chemistry - midterm: semester 1

matter >

anything that has mass and volume

______________ you come in contact with is considered some form of ____________

everything, matter

matter (more specific) >

defined as anything that has mass and take up space (volume)

mass >

the measure of the amount of matter

weight >

the measure of the gravitational pull on a substance

are mass and weight the same thing?

no

your water bottle has mass because why?

its heavy

your water bottle has volume because why?

it takes up space

what are the different states of matter?

solid, liquid, gas, and plasma

solid has what?

definitive volume and definitive shape

what kind of forces does a solid have?

strong attractive forces

precipitate >

solid formed from mixing two liquids

liquid has what?

definite volume but not shape

what does liquid move?

rapidly to temporarily overcome strong attractive forces

supernatant of a liquid >

upper layer of fluid above a solid found after a mixture has settled

gas does not have what?

definite volume but not shape

are there any attractive forces in gasses when FAR apart?

no attractive forces

plasma >

4th state of matter

what exactly is plasma?

hot ionized gas

plasma: high temperature physical state in which atom lose or gain electrons?

lose electrons

atom >

smallest particle of matter, which maintains the chemical identity of the element

what is an example of atoms?

sodium atoms

element >

a pure substance, made of only one type of atom

can an element be separated?

cannot be separated unless by using a nuclear reaction

how many known elements are there?

118

compound >

a substance made up of two or more different types of atoms

can a compound be separated?

not by any physical means

how are compounds bonded?

chemically

what is an example of a compound?

sodium chloride, water, NaCl

compounds are always _____ substance and always have a ______________ composition (chemical formula) and are ____________ __________________

pure, fixes, always homogeneous

mixtures >

a combination of two or more kinds (particles) of matter that retains its own identity and properties

can mixtures be separated into their components?

yes, chemically and physically

what are homogeneous called?

solutions

what do homogeneous mixtures have?

uniformed composition, all the same throughout

heterogeneous mixtures are NOT?

uniformed, and ARE made up of various particles (atoms or molecules)

what are the types of chemical separation?

• extraction

• electrolysis

• distillation

• re-crystallization

what are the types of physical separation?

• funneling

• magnetism

• filtration

• evaporation

• boiling

• chromatography

what are properties used to describe?

matter

how can properties be classified?

extensive and intensive

extensive >

depends on the amount of matter in the sample

what are some examples of extensive properties?

mass, volume and calories

intensive properties >

depends on the type of matter in the sample not the amount

what are some examples of intensive properties?

hardness, density, boiling point and color

what does every substance have whether it is an element or compound?

characteristic properties

chemists use properties to categorize substances or help identify ____________ substances

unknown

there are what two kinds of properties and changes?

chemical and physical

physical property >

a characteristic that can be observed or measured without changing the identity of the substance

what are some examples of physical properties?

melting point, boiling point, color, texture and odor

physical change >

a change that does not involve change in the identity of the substance; a change in size, shape or state

what are examples of physical changes?

grinding, cutting, melting, boiling, evaporating, freezing, condensing

are there new substances formed in physical properties and changes?

no

physical changes are changes of ________ which are called what?

state, and it is called phase changes

physical changes are changes of states like liquid to a gas, or a sold to a liquid or a gas to a __________

liquid

phase changes occur at different what for different substances?

temperature

what do phase changes depend on?

heat energy

particles in gas (bullet points) >

• far apart

• no order

• move freely at high speed

• high energy

particles in a liquid (bullets) >

• close together

• no order but more ordered than gas

• move around

• particles slide around each other

• lower energy

particles in a solid (bullets) >

• tightly packed

• ordered

• vibrate in place

• do not move freely

• lowest energy

temperature is the measure of what?

kinetic energy

temperature >

the measure of how hot or cold a substance is

heat energy >

energy transferred from hotter body to cooler body

pressure >

low or high pressure

mass of molecules >

how big or small the molecules are

know phase change diagram

ok

freezing >

when a liquid becomes a solid and the particles slow down

what is another word for freezing?

solidification

what happens when the temperature remains constant?

the phase change of freezing is occurring

the solid and liquid phase exist in ______________ during what stage?

equilibrium, freezing

freezing point >

the temperature at which a substance changes from the liquid phase to the solid phase

during freezing point, melting point and boiling point, temperatures will usually be in which form?

kelvin or degrees celsius

melting >

a solid becomes a liquid because the heat energy is being added to the solid

what happens to the temperature during melting? what happens to the particles?

the temperature rises and the particles speed up

when the temperature is constant, the phase change of __________ is occurring

melting

what two things are in equilibrium during melting?

solid and liquid

melting point >

the temperature at which a substance changes from the solid phase to the liquid phase

boiling >

as heat energy is added to a liquid it changes into a gas

what happens to the temperature during boiling point and what happens to the particles?

it rises and the particles speed up

what is boiling also called?

evaporation

when temperature remains __________, the phase change of boiling is occurring

constant

what exists in equilibrium during the boiling phase?

liquid and gas

boiling point >

the temperature at which a substance changes from the liquid phase to the gas phase

chemical property >

matter will be changed into a new substance after the reaction

what are some examples of chemical properties?

the ability to burn, cook, rust, tarnish and decompose

chemical change >

a change in which one or more substances are converted into a new substance

what is a chemical change also called?

chemical reaction

what are some example of chemical change/reaction?

rotting wood, souring of milk, cooking eggs, grass growing

anytime the word ________ is involved, a chemical change/reaction occurred

react

what do we look for in a chemical reaction?

• evolution of gas (bubbles)

• color change (typically unexpected)

• formation of precipate

• temperature change (emission or absorption of heat or light)

• formation of an odor

energy is _____________ (used) to _______ the bond in __________

absorbed, break, reactants

what is an example of how energy, when absorbed, can break the bond in reactants?

NaCl —> 2Na + Cl(2)

energy is _____________ when new bonds are ___________ in ___________

released, formed, products

what is an example of how when energy is released, new bonds can be formed in products?

2Na + Cl(2) —> 2NaCl

law of conservation of mass (matter) >

no matter what happens in a chemical or physical change, the amount of matter remains the same

in every measurement there is a ________ (quantity) followed by a _____ from a measuring device

number, unit

when we measure, we use a measure tool to compare some dimensions of an object to a ___________

standard

chemists use the metric system and the international system of units (S I) for measurement when they…

• measure quantities

• do experiments

• solve problems

what is the metric system measurement for volume?

liter (L)

when do we use liters in volume?

when it is liquid

what measurement used in S I for volume?

cubic meter m³

when do we use cubic meters in volume?

when it is solid