lab exam

Question 1

when do we get emission spectra

Answer 1

when electrons drop from a higher energy level to a lower energy level and emit a photon

Question 2

when do we get absorption spectra

Answer 2

when light passes through an atom and gets absorbed at certain wavelengths

Question 3

when are electrons emitted due to the photoelectric affect

Answer 3

when the frequency of incident light is greater than the threshold frequency

Question 4

when are electrons emitted due to the photoelectric affect

Answer 4

when the frequency of incident light is greater than the threshold frequency

Question 5

what is the energy of the photons related to?

Answer 5

the frequency, the greater the frequency the higher the energy of the photons

Question 6

what is the intensity of incident light related to

Answer 6

it is directly related to the number of photons emitted

Question 7

what is the chemical formula for ascorbic acid (Vitamin C)

Answer 7

C6H8O6

Question 8

what is the heat capacity of an object

Answer 8

the amount of heat needed to change it’s temperature by 1 degree

Question 9

what can a system contain? what can it not?

Answer 9

it can contain internal energy, it cannot contain heat or work

Question 10

what is heat

Answer 10

energy in transition

Question 11

what spectra series corresponds to transitions from n(initial) to a n(final) of 1

Answer 11

the lyman series

Question 12

what spectra series corresponds to transitions from higher levels to n(final) = 2

Answer 12

balmer series

Question 13

what spectra series corresponds to transitions from higher energy levels to n(final) = 3

Answer 13

paschen series

Question 14

in which directions (across, up and down) does atomic radii increase

Answer 14

right to left, and top to bottom

Question 15

in which directions (across, up and down) does metallic character increase

Answer 15

right to left and down a column

Question 16

what happens during ionic bonding

Answer 16

a transfer of electrons

Question 17

what happens during covalent bonding

Answer 17

electrons are shared equally

Question 18

what is electronegativity

Answer 18

the measure of an atom’s ability to attract the bonding electron density to itself

Question 19

in which directions (across, up and down) does electronegativity increase

Answer 19

left to right and bottom to top

Question 20

when is a compound mostly ionic

Answer 20

when the electronegativity difference is greater approximately 2

Question 21

what is the measure of an atoms ability to attract the bonding density towards itself called

Answer 21

electronegativity

Question 22

which type of IMF is the strongest

Answer 22

ion-dipole

Question 23

order the IMFs from weakest to strongest

Answer 23

london dispersion < dipole dipole < h bonding < ion-dipole

Question 24

which is has good conductivity in water- an ionic or covalent substance? why?

Answer 24

ionic - ionic compounds can dissociate into ions

Question 25

what are ionic oxides

Answer 25

basic anhydrides

Question 26

what are covalent oxides

Answer 26

acidic anhydrides

Question 27

what are the two factors that affect the position of equilibrium

Answer 27

1) the ability of R to draw electrons from O-H 2) the stability of the anion (the further right the stronger the acid

Question 28

t/f like dissolves like

Answer 28

t

Question 29

what is molar heat capacity

Answer 29

the amount of heat required to raise the temp of 1 mol of a substance per unit of mol

Question 30

is pressure constant in a calorimeter

Answer 30

yes

Question 31

why do we find the extrapolated temp from the graph of a calorimeter experiment

Answer 31

because calorimeters are not 100% efficient

Question 32

how do you draw the line on a calorimeter graph

Answer 32

draw from the end point to the max, then extend to the y axis

Question 33

is heat capacity (C) intensive or extensive? why?

Answer 33

intensive- since the substance does not matter

Question 34

is specific heat capacity intensive or extensive? why?

Answer 34

extensive- the amount of substance is needed to calculate c

Question 35

is molar heat capacity intensive or extensive? why?

Answer 35

extensive- the amount of substance is needed to calculate Cm

Question 36

what happens when excited atoms return to a lower state

Answer 36

a photon is emitted

Question 37

what are applications of emission line spectra

Answer 37

flame test to identify elements, fireworks, florescent lights

Question 38

in what order does wavelength of the visible spectrum increase

Answer 38

violet

Question 39

what is the equation for the transition between energy levels

Answer 39

delta E = Efinal - Einitial = -Z^(2)Rh( (1/nf^2) + (1/ni^2))

Question 40

what is a spectrometer used for

Answer 40

obtain the values of absorption (A) as the wavelength of the incident light is varied.

Question 41

what does a larger A value obtained from a spectrometer mean

Answer 41

more of the incident light is absorbed

Question 42

what does a longer wavelength of emitted photon correspond to

Answer 42

a lower energy

Question 43

which emitted photon has the shortest wavelength

Answer 43

n = inf, it has the largest change in energy

Question 44

what is the most abundant metal

Answer 44

Al

Question 45

what is the main ore of Al

Answer 45

bauxite

Question 46

how is Al extracted

Answer 46

via the hall heroult process

Question 47

what is the ratio of reactants called

Answer 47

stoichiometric factor

Question 48

what is the stoichiometric point

Answer 48

the equivalence point

Question 49

where is equivalence point of a titration

Answer 49

when chemically equivalent quantities of reactants have been reached

Question 50

where is the endpoint of a titration

Answer 50

when the colour change has been observed

Question 52

what colour does lithium chloride burn

Answer 52

red

Question 53

what colour does barium chloride burn

Answer 53

green

Question 54

when one KIO3 particle reacts with ascorbic acid how many ascorbic acid molecules react

Answer 54

3

Question 55

what is the formula for ascorbic acid

Answer 55

C6H8O6

Question 56

what is ascorbic acid

Answer 56

vitamin c

Question 57

in what ratio does vitamin c react with NaOH

Answer 57

1:1