Exam review study guide

Question 1

Rules for sig figs

Answer 1

Rule 1
- All non-zero digits are significant (Examples- 2,546 (4SF), 978 (3 SF)
Rule 2
- Zeros in front of a number are not significant (Examples- 0202 (3SF) 0.00234 (3SF)
Rule 3
- Zeros between non-zero are significant (Examples - 3,004 (4SF) 0.02305 (4 SF), 7.05 x 10 ^ -5 (3SF)
Rule 4
- Zeros at the end of a number are significant if there is a decimal point in the number (Examples 200 (1SF) 200. (3SF) 0.046700 (5 SF)

Question 2

-Density calculation

Answer 2

Density = Mass (G) / Volume (ml)

Question 3

Precent error calculation

Answer 3

|number experimental D - number of actual D over Number Of actual D| x100

Question 4

Physical property

Answer 4

Quality or condition that can be observed or measured without changing the substance composition

Question 5

Chemical properties

Answer 5

The ability of a substance to undergo specific chemical changes

Question 6

Physical change

Answer 6

Some properties change, but not to chemical composition

Question 7

Chemical change

Answer 7

The chemical composition of the substance changes

Question 8

Element-

Answer 8

composed of atoms, that cannot be broken down into simpler substances by chemical means

Question 9

Compound

Answer 9

A thing that is composed of two or more separate elements

Question 10

Pure substance

Answer 10

A single substance made up of only one particle

Question 11

Mixture-

Answer 11

two or more substances that are mixed together but not chemically combined

Question 12

-Diatomic elements

Answer 12

Molecules composed of two atoms

Question 13

Proton, neutron , electron

Answer 13

Protons
- A particle with a positive electrical charge
Neutrons
- A particle with a neutral charge
Electrons
- A particle with a negative charge

Question 14

What is an atom

Answer 14

The smallest particle of an element that retains its identity in a chemical reaction

Question 15

Cation

Answer 15

An Ion with a positive charge

Question 16

Anion

Answer 16

An Ion with a Negative charge

Question 17

How do you find the charge of an ion

Answer 17

The charge of an Ion is the number of protons minus number of electrons

Question 18

-Isotopes

Answer 18

Isotopes - Are atoms with the same number of protons but different number of neutrons

Question 19

Metals -

Answer 19

Good conductors of electricity, all malleable, almost all are solid

Question 20

Non-metals -

Answer 20

Poor conductors of electricity, most are gasses, any solids are brittle

Question 21

Metalloids

Answer 21

Act like either metals or nonmetals depending on condition

Question 22

• Nuclear Fission -

Answer 22

the process where the nucleus of an atom splits into two or more smaller nuclei and other particles

Question 23

• Nuclear Fusion -

Answer 23

the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy

Question 24

• Radioactive Decay -

Answer 24

the property of some unstable atoms to spontaneously emit nuclear radiation, usually alpha particles or beta particles often accompanied by gamma-rays.

Question 25

-Writing nuclear equations

Answer 25

- The sum of the mass of the reactants = the sum of the , mass of the product - The sum of the changes of the reactants = the sum of the charges of the products

Question 26

-Wavelength, frequency, and energy calculations when given equations.

Answer 26

Wavelength -- distance between corresponding points of two consecutive waves. Frequency -- the number of waves that pass a given point in one second. Short wavelengths = -- high frequency, high energy-- Vise\versa

Question 27

-Electrons and energy levels

Answer 27

In order for an electron to reach the next energy level they need an exact amount of energy

Question 28

S sublevel - Shape - How many electrons - what level does it begin in -

Answer 28

Spherical in shape Can hold 2 electrons Begins in principal energy level 1

Question 29

P sublevel - Shape - How many orbitals - How many electrons - what level does it begin in -

Answer 29

- Dumbbell shaped - Has three different orbitals x, y, and z - Each orientation holds 2 electrons for a total of 6 electrons - Begins in principal energy level 2

Question 30

D sublevel - Shape - How many orbitals - How many electrons - what level does it begin in -

Answer 30

Clover leaf shape Has 5 different orbitals Each holds 2 for a total of 10 electrons Begins in principal energy level 3

Question 31

F sublevel - Shape - How many orbitals - How many electrons - what level does it begin in -

Answer 31

- Crazy complicated shape - 7 different orbitals - Each holds 2 electrons for a total of 14 electrons - Begins at principal energy level 4

Question 32

-Rules for placing electrons in orbitals. (Don’t need to know names, just how they work)

Answer 32

- Electrons occupy the lowest energy orbital first - Each orbital may describe at most two electrons, each with opposite spins - Each degenerate orbital is filled with one electron, all with the same spin, before going Back to pair up

Question 33

- Valence electrons (what they are and knowing how many an element has)

Answer 33

- Outermost electrons (In the highest principal energy level) the last S and P added

Question 34

-Periodic trends (The trend and the WHY behind the trend)\

Answer 34

- The periodic table shows us many trends for the elements, It displays trends for atomic size, ionization energy, ionic size, and electonegativity.

Question 35

-Lewis structures (How to draw for elements and compounds, the terms used for different types of electrons (nonbonding electron pair, unpaired electron, etc.), etc.)

Answer 35

1 - Count up total number of valence electrons for compound (For polyatomics add/subtract electrons based on charge) 2- Draw in the central atom and single bond all of the other atoms to it single bonds = 2 electrons 3 - Fill in valence electrons for bonded atoms 4 - Extra electrons go on the central atom. Each atom should have 8 except for hydrogen 5 - If you don't have enough electrons move unshared pairs to make double or triple bonds 6 - Put square brackets around the diagram for polyatomic ions with the charge written polyatomic ions with the charge written outside the brackets as a subscript

Question 36

-Molecular geometry

Answer 36

- Linear - Bent - Triangle planar - Triangle pyramidal - Tetrahedral

Question 37

Polarity and formal charges

Answer 37

The slight electrical charges on dissimilar atoms are called partial charges

Question 38

-Ionic vs. covalent compounds (what they are made of, properties, etc.)

Answer 38

Ionic - Made up of a nonmetal and metal Covalent - Made up of 2 non metals

Question 39

-Intermolecular force and its impact on physical properties

Answer 39

an attractive force that arises between the positive components (or protons) of one molecule and the negative components (or electrons) of another molecule.

Question 40

-Be able to calculate molar mass for a given chemical

Answer 40

- Atomic mass of an element

Question 41

-Be able to do mole conversions between mass, moles, and particles

Answer 41

1 mole = 6.02 x 10 ^23 representative particles Whatever unit you start with must be at the bottom

Question 42

-Percent composition calculations

Answer 42

- %MASS = element / compound x100

Question 43

-Be able to determine an empirical formula when given percent composition

Answer 43

1. Write percent as a mass (g) 2. Convert to moles 3. Divide by the smaller value 4. If still not whole number multiply 5. Write empirical formula 6. Divide sample mass by empirical molar mass multiply, by empirical formula formula to get molecular formula