Comprehensive Problem Sets for BIO 111: Understanding Biological Systems and Chemistry

A 0.50 L (500 ml) sample of seawater contains 74.7 g of NaCl, which has a molecular weight of 58.44 g/mol. What is the molar concentration of the NaCl in the seawater?

2.56

An aqueous 5.3 M solution of hydrochloric acid is prepared with a total volume of 0.64 L (640 ml). The molecular weight of hydrochloric acid is 36.46 g/mol. How much hydrochloric acid (in grams) is needed for the solution?

123.67

How much NaCl would you need to make a 0.2 L (200 ml) of a 0.3 molar solution? NaCl has a molecular weight of 58.44 g.

3.51

If the H+ ion concentration of a household item is 10-3, how many OH- ions does it have?

10-11

11

10-13

10-3

10-11

The pH of an item is 12. Is this acidic or basic and how many H+ ions does it have?

Acidic 10-2

Cannot determine with this information

Acidic 10-12

Basic 10-12

Basic 10-2

Basic 10^-12

Most of the enzymes in our bodies function at or very close to neutral (pH ~ 7.0). There are a few exceptions. Your stomach is one of these exceptions. The enzymes in your stomach have ["More", "Equal", "Less"] H+ ions and ["Equal", "Less", "More"] OH- ions than the enzymes found in your blood?

more, less

Capsaicin is an active component of chili peppers, which are plants belonging to the genus Capsicum. It is a chemical irritant for mammals, including us, and produces a sensation of burning in any tissue with which it comes into contact. What is the molecular weight of capsicin (g/mol)? Enter a whole number (no decimal places, no units!).

C18H27NO3

305

What type of covalent bonds exist in methane?

Ionic

Polar

Non polar

Hydrogen

non polar

Using the pH scale below, compare the can of soda to the glass of milk. What is the difference between these two beverage's pH readings?

The soda has 1000x more H+ ions than the milk.

If heavy exercise produces lots of CO2 in the body, will the blood become more acidic or more basic?

Neither

More basic

More acidic

Can't determine

More Acidic

How many covalent bonds can a Carbon atom form?

4 , its how many are in the outer shell

Carbon-14 decays to nitrogen-14 with a half-life of approximately 5700 years. You find and measure a fossil sample composed of 12.5% Carbon-14 and 87.5% Nitrogen-14, approximately how old is your sample?

Hint: At time 0 your organism was 100% Carbon-14 and 0% Nitrogen-14.

17,100

Which functional groups that we talked about are NOT present in nucleotides, like the one depicted below?

Hydroxyl groups

Amino group

Carboxyl groups

Phosphate groups

carboxyl groups

Which of the following is NOT a compound?

C6H12O6

H2O

NaCl

O2

None of these

HCl

O2

Which of the following is NOT a molecule?

None of these

O

NaCl

C6H12O6

H2O

O2

O

Tantalum is a chemical element with the symbol Ta and atomic number 73 and atomic mass ~181. Its main use today is in tantalum capacitors in electronic equipment such as cell phones, DVD players, video game systems, and computers. How many protons, neutrons, and electrons does it have, respectively, in this most abundant form?

Insufficient information has been given to answer this question.

181, 73, 108

108, 73, 108

73, 108, 73

73, 181, 73

73, 108, 73

Which series of elements below are ordered from high to low electronegativity?

Ne, F, Cl, As, Ba

F, Cl, As, Ba, Ne

Ne, Ba, As, Cl, F

F, As, Cl, Ne, Ba

Ba, As, Cl, F, Ne

F, Cl, As, Ba, Ne

Which of these is NOT an essential element that makes up living matter?

All of these are essential elements

Hydrogen

Carbon

Nitrogen

Oxygen

Calcium

Iron

All of these are essential elements

Which statement about water's polarity is TRUE?

Water's polarity causes other polar molecules to be hydrophilic.

All are false

Water molecules can form up to 4 hydrogen bonds with other water molecules.

Water's polarity makes it a versatile solvent.

All are true

All are true

Biological fluids regulate pH values using solutions that can resist changes in pH called __________. This is achieved by these solutions accepting _________ when pH is low and donating _________ when pH is high.

None of the above

Buffers, OH- ions, H+ ions

Buffers, H+ ions, H+ ions

Acids, OH- ions, H+ ions

Buffers, H+ ions, H+ ions

What is the [OH-] in a solution with a pH of 13?

10-13

Cannot determine with this information

10-1

101

1013

10-1

What is the valency of Sulfur?

1

6

8

2

2, its how many are needed to complete outer shell

Which statement about enantiomers is FALSE?

All enantiomer forms have the same chemical formula.

All statements are true for enantiomers.

Their multiple forms are mirror images.

Their placement of atoms differ by having an asymmetric carbon.

They differ in the arrangement of their covalent bonds

They differ in the arrangement of their covalent bonds

An atom with 8 electrons in its outer shell tends to

bond to itself.

be a cation in aqueous solution.

bond to hydrogen in aqueous solution.

be chemically inert.

be an anion in aqueous solution.

be chemically inert.