CHEM 101: Lab Exam Pre Test
Questions All Solved Correctly 2025-
2026 Updated.
What type of spectrum is emitted by gaseous discharge tubes? - Answer A discontinuous
spectrum
White light from the sun emits what type of spectrum? - Answer A continuous spectrum
from red to violet
How are photons emitted in discharge tubes? - Answer As the excited atom returns to a
lower energy state, photons are emitted
What are 3 common applications of light emission by elements? - Answer 1) The flame test
2) Fireworks
3) Office fluorecent lights
The spectrometer gets data on ________________ - Answer absorption
The plot of _______________ against ___________________ of incident light is called a
spectrum - Answer Absorption, wavelength
The shorter the wavelength the _____________ the energy - Answer higher
Transitions with the smallest energy change will have the longest wavelength, explain why this
is? - Answer This is because energy is inversely proportional to wavelength
What are the two posssible reasons for an object to show a particular colour? - Answer 1)
THe absorbance of all wavelengths but those of said colour
2) THe absorbance of the complimentary colour
Why did the smarties show the colour they did? - Answer Because they absorbed the
complimentary colour
, What are the two ways you can recycle scrap aluminum? - Answer By melting it or a
chemical reaction
Al(OH)3 is atmospheric, what does this mean? - Answer It can react either with an acid or
with a base
What does a fertilizer label of 10-20-20 means - Answer The guaranteed percent nitrogen,
phosphoric acid, and potash in the fertilizer
What are the other products of the reaction that creates Cu(NO3)2? - Answer NO and H2O
On exposure to air, what happens to NO - Answer It forms NO2 and becomes a posonus
reddish brown gas
What is the filtrate? - Answer The liquid that passes through the filter into the filter flask
Efflorescent - Answer Hydrates that spontaneously lose water to the atmosphere
How does efflorescence occur? - Answer This loss of water occurs because the vapor
pressure of water exerted by efflorescent solids is greater that that of the vapor pressure of
water in the surrounding atmosphere
Hygroscopic - Answer Hydrates that spontaneously absorb water from the atmosphere
Why may Hygroscopic hydrates, that spontaneously absorb water from the atmosphere, be
termed dessicates? - Answer Because they are used a dry liquid/gas
Deliquescent - Answer When a compound absorbs water from the atmosphere so strongly
that it dissolves in its own hydration
How do you go about removing water of crystilization from a hydrate that is stable at room
temperature? - Answer It must be heated to a temperature at which the vapour pressure of
the water exerted by the solid hydrate exceeds the partial pressure of water in the atmosphere
above the solid
Questions All Solved Correctly 2025-
2026 Updated.
What type of spectrum is emitted by gaseous discharge tubes? - Answer A discontinuous
spectrum
White light from the sun emits what type of spectrum? - Answer A continuous spectrum
from red to violet
How are photons emitted in discharge tubes? - Answer As the excited atom returns to a
lower energy state, photons are emitted
What are 3 common applications of light emission by elements? - Answer 1) The flame test
2) Fireworks
3) Office fluorecent lights
The spectrometer gets data on ________________ - Answer absorption
The plot of _______________ against ___________________ of incident light is called a
spectrum - Answer Absorption, wavelength
The shorter the wavelength the _____________ the energy - Answer higher
Transitions with the smallest energy change will have the longest wavelength, explain why this
is? - Answer This is because energy is inversely proportional to wavelength
What are the two posssible reasons for an object to show a particular colour? - Answer 1)
THe absorbance of all wavelengths but those of said colour
2) THe absorbance of the complimentary colour
Why did the smarties show the colour they did? - Answer Because they absorbed the
complimentary colour
, What are the two ways you can recycle scrap aluminum? - Answer By melting it or a
chemical reaction
Al(OH)3 is atmospheric, what does this mean? - Answer It can react either with an acid or
with a base
What does a fertilizer label of 10-20-20 means - Answer The guaranteed percent nitrogen,
phosphoric acid, and potash in the fertilizer
What are the other products of the reaction that creates Cu(NO3)2? - Answer NO and H2O
On exposure to air, what happens to NO - Answer It forms NO2 and becomes a posonus
reddish brown gas
What is the filtrate? - Answer The liquid that passes through the filter into the filter flask
Efflorescent - Answer Hydrates that spontaneously lose water to the atmosphere
How does efflorescence occur? - Answer This loss of water occurs because the vapor
pressure of water exerted by efflorescent solids is greater that that of the vapor pressure of
water in the surrounding atmosphere
Hygroscopic - Answer Hydrates that spontaneously absorb water from the atmosphere
Why may Hygroscopic hydrates, that spontaneously absorb water from the atmosphere, be
termed dessicates? - Answer Because they are used a dry liquid/gas
Deliquescent - Answer When a compound absorbs water from the atmosphere so strongly
that it dissolves in its own hydration
How do you go about removing water of crystilization from a hydrate that is stable at room
temperature? - Answer It must be heated to a temperature at which the vapour pressure of
the water exerted by the solid hydrate exceeds the partial pressure of water in the atmosphere
above the solid
