Chem test two

Flashcards covering basic definitions, measurement concepts, and significant figure rules from the chemistry lecture.

Chemistry

The study of matter and its interactions and changes

Matter

anything that has mass and takes up space

Theory

Describes why/how something occurs; an explanation of the existing evidence

Law

Describes/predicts what happens (often mathematical)

Accuracy

getting the 'correct' or 'accepted' answer consistently

Precision

Getting constant, repeatable data

Observations

qualitative descriptions

Qualitative

Qualities. color, texture, formation of solids, liquids, gases

Quantitative

numerical data

International System (IS) of Measurment

the official units of science

SI units

units in the international system of measurement

Dimensional analysis

A method for converting units, using an “Equivalent expression” as a conversion factor

Significant digits

The numbers obtained by proper measurement (the digits known with certainty, plus one estimated digit).

Measurment

quantitative data; had a number and a unit.

All non-zero numbers

numbers are significant

Middle zeros

are always significant

Trainling zeros

are only significant if there is a decimal present

Leading zeros

are never significant

Organic chemistry

The study of Carbon based compounds

Inorganic chemistry

Compound that are not carbon based, but there can be some overlap

Pure chemistry

Done for the sake of pursuing new knowledge

Applied chemistry

When there is a specific goal or problem to solve

Unit

Standard quantity used for measurement, like kilogram or meter. Give measured numbers meaning in terms of scale and context

Mass

How much matter is present

Volume

The space matter occupies

Temperature

The average kinetic energy of particles

Temperature unit of measurement

Kelvin (K) or Celsius (C)

Absolute zero

-273 °C

Kelvin temp

°C + 273

Kelvin temperature is a scale for which

Negative values are not possible

0 °C

Water freezing/melting point, standard temperature

100 °C

Water boiling point

~20-25 °C

Room temperature

37°C

Human body temperature

Volume of a cube

Length x width x height

Density

A derived unit; It is made up of other units. Is the ratio of a substances mass per unit volume, usually in g/mL or g/cm³

When recording a calculated answer

You can only be as precise as your Least precise measurement

Addition and subtraction with sig digs

Answer has least number of decimal places as appears in the problem

Multiplication and division with sig digs

Answer Has least number of sig figs As appears In the problem

Scientific notation

A form of writing very large or very small numbers that you’ve probably used in science or math class before

The decimal point is put

Behind the first non-zero number

The power of 10 is the number of times

The decimal moved to get there

Scientific notations on calculator

2nd

,

the number

Why are units important?

The magnitude of a number is ambiguous without a unit

Equivalent can be expressed as a fraction, called a

Conversion factor

Dimensional analysis equivalents

An expression of two equal quantities in different units

Conversion factor

Equivalent that are expressed as a fraction

Dimensional analysis is not cross multiplication

True