When suspected drunk drivers are tested with a Breathalyzer the alchol (ethanol) in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate: 3 C H 3 C H 2 O H ( a q ) + 2 C r O 7 2 − ( a q ) + 16 H + ( a q ) → 3 C H 3 C O 2 H ( a q ) + 4 C r 3 + ( a q ) + 11 H 2 O ( l ) The color of the solution changes because same of the orange C r 2 O 7 2 − is converted to the green C r 3 + The Breathalyzer measures the color change and produces a meter reading calibrated in blood alcohol content. (a) What is P for the reaction if the standard half-cell potential for the reduction of acetic acid to ethanol is 0.05 8 V? (b) What is the value of E for the reaction when the concentrations of ethanol, acetic acid, C r 2 O 7 2 − , and C r 3 + are 1.0 M and the pH is 4.00?
When suspected drunk drivers are tested with a Breathalyzer the alchol (ethanol) in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate: 3 C H 3 C H 2 O H ( a q ) + 2 C r O 7 2 − ( a q ) + 16 H + ( a q ) → 3 C H 3 C O 2 H ( a q ) + 4 C r 3 + ( a q ) + 11 H 2 O ( l ) The color of the solution changes because same of the orange C r 2 O 7 2 − is converted to the green C r 3 + The Breathalyzer measures the color change and produces a meter reading calibrated in blood alcohol content. (a) What is P for the reaction if the standard half-cell potential for the reduction of acetic acid to ethanol is 0.05 8 V? (b) What is the value of E for the reaction when the concentrations of ethanol, acetic acid, C r 2 O 7 2 − , and C r 3 + are 1.0 M and the pH is 4.00?
Solution Summary: The author explains that the standard half-cell potential for the reduction of acetic acid to ethanol is 0.058V. The EMF of the electrochemical cell can be calculated with the help of electrode reduction potential values.
When suspected drunk drivers are tested with a Breathalyzer the alchol (ethanol) in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate:
3
C
H
3
C
H
2
O
H
(
a
q
)
+
2
C
r
O
7
2
−
(
a
q
)
+
16
H
+
(
a
q
)
→
3
C
H
3
C
O
2
H
(
a
q
)
+
4
C
r
3
+
(
a
q
)
+
11
H
2
O
(
l
)
The color of the solution changes because same of the orange
C
r
2
O
7
2
−
is converted to the green
C
r
3
+
The Breathalyzer measures the color change and produces a meter reading calibrated in blood alcohol content. (a) What is P for the reaction if the standard half-cell potential for the reduction of acetic acid to ethanol is 0.05 8 V? (b) What is the value of E for the reaction when the concentrations of ethanol, acetic acid,
C
r
2
O
7
2
−
, and
C
r
3
+
are 1.0 M and the pH is 4.00?
If you want to produce 250 mg of aspirin (C9H8O4) from the reaction of C7H6O3 and C4H6O3, what is the minimum amount of C7H6O3 that is needed?
2C7H6O3(s) + C4H6O3(l) -> 2C9H8O4(s) + H2O(l)
2.50 x 102 g
6.21 x 103 g
1.42 x 10-1 g
1.92 x 10-1 g
1.92 x 102 g
Cyanobacteria are chemosynthetic organisms that reside deep in the ocean near hydrothermal vents. Archeoglobus, one of these types of cyanobacteria, uses the pathway shown in the chemical equation.
4H2 + SO42− + 2H+ → H2S + 4H2O
Based on this equation, which explanation best describes how the process of chemosynthesis in bacteria differs from photosynthesis, and why can this process occur in the absence of oxygen?
Chemosynthesis uses H2 as an energy source, while photosynthesis uses the Sun as an energy source.
Chemosynthesis uses H+ as an energy source, while photosynthesis uses the Sun as an energy source.
Chemosynthesis reduces a sulfate molecule in the absence of oxygen and light, while photosynthesis depends on light to reduce carbon dioxide.
Chemosynthesis oxidizes a sulfate molecule in the absence of oxygen and light, while photosynthesis depends on light to reduce carbon dioxide.
At constant pressure and 25°C, the ΔrH° for the following reaction is –1560 kJ/mol
C2H6(g) + 3.5O2(g) → 2CO2(g) +0.5 H2O(l)
What is the enthalpy change for the oxidation of 5 g of C2H6?
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Calorimetry Concept, Examples and Thermochemistry | How to Pass Chemistry; Author: Melissa Maribel;https://www.youtube.com/watch?v=nSh29lUGj00;License: Standard YouTube License, CC-BY