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Physical Science Questions, Part 2

11. Identify one of the fundamental concepts expressed by Ohm's Law:

  1. The amount of current passing through a conductor between two points is directly proportional to the voltage between those two points.
  2. The amount of current passing through a conductor between two points is inversely proportional to the voltage passing between those two points.
  3. The sum of all of the voltage differences in a circuit must be equal to zero.
  4. The sum of all of the voltage differences in a circuit is equal to the amount of current.

12. Identify the statement that correctly explains Kirchhoff's first law:

  1. At any given point in an electrical circuit the sum of the currents flowing towards that point will be equal to the sum of the currents flowing away from that point.
  2. The sum of all of the voltage differences in any circuit must equal zero.
  3. At any given point in an electrical circuit, the sum of the currents flowing towards that point will never be equal to the sum of the currents flowing away from that point.
  4. The sum of all of the voltage differences in any circuit must equal greater than zero.

13. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine the approximate pKa of Substance A:

  1. 0.000063, which is equal to 6.3 x 10-5
  2. 4.20, which is equal to -log 6.3 x 10-5
  3. -4.20, which is equal to log 6.3 x 10-5
  4. 63.00, which is equal to 6.3 x 10

14. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine the approximate pKa of Substance B:

  1. 0.00000001, which is equal to 10-7
  2. 7.0, which is equal to log 107
  3. -7.0, which is equal to -log 107
  4. 10,000,000, which is equal to 107

15. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine the approximate pKb of Substance C:

  1. 0.000018, which is equal to 1.8 x 10-5
  2. -4.75, which is equal to log 1.8 x 10-5
  3. 4.75, which is equal to -log 1.8 x 10-5
  4. 18, which is equal to 1.8 x 10

16. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine the approximate pKa of Substance C:

  1. -4.75
  2. 4.75
  3. 9.25
  4. 18.75

17. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5and a pH of greater than 7. Determine whether Substance A is a:

  1. Strong Acid
  2. Weak Acid
  3. Strong Base
  4. Weak Base

18. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine whether Substance B is a:

  1. Strong Acid
  2. Weak Acid
  3. Strong Base
  4. Weak Base

19. A forensics laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and the amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine whether substance C is a:

  1. Strong Acid
  2. Weak Acid
  3. Strong Base
  4. Weak Base

20. A forensic laboratory is attempting to determine the acidic or basic strength of three substances found at a crime scene in order to determine which substance was used to corrode a lock. In order to determine which substance was actually used to corrode the lock, the scientists test the pH of each substance and amount of dissociation for each substance. After the tests are completed, the scientists determine that Substance A has a Ka of 6.3 x 10-5 and a pH of less than 7, Substance B has a Ka of approximately 107 and a pH of less than 7, and Substance C has a Kb of 1.8 x 10-5 and a pH of greater than 7. Determine the substance that was most likely used to corrode the lock:

  1. Substance A
  2. Substance B
  3. Substance C
  4. It is impossible to determine which substance was used from the information.




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