Question 1

What is matter?

Accepted Answer

Any substance with mass and volume

Question 2

What is density?

Accepted Answer

The mass of something divided by its volume

(piecrust has a density of )

Question 3

What are the three common states of matter?

Accepted Answer

Solids, liquids, and gases

Question 4

How do you calculate density?

Accepted Answer

Divide the mass of an object by its volume

Question 5

What is a solid?

Accepted Answer

A state of matter that is structurally rigid and has closely packed atoms

Question 6

What is a liquid?

Accepted Answer

A fundamental state of matter that can flow freely, but has a constant volume (like water)

Question 7

What is a gas?

Accepted Answer

A state of matter that has no fixed shape (unlike a solid) and no fixed volume (unlike a liquid)

Question 8

What is an atom?

Accepted Answer

The smallest particle of ordinary matter that forms a chemical element

(everything is composed of atoms)

Question 9

What are the three main subatomic particles?

Accepted Answer

Protons, neutrons, and electrons

(almost every atom contains these three subatomic particles)

Question 10

What are protons?

Accepted Answer

A type of subatomic particle that is positively charged and located in the atomic nucleus

Question 11

What are neutrons?

Accepted Answer

A type of subatomic particle that has no charge and is located in the atomic nucleus

Question 12

What are electrons?

Accepted Answer

A type of subatomic particle that is negatively charged and is located in the electron cloud

Question 13

What is the atomic nucleus?

Accepted Answer

A dense region in the center of atoms that contains neutrons and protons

Question 14

What is the electron cloud?

Accepted Answer

All the electrons that "orbit" the nucleus of an atom

Question 15

What is an atomic mass unit (amu)?

Accepted Answer

A unit used to measure the weights of single atoms

(since atoms are incredibly small, this unit is also incredibly small; a single atom of nitrogen weighs 14amu)

Question 16

What is an element?

Accepted Answer

A pure substance made entirely of atoms with the same atomic number

Cannot be broken into simpler substances by a chemical reaction

Question 17

What is an atom's mass number?

Accepted Answer

The total number of protons and neutrons in the atomic nucleus

(approximately equal to the atomic mass; oxygen has 8 protons and 8 neutrons, for a mass number of 16)

Question 18

What is atomic mass?

Accepted Answer

The mass of a single atom, expressed in atomic mass units

(approximately equal to the mass number)

Question 19

What is atomic number?

Accepted Answer

The number of protons in an atom

Determines the atom's properties, and which element it is

Question 20

What is the periodic table?

Accepted Answer

A table of all the chemical elements, displayed in rows and columns

Organized in order of atomic number

Question 21

What is an element's symbol?

Accepted Answer

An abbreviation for an element's name

(O for oxygen, He for helium, K for potassium)

Question 22

How do you read an element on the periodic table?

Accepted Answer

The number on the topic is the atomic number, the middle letter is the symbol, and the bottom is the atomic mass

Question 23

What are groups and periods on the periodic table?

Accepted Answer

Groups are vertical columns (similar properties)

Periods are horizontal rows

Question 24

What are metals?

Accepted Answer

Elements that tend to lose electrons to form cations

(usually found on the center and left of the periodic table; low ionization energy)

Question 25

What are nonmetals?

Accepted Answer

Elements that usually gain electrons to form anions

(located on the top right of the periodic table; high ionization energy; dull and will shatter)

Question 26

What are metalloids?

Accepted Answer

Elements with properties in between metals and nonmetals

(found between metals and non-metals on the periodic table)

Question 27

What are moles?

Accepted Answer

A unit for measuring the amount of a substance, since atoms are too small to count normally

(contains  (Avogadro's Number) particles)

Question 28

What is Avagadro's Number?

Accepted Answer

The number of particles (atoms/molecules) in a mole of any substance

(this is constant for every substance; )

Question 29

What is molar mass?

Accepted Answer

The mass of a substance in a single mole of it

Question 30

How do you find the number of moles from the number of particles?

Accepted Answer

Divide the number of particles by Avagadro's Number

Question 31

How do you find the number of particles from the number of moles?

Accepted Answer

Multiply the number of moles by Avagadro's Number

Question 32

How do you find the mass of an element from the number of moles?

Accepted Answer

Find the mass of a single mole of that element (on the periodic table), then multiply that by the number of moles

Question 33

How do you find the number of moles in an element from its mass?

Accepted Answer

Divide the mass by the molar mass of that element (from the periodic table)

Question 34

How do you find the mass of a chemical compound?

Accepted Answer

Multiply the mass of each element by its amount, then add them together

Question 35

How do you do mole equations with compounds instead of elements?

Accepted Answer

First, find the molar mass of the compound, then follow the exact same steps

Question 36

What are isotopes?

Accepted Answer

Types of atoms with the same number of protons (the same element) but different numbers of neutrons

Same atomic number & element type; different atomic mass

Question 37

What is relative abundance?

