U1 Test Review Vocab

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matter

a substance with both mass and volume

physical properties

any property that can be observed and measured without changing the chemical makeup of the sample

intensive properties

physical properties that do not depend on the size of the sample

extensive properties

physical properties that do depend on the size of the sample

chemical properties

properties that refer to the ability of the substance to undergo a chemical reaction

(pure) substance

matter composed of only 1 type of particle

compound

matter composed of 2 or more types of atoms chemically bonded in a fixed ratio (can be simplified with a chemical reaction & properties of a compound often vary from the properties of the component elements)

law of definite proportions

a compound always contains its elements in a fixed ration based on mass

element

matter composed of only 1 type of atom - may be separate or bonded together into molecules

mixture

matter composed of 2 or more types of particles physically combined (composition varies from sample to sample - no fixed ratio & individual components keep their original properties)

homogeneous

different particles are distributed uniformly (spread out evenly, cannot distinguish between different components, ex. salt water)

heterogeneous

different particles are not distributed uniformly (spread out unevenly, can distinguish between the different components, ex. trail mix)

particle

the smallest “piece” of a sample that can be removed without breaking any chemical bonds

atom

the smallest “piece” of matter that can be identified as a certain element

molecule

2 or more atoms chemically bonded into one unit; the bonded atoms may or may not be different

energy

the ability to do work/make changes happen

electromagnetic energy (light energy)

energy that travels as waves

potential energy

energy that is stored due to an object’s position or shape

kinetic energy

energy of moving particles (faster motion = more kinetic energy)

thermal energy

the total amount of kinetic energy in all the particles of a sample (extensive)

temperature

a measure of the average kinetic energy of the particles in a sample (intensive). NOT a form of energy, just a related measurement

exothermic (exit)

energy is released by the system into the surroundings, energy is treated as an output, energy of the system decreases, energy of the surroundings increases

endothermic (into)

energy is absorbed by the system from the surroundings, energy is treated as an input, energy of the system increases, energy of the surroundings decreases

law of conservation of energy

energy cannot be created or destroyed, only transferred from one material to another or converted from one form to another

thermal equilibrium

both substances reaching the same temperature

system

the substance(s) or object(s) being studied

surroundings

everything else besides the system

specific heat

helps determine how much of a temperature change each material will experience, in addition to mass (the amount of energy needed to raise 1g by 1 degree C)

physical change

any change that does not change the chemical composition of the sample

chemical change

changes to the chemical composition of the sample (ex. new color/odor, bubbling, temperature change, formation of a solid)

law of conservation of mass

mass cannot be created or destroyed, only rearranged (total mass of reactants = total mass of products)

aqueous

dissolved in water

sublimination

physical change - solid turns directly into a gas

deposition

physical change - gas turns directly into a solid

freezing

physical change - liquid turns directly into a solid

melting

physical change - solid turns directly into a liquid

melting point

temp at which a substance melts/freezes

vaporization

physical change - liquid turns directly into a gas

boiling point

temp at which a substance boils/condenses

condensation

physical change - gas turning directly into a liquid

density

amount of mass in a given volume of the substance (d=m/v)

accuracy

measure of how close a measurement comes to the true or actual value

precision

measure of how close a series of measurements are to one another

significant figures

used to convey precision of measurements

percent error

used to show accuracy of an experimental value (measured value-accepted value/accepted value x 100)