Chemistry UNIT 1 TEST

Chemistry

study of matter, its properties, and the changes it undergoes (medicine, biochemistry, technology)

Matter

has mass and takes up space

2 classifications of matter

state and composition

composition of matter

pure substance and mixture

Pure substance

has distinct composition that doesn’t vary

two kinds of pure substances

elements and compounds

Element

can’t be broken down; one type of atom

Compound

can be broken down through chemical means; different elements in a fixed ratio that are chemically bonded

Mixtures

multiple types of elements or compounds and can be separated through physical means (homogenus and heterogenus)

Homogenous

uniform composition (can’t see different parts)

Heterogenous

not uniform composition (example: salad)

Physical change

substance doesn’t change, change of state (size,shape), dissolving something in water

Chemical change

substance does change, gas, light, or heat production, color change, smell production, creation of new substance

Accuracy

the closeness of measurements to the true value

Precision

the closeness of a set of measurements to eachother

percent error

can be calculated to compare an experimental value with the correct value

distilation

separates 2 liquids with different boiling points

filteration

separates an insoluable solid from a liquid

sig figs

digits that are actually measured ending with the last digit that was estimated

adding and substracting sig figs

round your final answer the least number of decimal places

multiplying and dividing sig figs

round your final answer to the least number of sig figs

Base units for dimensional analysis

grams, meters, liters

S.I units

KHDDCM