Physical Science - Chapter 2

indivisible atoms

Atomists "thought that matter was made of ________ and nothing existed between them.

matter

anything that occupies space and has mass

law of definite proportions

the law that states that the masses of chemical substances combine in definite, characteristic integer ratios when forming compounds

particle model of matter

a model that states that all physical matter exists in the form of particles (atoms or molecules) in constant motion

atom

the building block of all matter, consisting of protons, electrons, and (usually) neutrons

molecule

a distinct group of two or more covalently bonded together

pure substance

a material made of only one kind of element or compound; not a mixture

element

a pure substance that consists of atoms with the same atomic number

compound

a pure substance consisting of atoms of two or more different elements that are chemically combined

mixture

a physical combination of two or more substances (elements, compounds, or other mixtures) in a changeable ratio

heterogeneous mixture

a mixture that does not have uniform appearances since the combined are unevenly distributed

homogeneous mixture

a mixture that has a uniform appearance throughout

solid

the state of matter in which particles vibrate in fixed positions, giving a substance a fixed shaped and volume

Particle spacing

close

Particle motion

vibrating in space

Volume

fixed

Shape

fixed

Compressibility

low

Density

high

liquid

the state of matter in which particles are close together but able to move around

Particle spacing

close

Particle motion

able to slide past each other

Volume

fixed

Shape

changes to fill a container from the bottom

Compressibility

low

Density

between that of a solid and that of a gas

Viscosity

the attractive forces between the liquid particles determine the viscosity of a liquid (resistance to flowing)

gas

the state of matter in which particles are far apart, move rapidly, and have little interaction with each other

Particle spacing

widely spread

Particle motion

high speed

Volume

changes to fill the container

Shape

changes to fill the container

Compressibility

high

Density

low

Pressure

due to collisions with container surface

plasma

a gas-like state of matter, formed at very high temperatures, that consists of high-energy ions and free electrons

physical properties

anything a substance that can be observed or measures without altering the substances chemical composition

ductility

the ability of a solid material to be pulled into a wire

malleability

the ability of some solid materials to be hammered or pressed into sheets

conductivity

the ease with which a material allows the transfer of either electrical or thermal energy

luster

the quality of how a material reflects lights

physical changes

any change in matter that does not alter the composition of the substance

chemical properties

a property of a substance that describes how its chemical identity changes in the presence of another substance or under certain conditions

reactivity

the degree to which a material will react with other substances

flammability

the ability of a material to burn in the presence of oxygen

chemical changes

changes that alter the chemical composition of a substance

law of conservation

a fundamental natural law that states that matter can neither be created nor destroyed but can only change forms

melting

the change of state from solid to a liquid

melting point

the temperature at which a solid turns to a liquid

freezing

the change of state from a liquid to a solid

vaporization

the change of state from a liquid to a vapor (gas)

vaporization can occur in two ways

evaporation and boiling

evaporation

the relatively slow form of vaporization in which liquid particles obtain sufficient energy to change to the gaseous state through the random collisions of particles

boiling

the relatively fast form of vaporization in which the energy within a liquid creates higher pressure within the liquid than the air pressure outside the liquid

boiling point

the temperature at which a liquid starts to boil

condensation

the change of state from a vapor to a liquid

sublimation

the change in state directly from a solid to a gas (vapor) without melting first

deposition

the change in state directly from a gas (vapor) to a solid without condensing first

matter

anything that occupies space and has mass

law of definite proportions

the law that states that the masses of chemical substances combine in definite, characteristic integer ratios when forming compounds

particle model of matter

a model that states that all physical matter exists in the form of particles (atoms or molecules) in constant motion

atom

the building block of all matter, consisting of protons, electrons, and (usually) neutrons

molecule

a distinct group of two or more covalently bonded together

pure substance

a material made of only one kind of element or compound; not a mixture

element

a pure substance that consists of atoms with the same atomic number

compound

a pure substance consisting of atoms of two or more different elements that are chemically combined

mixture

a physical combination of two or more substances (elements, compounds, or other mixtures) in a changeable ratio

heterogeneous mixture

a mixture that does not have uniform appearances since the combined are unevenly distributed

homogeneous mixture

a mixture that has a uniform appearance throughout

solid

the state of matter in which particles vibrate in fixed positions, giving a substance a fixed shaped and volume

liquid

the state of matter in which particles are close together but able to move around

Viscosity

resistance to flowing

Pressure

due to collisions with container surface

plasma

a gas-like state of matter, formed at very high temperatures, that consists of high-energy ions and free electrons

physical properties

anything a substance that can be observed or measures without altering the substance’s chemical composition

ductility

the ability of a solid material to be pulled into a wire

malleability

the ability of some solid materials to be hammered or pressed into sheets

conductivity

the ease with which a material allows the transfer of either electrical or thermal energy

luster

the quality of how a material reflects lights

physical changes

any change in matter that does not alter the composition of the substance

chemical properties

a property of a substance that describes how its chemical identity changes in the presence of another substance or under certain conditions

reactivity

the degree to which a material will react with other substances

flammability

the ability of a material to burn in the presence of oxygen

chemical changes

changes that alter the chemical composition of a substance

law of conservation

a fundamental natural law that states that matter can neither be created nor destroyed but can only change forms

melting

the change of state from solid to a liquid

melting point

the temperature at which a solid turns to a liquid

freezing

the change of state from a liquid to a solid

vaporization

the change of state from a liquid to a vapor (gas)

evaporation

the relatively slow form of vaporization in which liquid particles obtain sufficient energy to change to the gaseous state through the random collisions of particles

boiling

the relatively fast form of vaporization in which the energy within a liquid creates higher pressure within the liquid than the air pressure outside the liquid

condensation

the change of state from a vapor to a liquid

sublimation:

the change in state directly from a solid to a gas (vapor) without melting first

deposition

the change in state directly from a gas (vapor) to a solid without condensing first