Spectrometry

Multiple Choice

What is the light that you can see called?

• observatory
• wavelength
• visible light

Multiple Choice

Put the visible light colors in order from longest wavelength to shortest wavelength

• Violet, Indigo, Blue, Green, Orange, Yellow, Red
• Red, Yellow, Green, Orange, Violet, Blue, Indigo
• Red, Orange, Yellow, Green, Blue, Indigo, Violet

Multiple Choice

Which of the following type of electromagnetic radiation has the most energy

• infrared
• ultraviolet
• microwaves
• radiowaves

Multiple Choice

True or False?

When a substance absorbs light it appears coloured

• True

• False

Multiple Choice

True or False?

The colour observed from a substance is the same absorbed colour

• True

• False

Multiple Choice

True or False?

The complement of blue is red

• True

• False

Multiple Choice

True or False?

Colorimetry uses the relationship between colour intensity of a solution and the concentration of the coloured species present.

• TRUE

• FALSE

Multiple Choice

The wavelength chosen for colorimetric analysis is that which gives,,,,,

• maximum absorption for a colourless solution

• minimum absorption for a coloured solution

• maximum absorption for a coloured solution

• minimum absorption for a colourless solution

Multiple Choice

The chosen filter is ______ the colour of the solution being tested.

• complementary to

• same colour as

• darker than

• brighter than

Multiple Choice

An intensely orange coloured solution was analysed using colorimetry. Which of the following statements is not true?

• The concentration of ions in the solution is inversely proportional to the amount of light detected by the detector

• If the colour of the solution is as a result of the ion, a darker solution means more light will be absorbed

• A blue/violet light should be used

• The solution becomes a lighter orange during analysis

Multiple Choice

What is the difference between a colorimeter and a UV-visible spectroscopy?

• Colorimeter has a monochromator

• Spectrophotometer has a light filter

• Spectrophotometer has a monochromator

• Colorimetry doesn't have a light filter

Multiple Choice

True or False?

UV-visible spectrophotometer can be used both qualitatively and quantitatively

• True

• False

Multiple Choice

What is the purpose of a monochromator in UV-Visible Spectroscopy?

• It complements the tungsten lamp

• Selects specific wavelengths to best detect the presence of specific ions

• Produces a spectrum that measures absorbance against a range of frequencies

• Idenitifies which wavelength the sample absorbs

Multiple Choice

For an electron to change from ground state to an excited stated it must...

• Absorb energy
• Release energy

Multiple Choice

When talking about energy levels in an atom, what is an "excited state"?

• The highest energy state of an atom.
• Any level higher than the ground state.
• The lowest energy state of an atom.
• When an atom loses an electron

Multiple Choice

Emission of light from an atom occurs when an electron

• drops from a higher to a lower energy level.
•    jumps from a lower to a higher energy level.   
•    moves within its atomic orbital.
• falls into the nucleus.

Multiple Choice

What is the purpose of a photomultipler in Atomic Emission Spectroscopy?

• Isolates a particular wavelength of light

• Registers the current produced

• Atomises the sample

• Converts light beam into an electrical current

Multiple Choice

True or False?

Atomic Absorption Spectroscopy is used for the analysis of metals.

• True

• False

Multiple Choice

Which of the following is the principle of Atomic Absorption Spectroscopy?

• Radiation is absorbed by non-excited atoms in a vapour state and is excited to higher states

• Medium absorbs radiation and transmitted radiation is measured

• Colour is measured

• Colour is simply observed

Multiple Choice

In Atomic Absorption Spectroscopy, with what material is the cathode in Hollow cathode lamp constructed?

• Tungsten

• Quartz

• Element to be investigated

• Aluminium

Multiple Choice

Which of the following statements about atomic absorption is NOT true?

• It requires that element to be measurement be brought to a non-ionized ground state

• It uses a tungsten lamp as a light source

• It uses a cathode made of the same element being measured

• It measures the absorption of light

Multiple Choice

True or False?

AES is much more versatile than AAS and can detect over 70 elements

• True

• False

Multiple Choice

The main benefit from the development of AAS was its ability to detect:

• a much wider range of substances

• substances with much greater accuracy

• much lower levels of substances

• speed

Multiple Choice

What is a calibration curve?

• Graph of light versus absorbance

• Graph of absorbance versus concentration

• Graph of concentration versus light

• Graph of absorbance volume

Multiple Choice

A solution of a known concentration is a:

• diluted

• standard

• saturated

• concentrated

Multiple Choice

A calibration curve is used in colorimetry to

• visualise the inverse relationship between ion concentration and light absorbance

• determine the concentration of an ion with known absorbance of light

• visualise the proportional relationship between ion concentration and light absorbance

• determine the absorbance of an ionic solution with a known concentration