CHEM 110 - MIDTERM #3

Question 1

What is the principal quantum number?

Answer 1

Symbol: n
Values: positive values (1, 2, 3)
Property: Orbital energy (size)
The bigger the n value, the larger the orbital

Question 2

What is the angular momentum?

Answer 2

Symbol: l
Values: 0, n-1
Property: orbital shape

Question 3

Orbital shape of l=0

Answer 3

s-orbital (circle)

Question 4

Orbital shape of l=1

Answer 4

p-orbital (dumbell)

Question 5

Orbital shape of l=2

Answer 5

d-orbital (clover)

Question 6

Orbital shape l=3

Answer 6

f-orbital (insane)

Question 7

Collections of orbitals with the same n-value are _____

Answer 7

Shells (ie. 2s and 2p share the same 2nd shell because they both have n=2)

Question 8

Collections of orbitals with the same n & l values are ___

Answer 8

subshells (ie. 2s and 2p are the same subshells)

Question 9

Subshells of n=2

Answer 9

where l=1,0 -> 2p & 2s subshells respectively

Question 10

What is the magnetic quantum number?

Answer 10

symbol: ml
values: + and - l (including 0)
property: orbital orientation in space (number of orbitals in a subshell with a particular l value)
# of ml values can be found with: 2l + 1

Question 11

What is the spin quantum number?

Answer 11

symbol: ms
values: +1/2 or -1/2
property: direction of e- spin

Question 12

if l=0, then how many ml values are there?

Answer 12

ml = 2l + 1 = ml = 1 value where ml=0

Question 13

How many orbitals in l=0?

Answer 13

One orbital where s orbital is present and can only hold 2 electrons

Question 14

How many orbitals in l=1?

Answer 14

3 orbitals where p orbital is present and can only hold 6 electrons

Question 15

How many orbitals in l=2?

Answer 15

5 orbitals where d orbital is present and can only hold 10 electrons

Question 16

How many orbitals in l=3?

Answer 16

7 orbitals where f orbital is present and can only hold 14 electrons

Question 17

How many orbitals in l=4?

Answer 17

9 orbitals where g orbital is present and can only hold 18 electrons

Question 18

Similarities and differences between 1s and 2s orbital?

Answer 18

Have different principal quantum numbers (n=1 vs. n=2); but have the same shell (at l=0). 2s is also larger than 1s in orbital size, but they share the same ml and ms values at l=0. 2s is further away from the the nucleus.

Question 19

Difference between 2px and 2py?

Answer 19

Same n-value, same l value (same size and orbital shape); different orientations (ml=-1 at 2px and ml=0 at 2py).

Question 20

What is an orbital?

Answer 20

electrons with the same values of n, l, and ml (n=3, l=2, ml=-2)

Question 21

Energy of orbitals in a single electron atom rely on __

Answer 21

the principal quantum number (n)

Question 22

Energy of orbitals in a multi-electron atom rely on __

Answer 22

n and l

Question 23

What is the Aufbau principle?

Answer 23

States that the electrons fill in lowest energy orbitals (1s will fill up before 2s and 2p)

Question 24

What is Hund’s Rule?

Answer 24

The most stable arrangement of electrons in subshells is the one with the greatest number of parallel spins (ie. 2p3) - you must put one electron in each orbital before adding the second electron in the orbital

Question 25

Difference between paramagnetic and diamagnetic compounds?

Answer 25

Paramagnetic: unpaired electrons (ie. 2p2)
Diamagnetic: all electrons are paired (2p6)

Question 26

Which EM region has the greatest energy?

Answer 26

Gamma rays

Question 27

Which EM region has the least energy?

Answer 27

Radiowaves

Question 28

Work equation?

Answer 28

W = -P x Change in V (in L)

Question 29

When heat is absorbed it is ____?

Answer 29

Endothermic (+)

Question 30

When heat is released onto the surroundings it is __?

Answer 30

Exothermic (-)

Question 31

First law of thermodynamics equation?

Answer 31

Change in internal energy = heat exchange + work (U = q + w)

Question 32

Negative work = _____

Answer 32

Expansion (-)

Question 33

Positive work = ____

Answer 33

Compression (+)

Question 34

Examples of state functions?

Answer 34

Energy, Enthalpy, Pressure

Question 35

Is work a state function?

Answer 35

no lol

Question 36

Temperature increases with the progression of the reaction = ____ reaction

Answer 36

Exothermic

Question 37

Temperature decreases with progression of reaction = ___ reaction

Answer 37

Endothermic

Question 38

Ideal gas law & thermodynamics =

Answer 38

U = H - RT(n) where:
U = change in internal energy
H= enthalpy
n = number of gas moles products - number of gas moles reactants

Question 39

A combustion reaction is an ____ reaction

Answer 39

Exothermic

Question 40

Standard enthalpy of O2?

Answer 40

0

Question 41

Standard enthalpy of C, graphite?

Answer 41

0

Question 42

Hess’ Law states that ____

Answer 42

enthalpy is a state function

Question 43

Enthalpy of a reaction is equal to the _____ of compounds

Answer 43

molar ratios
(ie. 233 kJ of the reaction = 2 moles of H2 (g))

Question 44

Visible light spectrum?

Answer 44

400-700 nm

Question 45

@ 400 nm the color is?

Answer 45

blue/violet

Question 46

@500 nm the color is?

Answer 46

green

Question 47

@700 nm the color is?

Answer 47

red

Question 48

@400 nm - the wavelength is ____, has a ____ frequency and ____ energy

Answer 48

shorter
higher
higher

Question 49

@700 nm - the wavelength is ____, has a ____ frequency and ____ energy

Answer 49

longer
shorter
lower

Question 50

Excited electron =

Answer 50

going from a higher to lower energy orbit (n=3 -> n =2)

Question 51

Ground state electron =

Answer 51

n=1 (lowest level, closest to nucleus)

Question 52

Emitted electron =

Answer 52

going from lower to higher energy orbit

Question 53

momentum equation

Answer 53

p = mu (mass of electron x velocity)

Question 54

Heisenberg Uncertainty Principle

Answer 54

States that position and momentum are uncertain of an electron

Question 55

Pauli Exclusion Principle

Answer 55

No two electrons in the same atom can have the same quantum number (opposite spins of electrons and no more than two electrons in an orbital)