Ch 1 Chem Test

scientific method

a procedure for processing and understanding information gathered during experimentation

qualitative

involves the qualities of the result of an experiment

quantitative

makes a measurement; needs a number and units

natural law

theory that has been tested and never proven incorrect

SI units of measurement for mass

kilogram (kg), gram (g)

SI units of measurement for length

meter (m)

SI units of measurement for time

seconds (s)

SI units of measurement for temperature

Kelvin (K), Celsius (°C)

conversion from Celsius to Kelvin

K = C + 273

SI units of measurement for amount of a substance

mole (mol)

what is the number used for moles in conversions

6.023 × 10²³

what is the difference between mass and weight

mass is the amount of space an object takes up and weight is the measure of gravity on an object

does mass change with gravity

no

does weight change with gravity

yes

conversion from mL to cm³

1 mL = 1 cm³

types of lab equipment that will measure volume

graduated cylinder, pipet, buret, volumetric flask

are beakers used to measure volume

no

meniscus

the curve all liquids have when in containers

where should you measure from when measuring liquid in a container

bottom of the meniscus

what is the difference between accuracy and precision

accuracy is how close a measurement is the the measurement its expected to be and precision is how reproducible a measurement is

density formula

d = m/v

Which state(s) of matter does not have definite volume

gas

Which state(s) of matter do not have definite shapes

liquid and gas

homogeneous

two or more substances in a mixture that are evenly distributed

heterogeneous

two or more substances in a mixture that has visibly distinguishable parts

distillation

uses boiling points of two different substances in a mixture to separate them

filtration

separates a solid and liquid in a mixture

compound

a substance that is made up of elements, but can still be broken down into smaller parts

element

substances that cannot be decomposed into simpler substances

what is the difference between a compound and mixture

a compound is chemically combined, a mixture is not

when measuring volume based on markings on equipment, how many decimal places are allowed to be guesses

1 place

random errors

error that has an equal probability of being high or low; usually occurs when reading uncertain digits in measurements

systemic error

same error each time; same repeated error

what is the difference between a random error and a systemic error

random errors have equal chances of being high or low and systemic errors are a result of making a mistake

what is the rule for sig figs when adding and subtracting

line up the decimals in the top and bottom, whichever column in the top has the least decimal places, that is the place that you round to in the bottom (the numbers in front of the decimal don't factor into sig figs)

what is the rule for sig figs when multiplying and dividing

the lowest amount of sig figs in the equation is the amount of sig figs you use in the equation

temperature

a measure of the average kinetic energy of (space in between) molecules

why do we use Kelvin in chemistry equation

in order to make sure answers in equations don't have negative answers

chemical change

a substance becomes a new substance with different properties and different compositions; a reaction occurs

physical change

a change in state of the substance occurs but the properties and compositions are still the same