CEM 141 EXAM 2 MSU NEWEST 2026 ACTUAL EXAM
TEST BANK| MSU CEM 141 EXAM 2 REVIEW WITH 300
REAL EXAM QUESTIONS AND CORRECT VERIFIED
ANSWERS/ ALREADY GRADED A+ (MOST RECENT!!)
An element X exists as diatomic molecules held together by 3 covalent
bonds, while another element Y exists as a 3D network of single
covalent bonds. Element X has a higher atomic mass than element Y.
Which element is most likely to have the highest melting point? -
ANSWER - Y, because all the bonds in the 3D network must break for
the substance to melt
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of CH4 will remain at the end? - ANSWER - 0
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of O2 will remain at the end? - ANSWER - 3
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of H2O will be produced? - ANSWER - 6
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of CO2 will be produced? - ANSWER - 3
pg. 1
,If you started with 16g of methane and 16g of oxygen, how much carbon
dioxide would you produce? - ANSWER - 11
Figure out which is the limiting reactant and use that mass to calculate
the amount of CO2.
16 g methane = 1 mol methane
16 g oxygen = ½ mole O2
since 1 mole CH4 needs 2 mol O2, then O2 is the limiting reactant.
16 g O2 x (1mol Og O2) x (1 mol CO mol O2) x (44 g CO2 /
1mol CO2) = 11 g CO2
If you obtained 5g CO2 what would be the percent yield? - ANSWER -
45.5%
The wavelength of the electron traveling at 5.01 x 10^5 m/s? -
ANSWER - 1.45 x 10^-9 m
The wavelength of the electron that you calculate in question 25 is
closest in size to.... - ANSWER - diameter of a carbon nanotube
If the intensity of a beam of light is increased, this would correspond
to.... - ANSWER - - An increase in the number of photons (considering
light as a particle).
- An increase in the amplitude of the wave (considering light as a wave).
pg. 2
,For a given photocell (a device that uses the photoelectric effect to
generate electricity), blue light will eject electrons, but red light will not.
Why? - ANSWER - Photons of blue light each have enough energy to
eject one electron.
What is the wavelength of light that has a frequency of 3.0 GHz (3 x
10^6 Hz)? - ANSWER - 100 m
What wavelength of light would break a O=O bond (it takes 8.3 x 10^-
19 J to break one bond)? - ANSWER - 240 nm
How does the existence of atoms help explain the conversion of matter?
- ANSWER - The existence of atoms shows that matter is conserved
because the reaction has to be balanced. There cannot just be a random
atom put in or taken out. Both sides have to have the same amount of
atoms.
Atomic absorption spectra are caused by.... - ANSWER - Electrons
moving to higher energy levels and absorbing photons of energy equal to
the energy difference between the levels.
How many core and valence electrons does carbon have? - ANSWER - 2
core, 4 valence
What is the electron configuration of Se? - ANSWER - [Ar] 4s^2 3d^10
4p^4
pg. 3
, Molar Mass - ANSWER - mass of 1 mole in grams
What is the best explanation for a pattern such as those obtained when
X-Rays are diffracted by crystals? - ANSWER - The waves of
electromagnetic radiation arrive in-phase and out of phase at the
detector.
The first ionization energy of an element in the third row (Na-Ar) of the
periodic table is 578 kJ/mol, its second IE is 1820, the 3rd is 2750 and
the 4th is 11600, and the 5th is 14842. Which element do you think this
is? - ANSWER - Aluminum
How many grams of N2 would be required to produce 2.75 moles of
NH3? - ANSWER - 38.5g N2
How many moles of Ca(NO3)2 are in 325g? - ANSWER - 1.98 mole
Ca(NO3)2
How much Carbon Dioxide would be produced if 10 kg of methane are
combusted in excess oxygen? - ANSWER - 27,500 g CO2
How much carbon dioxide would be produced if an excess of methane is
combusted in 10 g oxygen? - ANSWER - 6.9g of CO2
pg. 4
TEST BANK| MSU CEM 141 EXAM 2 REVIEW WITH 300
REAL EXAM QUESTIONS AND CORRECT VERIFIED
ANSWERS/ ALREADY GRADED A+ (MOST RECENT!!)
