Chemistry Midyear Review (Questions)

Front 1

Difference between an observation and inference?

Back 1

an observation is what is seen while an inference is an assumption made on top of that observation

Front 2

Units used to measure mass?

Back 2

grams

Front 3

Units used to measure volume?

Back 3

cubic centimeters or Liters

Front 4

What is density?

Back 4

(mass/volume) - represents the amount of the substance compacted into a certain volume of that substance

Front 5

All _____ numbers are significant.

Back 5

nonzero (Ex. 3.4grams has two sig figs)

Front 6

Zeros lying between nonzero numbers are ________

Back 6

significant (Ex. 3.04grams has two sig figs)

Front 7

Zeros to the left of all the nonzero digits are ________

Back 7

not significant (Ex. 0.0034grams has two sig figs)

Front 8

Zeros to the right of all the nonzero digits are _______ if there's a _______ written in the number

Back 8

1) significant
2) decimal point
3) Ex. 1000 has one sig fig, whereas .1000 has four sig figs

Front 9

Numbers in scientific notation have the _______ of sig figs as ______ part of the number _______

Back 9

1) same number
2) the decimal
3) before x10
4) Ex. 4.30 x 10^5 has three sig figs

Front 10

Sig Figs: Addition and Subtraction

Back 10

answer has same number of sig figs to the right of the decimal as the added number with the fewest does (Ex. 3.4 + 5.02301 = 8.42301 ~ round to 8.4 b/c 3.4 has one sig fig to the right of the decimal)

Front 11

Sig Figs: Multiplying & Dividing

Back 11

answer should have the same number of sig figs as the original number with the fewest (Ex. 1.22 x 3.487 = 4.25414 ~ round to 4.25 b/c 1.22 has only three sig figs)

Front 12

What properties can be used to identify substances?

Back 12

density, melting/boiling point, solubility, physical properties

Front 13

What properties cannot be used to identify substances?

Back 13

mass and volume

Front 14

States of Matter: Solid

Back 14

definite shape and volume

Front 15

States of Matter: Liquid

Back 15

flows, has a fixed volume, takes the shape of its container

Front 16

States of Matter: Gas

Back 16

takes both the shape and volume of its container and is easily compressed

Front 17

Difference between and pure substance and a mixture?

Back 17

a pure substance is uniformly made up of the same element while a mixture is a physical blend of different substances

Front 18

Homogenous vs. Heterogenous

Back 18

1) Homo - completely uniform composition; components evenly distributed throughout the sample

2) Hetero - not uniform in composition; contents not spread evenly throughout sample

Front 19

What are the measurable properties of gas?

Back 19

volume, temperature, pressure, mass, moles

Front 20

Assumption #1 of Kinetic Theory:

Back 20

there are a lot of individual molecules however those molecules are spread out widely

Front 21

Assumption #2 of Kinetic Theory:

Back 21

molecules move in random directions at a constant speed

Front 22

Assumption #3 of Kinetic Theory:

Back 22

molecules only exert force when they collide elastically with their container or other molecules

Front 23

Assumption #4 of Kinetic Theory:

Back 23

molecules obey Newton's laws of motion

Front 24

What is the Ideal Gas Law?

Back 24

(P1 x V1) / T1 = (P2 x V2) / T2

Front 25

Difference between an element and a compound?

Back 25

an element is made up of only one type of atom and has unique properties while a compound is made up of different types of atoms with and has its own unique properties

Front 26

How does a compound of two elements differ from a homogenous mixture of the two elements?

Back 26

the compound has properties unique of its components and can only be separated by a chemical reaction; the homogenous mixture takes on the properties of its components and can be separated by using those properties

Front 27

What is an ion?

Back 27

an atom or group of atoms that is +/- in charge

Front 28

How to write the chemical formulas for ionic compounds?

