21 Questions
What is the colour of potassium dichromate?
Dark orange
The amount of light that passes through the control vial affects the gauge in the breathalyzer.
False
What is the estimated cost of impairment-related driving deaths, injuries, and property damage-only crashes in Canada in 2009?
$20.15 billion
The greater the amount of __________ present, the more potassium dichromate is broken down.
alcohol
Match the following colours with the level of alcohol present:
Dark orange = Low level of alcohol Light orange = Moderate level of alcohol Clear = Higher level of alcohol Blue-green = Highest level of alcohol
What type of ions are produced due to the breakdown of potassium dichromate?
Chromium (III) ions
The knob in the breathalyzer must be turned to bring the gauge to its resting place.
True
What is the purpose of the control vial in the breathalyzer?
To compare with the test vial
What is the purpose of the silver nitrate in the Breathalyzer reaction?
To act as a catalyst
The Breathalyzer reaction takes approximately 10 seconds to complete.
False
What is the colour of the potassium dichromate solution?
orange
The reactant that breaks down to produce a colour change in the Breathalyzer reaction is ______________.
potassium dichromate
What is the product of the oxidation of alcohol in the Breathalyzer reaction?
All of the above
The Breathalyzer reaction involves the oxidation of ethanol.
True
Match the following reactants with their corresponding formulas:
Potassium dichromate = 2K2Cr2O7 Sulfuric acid = 8H2SO4 Ethanol = 3CH3CH2OH Silver nitrate = AgNO3
What is the result of the oxidation of alcohol in the Breathalyzer reaction?
Colour change from orange to blue-green
What is the primary reason the Intoxilyzer was developed?
To lower the incidence of operator error and eliminate the need for chemical compounds
A woman will have a lower blood alcohol concentration than a man with the same body weight and drinking the same amount of alcohol.
False
What causes the chemical bonds within a molecule to bend or stretch?
Exposure to infrared light
The Intoxilyzer measures the wavelengths of the chemical bonds in alcohol and the _____________ of infrared light absorbed.
amount
Match the following principles of breathalyzer operation with their descriptions:
Infrared light absorption = Causes chemical bonds to bend or stretch Chemical bonds = Absorb infrared light at different wavelengths Molecule movement = Affected by exposure to infrared light
Study Notes
Potassium Dichromate Reaction
- Potassium dichromate is dark orange, but when broken down, it fades to a lighter orange.
- The greater the amount of alcohol present, the more potassium dichromate is broken down.
- Increasingly larger amounts of alcohol cause the solution to progress from light orange, to clear, to blue-green due to the production of chromium (III) ions.
Breathalyzer Test
- A person suspected of having consumed alcohol blows into the mouthpiece of the Breathalyzer.
- The breath sample goes through an open glass test vial containing a solution of potassium dichromate, sulfuric acid, water, and silver nitrate.
- If alcohol is present, a chemical reaction occurs, producing a colour change.
Chemical Reaction
- The reactants involved in the oxidation of alcohol are potassium dichromate, sulfuric acid, ethanol, water, and silver nitrate.
- The oxidation of alcohol produces chromium (III) sulfate, potassium sulfate, acetic acid, and water.
- The reaction is complete in approximately 90 seconds.
- Silver nitrate is a catalyst and does not change during the reaction.
How Breathalyzer Determines BAC
- When alcohol is oxidized, the reactant (potassium dichromate) breaks down to produce a colour change.
- The test vial is compared to a control vial in a photocell system to quantify the amount of alcohol present.
- The amount of light that passes through each vial produces an electric current, causing a gauge to move.
- The level of alcohol is determined by the amount the gauge must be turned to return to rest.
Did You Know?
- In 2009, impairment-related driving deaths, injuries, and property damage-only crashes in Canada cost $20.15 billion.
Intoxilyzer
- The Intoxilyzer was developed to lower the incidence of operator error and eliminate the need for chemical compounds.
- Molecules are constantly moving, and exposure to infrared light causes changes in this movement.
- The chemical bonds within a molecule absorb infrared light at different wavelengths, which helps to identify the alcohol molecule.
- The amount of infrared light absorbed determines the quantity of alcohol.
Interesting Facts
- Women have a higher blood alcohol concentration than men with the same body weight and drinking the same amount of alcohol due to their higher fat content and lower water content.
This quiz is about the reaction of potassium dichromate with alcohol, which causes a change in color from dark orange to light orange.
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