CHEM 101: LAB EXAM QUESTIONS AND
ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT RATED A+
Question: What specific category of light spectrum is produced and observed
when viewing gaseous discharge tubes?
Answer: ✔✔ A discontinuous spectrum (also known as an emission line spectrum)
Question: What type of spectrum is generated by white light originating from the
sun or an incandescent bulb?
Answer: ✔✔ A continuous spectrum containing all unbroken blended colors from
red to violet
Question: What is the atomic mechanism that causes photons to be released inside
a gas discharge tube?
Answer: ✔✔ Photons are emitted when electrons in excited, high-energy atoms
drop back down to a lower, more stable energy state or ground state.
Question: What are three everyday or laboratory applications that rely on the
emission of light by excited chemical elements?
Answer: ✔✔
1. Chemical flame tests used for element identification
2. The vibrant colors produced in fireworks displays
3. Commercial or office fluorescent lighting fixtures
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 is the main ore of Al? What is it composed of? -ANSWER......The main ore
of Al is bauxite, a hydrate of Al2O3, mixed with oxides of iron, silicon, and
titanium
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
ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT RATED A+
Question: What specific category of light spectrum is produced and observed
when viewing gaseous discharge tubes?
Answer: ✔✔ A discontinuous spectrum (also known as an emission line spectrum)
Question: What type of spectrum is generated by white light originating from the
sun or an incandescent bulb?
Answer: ✔✔ A continuous spectrum containing all unbroken blended colors from
red to violet
Question: What is the atomic mechanism that causes photons to be released inside
a gas discharge tube?
Answer: ✔✔ Photons are emitted when electrons in excited, high-energy atoms
drop back down to a lower, more stable energy state or ground state.
Question: What are three everyday or laboratory applications that rely on the
emission of light by excited chemical elements?
Answer: ✔✔
1. Chemical flame tests used for element identification
2. The vibrant colors produced in fireworks displays
3. Commercial or office fluorescent lighting fixtures
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 is the main ore of Al? What is it composed of? -ANSWER......The main ore
of Al is bauxite, a hydrate of Al2O3, mixed with oxides of iron, silicon, and
titanium
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