Back 28

have enough of each element so that the charges will cancel out and be zero

Front 29

Scientific Law

Back 29

a general statement about the way the world has been observed to work (eg. what goes up must come down)

Front 30

Scientific Theory

Back 30

an explanation that successfully accounts for scientific observations

Front 31

Law of Constant Proportions

Back 31

in samples of any chemical compound, the masses of the elements are always in the same proportions

Front 32

Law of Multiple Proportions

Back 32

elements combine to form compounds in ratios of small whole numbers

Front 33

Tenet #1 of Dalton's Atomic Theory:

Back 33

all elements are composed of tiny indivisible particles called atoms

Front 34

Tenet #2 of Dalton's Atomic Theory:

Back 34

atoms of the same element are identical and they are unique from those of another element

Front 35

Tenet #3 of Dalton's Atomic Theory:

Back 35

atoms can physically mix or chemically combine in small whole number ratios to form compounds

Front 36

Tenet #4 of Dalton's Atomic Theory:

Back 36

chemical reactions occur when atoms are separated, joined, or rearranged. atoms never change into those of another element though

Front 37

How did Dalton come to his conclusions in atomic theory?

Back 37

he studied the ratios in which elements combine in chemical reactions

Front 38

J.J. Thomsen

Back 38

created the Cathode Ray Tube which showed electrons to be negatively charged

Front 39

Ernst Rutherford

Back 39

created the "alpha particle shooter" which showed that there was something of considerable mass sitting in the center of the electron "cloud"

Front 40

What was the major change in Dalton's atomic theory?

Back 40

that atoms are divisible into smaller sub-atomic particles

Front 41

Protons

Back 41

the positively charged sub-atomic particles in the nucleus

Front 42

Neutrons

Back 42

the other non-charged sub-atomic particle in the nucleus

Front 43

Electrons (e-)

Back 43

the negatively charged sub-atomic particles that orbit the nucleus

Front 44

Nucleus

Back 44

the positively charged core of the atom made up of protons and neutrons

Front 45

Atomic Number vs. Atomic Mass

Back 45

1) Number - number of protons
2) Mass - protons + neutrons

Front 46

Chemical Formula vs. Formula Units vs. Molecular Formulas

Back 46

1) Chemical - kinds and numbers of atoms in the smallest unit of the substance
2) Form Unit - used with ionic compounds; lowest whole-number ratio of ions
3) Molecular - kinds and numbers of atoms present in a molecule of a compound

Front 47

Where are metals and non-metals located on the periodic table?

Back 47

1) Metals - left of squiggly line
2) Non-metals - right of squiggly line

Front 48

How to differentiate molecular and ionic compounds?

Back 48

molecular are made of all non-metals while ionic are made of metals and non-metals

Front 49

Greek Prefixes: 1

Back 49

mono

Front 50

Greek Prefixes: 2

Back 50

di

Front 51

Greek Prefixes: 3

Back 51

tri

Front 52

Greek Prefixes: 4

Back 52

tetra

Front 53

Greek Prefixes: 5

Back 53

penta

Front 54

Greek Prefixes: 6

Back 54

hexa

Front 55

Greek Prefixes: 7

Back 55

hepta

Front 56

Greek Prefixes: 8

Back 56

octa

Front 57

Why balance equations?

Back 57

because we need to make sure that the masses match up because of the law of conservation of mass

Front 58

What is a mole?

Back 58

6.02 x 10^23; unit of measure like "a dozen"

Front 59

How are atomic mass and molar mass related?

Back 59

they are equivalent

Front 60

Why aren't atomic masses whole numbers?

Back 60

because it is the average of the mass of all the elements isotopes

Front 61

How is the percent composition of a compound related to the law of Constant proportions?

Back 61

in any compound, one of the elements will always make up a certain percentage of the compound

Front 62

How do you calculate the molecular mass of a compound?

Back 62

add together the atomic masses of all the elements

Front 63

Hydrated Crystal

Back 63

a crystal that can hold a significant amount of water

Front 64

Empirical Formula vs. Molecular Formula

Back 64

1) Empirical - lowest ratio of one to the other
2) Molecular - ratio in the compound

Front 65

Limiting Reagent

Back 65

the reactant that will run out first

Front 66

How to determine the limiting reagent?

Back 66

the reactant you have the least of