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Due No due date Points 100 Questions 30 Time Limit 120 Minutes
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Attempt Time Score LATEST Attempt 1 56 minutes 82.5 out of 100 Score for this quiz: 82.5 out of 100 Submitted Mar 8 at 6:05pm This attempt took 56 minutes. Question 1^0 / 3^ pts Scientific Calculator (https://www.desmos.com/scientific) The pH of a solution of 3.2 x 10 M NaOH is: A. 3. B. 3.7 x 10 C. 4. D. 13 E. 8.
A B
orrect Answerorrect Answer C ou Answeredou Answered D E Question 2^3 / 3^ pts Water is a unique molecule. Which of the following contributes to water’s unique place in the chemical world? The geometry of the molecule The polarity of the O-H bonds The ability of water molecules to hydrogen bond The bond angle of water Correct!Correct! All of the answers are correct Question 3^0 / 3^ pts The bent shape of water is due to ______________. The dipole arrows in a water molecule The electronegativity difference between hydrogen and oxygen ou Answeredou Answered The unequal electron sharing between hydrogen and oxygen
Scientific Calculator (https://www.desmos.com/scientific) The H +^ concentration of a solution is 1.2 x 10 -3M. What is the pH? -1.
-2. Correct!Correct! 2. [ [H +]=1.2 x 10^ -3^ pH=-log[1.2 x 10 -3] = 2.92] Question 6^0 / 3^ pts Scientific Calculator (https://www.desmos.com/scientific) If the K (^) a of an acid is 1.38 x 10 -7, what is the pK^ a? orrect Answerorrect Answer 6.
ou Answeredou Answered 8.
Question 7^3 / 3^ pts List the acids in DECREASING order of strength (strongest to weakest): Nitrous acid (K = 4.0 x 10 ); acetic acid (K = 1.7 x 10 ); phosphoric acid (K = 7.3 x 10 ) a
Nitrous acid, acetic acid, phosphoric acid Acetic acid, nitrous acid, phosphoric acid Correct!Correct! Phosphoric acid, nitrous acid, acetic acid Acetic acid, phosphoric acid, nitrous acid None of the above Question 8^3 / 3^ pts Elemental iodine (I ) is a solid at room temperature. What is the dominant attractive force that exists between I molecules in the solid? 2 2 Correct!Correct! London forces Hydrogen bonds Halogen forces Dipole-dipole forces
B Cl P Correct!Correct! N Question 11^3 / 3^ pts In a bond between P and Cl, there exists a difference in electronegativity resulting in partial positive and partial negative charges. If a dipole arrow were added to this structure, which way would the arrow point? The arrow points from Br toward N Correct!Correct! The arrow points from N toward Br Two arrows; one pointed in each direction There would not be a dipole arrow in this case. None of the above Question 12^3 / 3^ pts The following reaction occurs in glues purchased from hardware stores. Customers use this product to glue plastic together.
Epoxy (l) + hardener (l) Glue (s) + heat given off What is the sign (+ or -) of the change in G and H? A) G is (+) and H is (-) B) G is (-) and H is (-) C) G is (-) and H is (+) D) G is (+) and H is (+) E) None of the above A B Correct!Correct! C D E Question 13^3 / 3^ pts Which of the following is the free-energy change of a reaction? A) G B) S C) H D) G E) All of the above
A B C Correct!Correct! D E Question 16^3 / 3^ pts Which buffer system is used by the blood to maintain pH balance? Vinegar buffer system Acetic acid buffer system Correct!Correct! Bicarbonate buffer system
Water buffers system Formic acid buffer system Question 17^3 / 3^ pts A buffer can neutralize only a certain amount of acid and base. We say that this is its: Buffer limit Buffer range Buffer maintenance Buffer capability Correct!Correct! Buffer capacity Question 18^3 / 3^ pts Is a pH of 7.00 acidic, neutral, or basic? Acidic Correct!Correct! Neutral Basic Both Acidic and Basic Both Neutral and Basic
Correct!Correct! Concentration in molarity The acid dissociation constant, Ka Question 21^3 / 3^ pts Scientific Calculator (https://www.desmos.com/scientific) A pH = 5.0 indicates a concentration of OH (in M) of __________. A. 5 B. 10 C. 10 D. 10 E. 10
1 A B Correct!Correct! C D E Question 22^0 / 3^ pts
A student needs to make a buffer pH of 3.2. Which of the following would best work to buffer at pH 3.2? Formic Acid ou Answeredou Answered Dihydrogen phosphate Propionic acid orrect Answerorrect Answer Tartaric acid All of these Question 23^3 / 3^ pts Which of the following compounds would not be soluble in water? A. NaCl B. OH C. Glucose D. Wax E. All of the above would be soluble
interact in such a way that the nonpolar sections align. This is an example of the _________. Hydrophilic rule orrect Answerorrect Answer Hydrophobic effect Buffering capacity ou Answeredou Answered Hydrogen bonding effect All of the above Question 26^5 / 5^ pts Your Answer: (Short Response) How does the strength of a hydrogen bond compare to the strength of a London Force? Also, how about the strength of a hydrogen bond compared to a dipole-dipole force? Briefly comment on these differences. The strength of a hydrogen bond is 14 kcal while a London force is closer to XX kcal. The strength of a hydrogen bond is much greater than that of a dipole-dipole force, which is closer to XX kcal though it is the second strongest noncovalent force. The differences between these forces is that a hydrogen bond is the strongest non covalent forces.
The hydrogen bond strength is between 12 and 16 kcal, while the London force is generally less than 1 Kcal. A dipole-dipole bond usually is from 0.5 to 2.0 kcal. Also, hydrogen bonds are the strongest non-covalent force, which is illustrated by these numbers. Question 27^5 / 5^ pts Your Answer: Scientific Calculator (https://www.desmos.com/scientific) The K can be calculated by [X ][H ] / [HX] [0.32][0.32] / [0.051] The K = 2.007 or 2 a
Your Answer: The enthalpy change, B_ (fill in symbol), has a ___C_____ value (choose “+” or “-“). The _____D______change, ( S), has a ______E_____ value (choose “+” or “-“). A. (-) B. delta H C. (-) D. entropy E. (-) A) “-“ B) H C) “-“ D) entropy E) “-” Question 30^5 / 5^ pts Support or refute this statement: The following diagram shows a clathrate. (Write “Support” or “Refute,” and then explain in at least two sentences providing one piece of evidence for your answer.)
Your Answer: Support. This diagram helps to demonstrates the hydrophobic effect, which shows how nonpolar and polar regions form form in a "cage" structure, or a clathrate. Water is able to form bonds with itself, shown in this structure above. With polar and nonpolar regions, this ensures a molecule, like water, can continue to bind itself to hydrgren bonds and order themselves according to how the molecule needs. For example, an organism may have this structure around their membrane allowing for the membrane to be hydrophobic. Answer: Support. A clathrate is the organized structure of water around the nonpolar molecules, which is shown here. Quiz Score: 82.5 out of 100
