Deck 2: The Nature of Moleculars and the Properties of Water

Question 1

Which chemical group forms hydrogen bonds with water and is most likely to explain why sugars dissolve well in water?

A) -C-H
B) -N-H
C) -C-C
D) -O-H

Answer 1

-O-H

Question 2

An oxygen atom in water has two covalent bonds with hydrogen atoms and two unpaired electrons. How many hydrogen bonds can a water molecule form?

A) 1
B) 2
C) 3
D) 4
E) 5

Answer 2

4

Question 3

The half-life of Carbon-14 is approximately 5,700 years. Using this information scientists have been able to determine the age of some artifacts left by humans. A scientist wants to know approximately how old a piece of wood was that she found on the floor in an old cave that had recently been discovered. She removed the wood (with permission) to her laboratory. Her wood sample contained 2 grams of Carbon-14. If the age of the wood was determined to be 22,800 years old, how much Carbon-14 originally existed in this piece of wood?

A) 32 grams
B) 16 grams
C) 12 grams
D) 8 grams
E) 4 grams

Answer 3

32 grams

Question 4

Water is most dense and thus heaviest at 4^oC. At 0^oC, ice forms and can float on liquid water. Suppose ice were most dense at 0^oC. What would happen in a lake?

A) The ice would cover the bottom of the aquatic system and would build up in layers over time.
B) Ice would not form because solids are always less dense than liquids.
C) The ice would cover the surface of the aquatic system and would never melt.
D) The cold temperatures and the subsequent ice formation would prevent hydrogen bonds from forming between the water molecules, thus causing the existing ice crystals to become disassociated from each other.

Question 5

Your dog becomes ill and you rush him to the veterinarian's office. A technician draws blood from your dog's leg for a vet-ordered lab test. After a few minutes the lab results are given to the vet, who immediately grabs a bottle from a shelf and begins to fill a syringe with an unknown fluid. You inquire about the fluid, and the vet informs you that the fluid is necessary to manage your dog's metabolic acidosis. Based on the information provided, what is acidosis, and what is the likely effect of the veterinarian's injection? Acidosis means that your dog's blood pH has ______ from its normal level, and an injection of _____ is required to reverse the condition.

A) dropped, water
B) increased, water
C) decreased, buffering solution
D) increased, buffering solution

Question 6

As you and a friend are entering a chemistry laboratory at your university, you see a sign that states: DANGER-RADIOACTIVE ISOTOPES IN USE. Your friend is an accounting major and has not had any science courses yet. She asks you what a radioactive isotope is and you respond correctly with:

A) Radioactive isotopes are atoms that are unstable and as a result emit energy in a process called radioactive decay.
B) Radioactive isotopes are atoms that are stable and as a result emit energy in a process called radioactive decay.
C) Radioactive isotopes are atoms that are stable and as a result only emit energy if they are exposed to higher temperatures.
D) Radioactive isotopes are atoms that are unstable but unless actively disturbed by some chemical process will remain intact and pose no problems.

Question 7

Capillary action is one of the forces that aids water's upward movement in plants. The narrower the diameter of the tube, the farther the water column will rise. Capillary action is a result of water molecules:

A) having an adhesive force, which allows them to attach to the vessel walls.
B) being associated with hydrophobic molecules, which can result in upward movement.
C) producing sufficient surface tension to overcome the pull of gravity.
D) having a strong cohesive force and attaching to the surrounding vessel walls.
E) storing heat and thus moving faster because of heat of vaporization.

Question 8

Membrane lipids contain long chains of H-C-H groups joined by C-C bonds. Which interaction is most likely occurring between lipids in the membrane?

A) hydrogen bonds
B) Van der Waals
C) ionic
D) covalent

Question 9

The electronic configuration of the noble gas Neon, which has an atomic number of 10, can be written as follows: 1s²2s²2p⁶. What is the electronic configuration of the noble gas Argon, which has an atomic number of 18?

A) 1s²2s⁸3p⁸
B) 1s²2s²2p⁶3s²3p⁶
C) 1s²2s⁶2p²3s⁶3p²
D) 1s²2s²3p⁶4s²5p⁶

Question 10

You identify an enzyme involved in a cellular reaction. How does the enzyme affect the reaction equilibrium between reactants and products and the time needed to reach equilibrium?

A) It alters the reaction equilibrium and shortens the time needed to reach equilibrium.
B) The reaction equilibrium is unaffected, but it shortens the time needed to reach equilibrium.
C) It alters the reaction equilibrium and lengthens the time needed to reach equilibrium.
D) The reaction equilibrium is unaffected, but it lengthens the time needed to reach equilibrium.

Question 11

Sulfur is found directly below Oxygen on the periodic table. What type of bond would you predict S-H would form?

A) Polar covalent
B) Hydrogen bond
C) Ionic
D) Non-polar covalent bond

Question 12

Salt is often used to melt ice on roads during the winter because it lowers the freezing/melting point of water. When salt dissolves in water, individual Na⁺ and Cl^- ions break away from the salt lattice and become surrounded by water molecules. Why would this cause ice to melt?

A) Hydrogen bonds are broken, and the salt ions interfere with interactions between H and O. As a result, it is more difficult for water molecules to bond and form ice.
B) Hydrogen bonds are formed, and the salt ions bond with O. As a result, it is more difficulty for water molecules to bond and form ice.
C) Hydrogen bonds are broken, and the salt ions bond with O and H respectively. As a result, it is more difficult for water molecules to bond and form ice.

Question 13

The common basilisk lizard will run across water on its hind legs in an erect position when startled by predators. This lizard has large feet and flaps of skin along its toes. What properties of water allow this lizard to walk on water?

A) Hydrogen bonds absorb heat when they break and release heat when they form. This helps to minimize temperature changes.
B) Polar molecules are attracted to ions and polar compounds, making these compounds soluble.
C) Hydrogen bonds hold water molecules together; many hydrogen bonds must be broken for water to evaporate.
D) The surface tension created by hydrogen bonds is greater than the weight of the lizard initially.

Question 14

Cl has 7 electrons in its outer shell and K has 1 electron in its outer shell. How is the bond in Cl₂ different from the bond in KCl?

A) Cl₂ is covalent and KCl is ionic.
B) Cl₂ and KCl are both ionic.
C) Cl₂ is ionic and KCl is covalent.

Question 15

According to most car mechanics, plain water is the best coolant to use in an engine provided the engine is not being exposed to freezing temperatures. If the car is subject to freezing temperatures then a mixture of water and ethylene glycol (antifreeze) is recommended but it does not cool as efficiently as plain water. Why would ethylene glycol reduce the cooling efficiency of water?

A) Hydrogen bonds in water allow high levels of heat absorption and a large increase in temperature.
B) Ethylene glycol has a higher heat capacity than water.
C) Ethylene glycol has a lower heat capacity than water.
D) Ethylene glycol raises the freezing point of water.