Question 1

What unique feature of water is highlighted in this photo?

Accepted Answer

The answer of What unique feature of water is highlighted...

Question 2

Which of the following is FALSE?

Accepted Answer

Solid water (ice) is less dense than liquid water, which is why ice floats on water. This is due to the hydrogen bonds in ice that form a crystalline structure, making it less dense than its liquid form.

Question 3

A ________ is the substance used to dissolve materials.

Accepted Answer

A solvent is the substance in which the solute dissolves to form a solution.

Question 4

An aqueous solution ________. (Select all that apply)

Accepted Answer

The answer of An aqueous solution ________. (Select all that...

Question 5

The molecular weight of glucose is 181.18 g/mol. To make 250 ml of a 0.25 M glucose solution, you would dissolve ________ g of glucose in 250 ml of water.

Accepted Answer

To make a 0.25 M solution, you need 0.25 moles of glucose per liter. Since you're making 250 ml (0.25 L), you need 0.25 moles/L * 0.25 L = 0.0625 moles of glucose. The molecular weight of glucose is 181.18 g/mol, so the mass of glucose needed is 0.0625 moles * 181.18 g/mol = 11.32 g.

Question 6

Acids ________. (Select all that apply)

Accepted Answer

Acids have a pH value below 7, indicating their acidic nature. This is a fundamental property of acids, distinguishing them from bases, which have a pH above 7.

Question 7

Acid rain is a serious environmental problem. A sample of rainwater collected in the Adirondack Mountains had an H⁺ concentration of 10^-4 mol/L. The pH of this sample was ________.

Accepted Answer

The concentration of H+ ions is given as 10^-4 mol/L. The pH is calculated as the negative logarithm (base 10) of the H+ ion concentration. Therefore, pH = -log(10^-4) = 4.

Question 8

If the pH of a solution is increased from pH 5 to pH 7, it means that the concentration of H⁺ is ________ than it was at pH 5.

Accepted Answer

The pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value. Increasing pH from 5 to 7 means the solution is becoming less acidic, thus the concentration of H+ ions is decreasing. For each pH unit increase, the H+ concentration decreases by a factor of 10. Therefore, moving from pH 5 to pH 7 (a change of 2 pH units) decreases the H+ concentration by 10^2, or 100 times.

Question 9

To minimize the pH change when an acid or base is added to a solution, a ________ is needed.

Accepted Answer

A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid.

Question 10

Which of the following represent ways to increase the molecular diversity of organic molecules? (Select all that apply)

Accepted Answer

Varying the length of the carbon skeleton, the presence of multiple bonds in the carbon skeleton, branching of the carbon skeleton, and substitution of functional groups for a hydrogen are all ways to increase the molecular diversity of organic molecules.

Question 11

Which functional group acts as an acid by donating a hydrogen ion to the solution?

Accepted Answer

Carboxyl groups (-COOH) can release a hydrogen ion (H+) into the solution, acting as an acid.

Question 12

Identify this functional group.

Accepted Answer

The answer of Identify this functional group.

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Question 13

How many covalent bonds can be formed by one carbon atom?

Accepted Answer

Carbon has four electrons in its outer shell, allowing it to form four covalent bonds with other atoms.

Question 14

Glucose and fructose represent ________ isomers. (Select all that apply)

Accepted Answer

The answer of Glucose and fructose represent ________ isomers. (Select...

Question 15

The figure below illustrates ________ isomers. (Select all that apply)

Accepted Answer

The answer of The figure below illustrates ________ isomers. (Select...

Question 16

What is the chemical mechanism by which cells degrade polymers into monomers?

Accepted Answer

Hydrolysis is the chemical process by which cells break down polymers into monomers by adding water, effectively splitting the polymer bonds.

Question 17

What process does a cell use to recycle monomers?

Accepted Answer

Hydrolysis is the process through which cells break down polymers into monomers by adding water, effectively recycling the monomers for further use.

Quiz 2: An Introduction to the Chemical Basis of Life