strong	Strong	Essentially none
Movement of Particles	Very slow	Moderate	Very fast
Examples	Ice, salt, iron	Water, oil, vinegar	Water vapor, helium, air

PHYSICAL PROPERTIES

are characteristics observed or measured without changing the identity of a substance.  Some common ones are: colour, state, density, melting and boiling point, etc.

PHYSICAL CHANGE

involves the conversion of a substance from one state of matter to another, without changing its chemical composition (no change in chemical formula).

Example: Freezing of liquid water into solid ice

CHEMICAL PROPERTIES

are properties of a substance describing a chemical change. Some common ones are: reactivity, flammability, corrosiveness, etc.

CHEMICAL CHANGE (Chemical Reaction)

happens when a substance changes into one or more new substances (chemical formula changes)

oExample: Reaction of sodium and water to produce NaOH and hydrogen gas

Energy

•is defined as the ability to do work

•can be classified as either kinetic or potential _____

Kinetic energy

is the energy of motion

(•When the water is released and flows over the dam, its potential energy is converted to kinetic energy.)

Potential energy

is determined by the position of an object or its chemical composition

(•Water in a reservoir behind a dam has potential energy.)

Joule (J)

The SI unit of energy and work is the ______

•The ____ is a small amount of energy, so scientists often use the kilo____ (kJ), 1000 ____


same ans for all*

calorie

The unit ______ is defined as the amount of energy needed to raise the temperature of 1 g of water by 1 ºC.


1 ______= 4.184 Joule