Question 1

Which of the following statements best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice form a crystalline lattice that spaces molecules farther apart, making ice less dense than liquid water.

Question 2

A neutral atom of sodium (Na) has 11 protons. How many electrons does it have?

Accepted Answer

11

Question 3

Which property of water allows it to move up through the vessels of plants against gravity?

Accepted Answer

Cohesion and adhesion due to hydrogen bonding

Question 4

What is the mass number of a carbon atom with 6 protons and 8 neutrons?

Accepted Answer

$$14$$

Question 5

Which of the following best describes an ionic bond?

Accepted Answer

A bond formed by the attraction between oppositely charged ions after electron transfer.

Question 6

If a solution has a pH of 4, how many times more acidic is it than a solution with a pH of 6?

Accepted Answer

$$100$$ times

Question 7

Which of the following elements is NOT one of the six most abundant elements in the human body?

Accepted Answer

Iron

Question 8

A radioactive isotope of carbon, $$^{14}_{6}C$$, is used in medical imaging. What makes it radioactive?

Accepted Answer

Its nucleus is unstable due to an excess of neutrons.

Question 9

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, resulting in partial charges on atoms.

Question 10

What is the main reason water is considered the 'solvent of life'?

Accepted Answer

Water's polarity allows it to dissolve many charged and polar substances.

Question 11

Which of the following is a consequence of water's high specific heat capacity?

Accepted Answer

Water helps moderate temperature changes in organisms and environments.

Question 12

A buffer in blood helps maintain pH by:

Accepted Answer

Binding hydrogen ions when pH is low and releasing them when pH is high.

Question 13

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic compound?

Accepted Answer

Sodium donates an electron to chlorine, forming oppositely charged ions that attract each other.

Question 14

Which of the following is true about isotopes?

Accepted Answer

Isotopes of an element have different numbers of neutrons.

Question 15

Which of the following chemical reactions is balanced?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 16

Which of the following best describes the role of hydrogen bonds in water?

Accepted Answer

They are weak bonds that form between the partial positive charge of hydrogen and the partial negative charge of oxygen in neighboring molecules.

Question 17

A solution has a high concentration of $$OH^-$$ ions. What can you infer about its pH?

Accepted Answer

It is basic (pH \u003e 7).

Question 18

Which of the following is a real-life application of radioactive isotopes?

Accepted Answer

They are used as tracers in medical imaging to monitor biological processes.

Question 19

Which of the following best explains why water has a high surface tension?

Accepted Answer

Hydrogen bonds between water molecules create strong cohesive forces at the surface.

Question 20

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is made of atoms of the same element, while a compound is made of atoms of different elements.

The Chemical Basis of Life: Chapter 2 Study Notes

Study Guide - Practice Questions