Chemistry Unit 1 Study Cards

for both standard and honors chemistry unit 1

density

mass ÷ volume

the amount per unit size

Law of Conservation of Mass

mass cannot be created or destroyed

Law of Conservation of Energy

energy cannot be created or destroyed

matter

anything that has mass and takes up space

Percentage of error

(error ÷ accepted value) ×100

difference between yours and actual values

chemistry

study of atoms and how they interact

physical property

properties determined without causing chemical change

chemical property

properties determined only through chemical change

chemical reaction

new substance is formed

quantitiative

observations involving #’s

observation

directly see and measure object/event

accuracy

how close to intended target

mass

quantity of matter in an object

physical changes

changea that don't change the chemical composition

chemical change

a new substance is formed

extensive property

depends on the amount

ex) heat

4 indicators of Chemical change

1) color change

2) production of gas

3) temperature change

4) production of odor

**5) formation of a precipitate

qualitative

observations expressed in words

inference

draw conclusions based on observations

precision

how close they are to each other

weight

force of gravity on object

atom

basic unit of matter

energy

the capacity for doing work

compouds

formed by 2+ elements which are chemically combined

properties very different from what makes it up

mixtures

substances formed when elements and/or compounds are physically mixed together

-heterogeneous= NO uniform composition throughout mix

-homogeneous= mixture has uniform comp. down to molecular level

metal characteristics

good conductors, malleable, ductile, shiny, reflective

non-metal characteristics

poor conductors, brittle if solid

metalloid characteristics

moderately good conductors, moderately brittle

solid

definite shape & volume

compact particles

liquid

not definite shape, flows

definite volume

space between particles

gas

no definite...

shape: takes shape of container

volume: fills its container

Lots of space between particles

scientific notation rules and how to do them

For Big Numbers (like 4,500,000)

1. Move the decimal to the left until there is only one non-zero digit in front of it.

   • Example: 4,500,000. becomes 4.5 [1, 2]

2. Count your jumps to see how many places you moved the decimal point.

   • Example: You moved it 6 places. [1, 2]

3. Write it down as your new number times 10 to that positive power:

   • 4.5 × 10⁶

For Small Numbers (like 0.00032)

1. Move the decimal to the right until it sits right after the first non-zero digit.

   • Example: 0.00032 becomes 3.2

2. Count your jumps to the right.

   • Example: You moved it 4 places.

3. Write it down with a negative exponent:

   • 3.2 × 10⁻⁴

sig fig rules

• Non-zero numbers are always significant (e.g., 123 has 3 sig figs).

• Zeros between non-zero numbers (trapped zeros) are always significant (e.g., 104 has 3 sig figs).

• Leading zeros (at the very front) are never significant (e.g., 0.004 has 1 sig fig).

• Trailing zeros (at the very end) are only significant if there is a decimal point. [1, 2]

sig figs how to find them

• Add or Subtract: Round your answer to the least number of decimal places.

  • Example: 12.1 + 3.42 = 15.52 -> round to tenths place = 15.5 [1]

• Multiply or Divide: Round your answer to the least total number of sig figs used in the problem.

  • Example: 5.0 (2 sig figs) × 1.23 (3 sig figs) = 6.15 -> round to 2 sig figs = 6.2