Accepted Answer

The percentage of an isotope with a specific atomic mass found within naturally occurring samples of an element

( has a relative abundance of 98.90%)

Question 38

What is mass spectrometry?

Accepted Answer

A technique to find the relative abundance of an isotope

Question 39

How do mass spectrometers work?

Accepted Answer

Ionizes atoms and molecules with a high-energy electron beam, then deflects the ions through a magnetic field based on their masses

(technically based on their mass-to-charge (m/z) ratio, not mass, but the charge is usually just 1)

Question 40

What is a mass spectrum of a sample?

Accepted Answer

A graph that shows the relative abundance of ions on the y-axis and their atomic mass on the x-axis

(x-axis is technically the mass-to-charge ratio (m/z), but the charge is usually just 1)

Question 41

How do you find the atomic mass from the relative abundances of isotopes?

Accepted Answer

Multiply the atomic mass of each isotope by its relative abundance, then add them all together

(for chlorine: )

Question 42

How do you recognize an element from its mass spectrum?

Accepted Answer

Find its atomic mass, then see which element is closest to that mass on the periodic table

Question 43

What is the law of constant composition?

Accepted Answer

In any chemical compound, elements always bind in the same proportion with each other

(water is always made of hydrogen and oxygen in a 2:1 ratio)

Question 44

What is the percent composition of a substance?

Accepted Answer

The percent by mass of each element in a compound

(water is 11.11% hydrogen by mass and 88.89% oxygen)

Question 45

What is a compound's empirical formula?

Accepted Answer

The simplest whole-number ratio of atoms in a compound

( and  both have the empirical formula of )

Question 46

What is a compound's molecular formula?

Accepted Answer

A representation of that chemical symbols to indicate elements, and subscripts to indicate the number of atoms

( is the molecular formula for glucose; the lowest ratio of the molecular formula is the empirical formula)

Question 47

How do you find a substance's percent composition?

Accepted Answer

Find the mass of each element in the compound, and divide it by the total mass of the compound

Question 48

How do you find a compound's empirical formula?

Accepted Answer

Start: Assume a 100g sample

Find # of moles: Convert each element from grams into moles, using its atomic mass

Whole number ratio: Divide all the moles by whichever is smallest

Write formula: If all moles are whole numbers, write the moles as the subscript for each element

(if the moles are not whole numbers, you might need to multiply everything by a number)

Question 49

How do you find a compound's molecular formula?

Accepted Answer

Find its empirical formula

Find its atomic mass

Scale the number of atoms per element to match the actual atomic mass to the given atomic mass

Question 50

What is the difference between an element and a compound?

Accepted Answer

An element only consists of a single type of atom ()

A compound consists of multiple types of atoms, linked by covalent or ionic bonds ()

Question 51

What are pure substances?

Accepted Answer

Something that only has a single type of matter

(can be an element or a compound; , , )

Question 52

What are mixtures?

Accepted Answer

Multiple pure substances mixed together

(bonding doesn't occur!)

Question 53

What is the difference between homogenous and heterogeneous mixtures?

Accepted Answer

Homogenous mixtures have a uniform appearance because they are closely mixed (chocolate milk)

Heterogeneous mixtures are not evenly distributed and have multiple components (cereal)

Question 54

What are diatomic elements?

Accepted Answer

Pure elements that form molecules of two bonded atoms

(, , ; Have No Fear Of Ice Cold Beer)

Question 55

What is chromatography?

Accepted Answer

A method for separating solutions through a medium where components move at different rates

Question 56

What is distillation?

Accepted Answer

A method for separating mixtures that are made of liquids

Heats the mixture, which vaporizes the most volatile liquid first, then recondenses it later

Question 57

What is evaporation?

Accepted Answer

A technique to separate a solid from a liquid in a homogenous mixture

The liquid evaporates away, leaving only the solid behind (evaporating water from salt)

Question 58

What is filtration?

Accepted Answer

A separation method to filter mixtures made of particles

Smaller particles pass through the filter, while larger particles get stuck

Question 59

What is magnetic separation?

Accepted Answer

A separation technique that separates magnetic substances from non-magnetic substances using a magnetic

Question 60

What is the Bohr Model?

Accepted Answer

A model of the atom, with a nucleus containing protons/neutrons, and shells containing electrons

Electrons orbit the nucleus in those shells

Question 61

What are electron shells?

Accepted Answer

An orbit around an atom's nucleus, each of which has a different energy level

(closest shell is the 1n shell, second is the 2n shell, etc.)

Question 62

How would an electron change its shell?

Accepted Answer

It would have to absorb/release energy

(absorbing=higher shell; releasing=lower shell)

Question 63

Why are inner shells filled before outer shells?

Accepted Answer

Atoms prefer to have the lowest-energy and most stable configuration

Inner shells have less energy than outer shells

Question 64

What is the valence shell?

Accepted Answer

The outermost shell of an atom, filled with valence electrons

AP Chemistry Flashcards