An element X exists as diatomic molecules held together by 3 covalent
bonds, while another element Y exists as a 3D network of single
covalent bonds. Element X has a higher atomic mass than element Y.
Which element is most likely to have the highest melting point? -
ANSWER - Y, because all the bonds in the 3D network must break for
the substance to melt
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of CH4 will remain at the end? - ANSWER - 0
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of O2 will remain at the end? - ANSWER - 3
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of H2O will be produced? - ANSWER - 6
CH4 + 2O2 ----> 2H2O +CO2
How many molecules of CO2 will be produced? - ANSWER - 3
pg. 1
,If you started with 16g of methane and 16g of oxygen, how much carbon
dioxide would you produce? - ANSWER - 11
Figure out which is the limiting reactant and use that mass to calculate
the amount of CO2.
16 g methane = 1 mol methane
16 g oxygen = ½ mole O2
since 1 mole CH4 needs 2 mol O2, then O2 is the limiting reactant.
16 g O2 x (1mol Og O2) x (1 mol CO mol O2) x (44 g CO2 /
1mol CO2) = 11 g CO2
If you obtained 5g CO2 what would be the percent yield? - ANSWER -
45.5%
The wavelength of the electron traveling at 5.01 x 10^5 m/s? -
ANSWER - 1.45 x 10^-9 m
The wavelength of the electron that you calculate in question 25 is
closest in size to.... - ANSWER - diameter of a carbon nanotube
If the intensity of a beam of light is increased, this would correspond
to.... - ANSWER - - An increase in the number of photons (considering
light as a particle).
- An increase in the amplitude of the wave (considering light as a wave).
pg. 2
,For a given photocell (a device that uses the photoelectric effect to
generate electricity), blue light will eject electrons, but red light will not.
Why? - ANSWER - Photons of blue light each have enough energy to
eject one electron.
What is the wavelength of light that has a frequency of 3.0 GHz (3 x
10^6 Hz)? - ANSWER - 100 m
What wavelength of light would break a O=O bond (it takes 8.3 x 10^-
19 J to break one bond)? - ANSWER - 240 nm
How does the existence of atoms help explain the conversion of matter?
- ANSWER - The existence of atoms shows that matter is conserved
because the reaction has to be balanced. There cannot just be a random
atom put in or taken out. Both sides have to have the same amount of
atoms.
Atomic absorption spectra are caused by.... - ANSWER - Electrons
moving to higher energy levels and absorbing photons of energy equal to
the energy difference between the levels.
How many core and valence electrons does carbon have? - ANSWER - 2
core, 4 valence
What is the electron configuration of Se? - ANSWER - [Ar] 4s^2 3d^10
4p^4
pg. 3
, Molar Mass - ANSWER - mass of 1 mole in grams
What is the best explanation for a pattern such as those obtained when
X-Rays are diffracted by crystals? - ANSWER - The waves of
electromagnetic radiation arrive in-phase and out of phase at the
detector.
The first ionization energy of an element in the third row (Na-Ar) of the
periodic table is 578 kJ/mol, its second IE is 1820, the 3rd is 2750 and
the 4th is 11600, and the 5th is 14842. Which element do you think this
is? - ANSWER - Aluminum
How many grams of N2 would be required to produce 2.75 moles of
NH3? - ANSWER - 38.5g N2
How many moles of Ca(NO3)2 are in 325g? - ANSWER - 1.98 mole
Ca(NO3)2
How much Carbon Dioxide would be produced if 10 kg of methane are
combusted in excess oxygen? - ANSWER - 27,500 g CO2
How much carbon dioxide would be produced if an excess of methane is
combusted in 10 g oxygen? - ANSWER - 6.9g of CO2
pg. 4
