Question 1

Which of the following statements best explains why water is considered a 'universal solvent' in biological systems?

Accepted Answer

Water molecules are polar, allowing them to surround and separate many ionic and polar substances.

Question 2

A neutral atom of sodium (Na) has an atomic number of 11 and an atomic mass of 23. How many neutrons does it have?

Accepted Answer

12

Question 3

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

Accepted Answer

A molecule is a group of atoms held together by covalent bonds, while a compound consists of two or more different elements chemically bonded.

Question 4

Which property of water is most directly responsible for the ability of plants to transport water from their roots to their leaves through capillary action?

Accepted Answer

Cohesion and adhesion

Question 5

A patient is given a solution with a pH of 3.0. Which of the following best describes this solution?

Accepted Answer

It contains more H+ ions than OH- ions and is acidic.

Question 6

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

Accepted Answer

Hydrogen bonds in ice create a lattice that makes it less dense than liquid water.

Question 7

Which of the following is true about isotopes of an element?

Accepted Answer

They have the same number of protons but different numbers of neutrons.

Question 8

A chemical equation is written as: 2H2 + O2 → 2H2O. What does the coefficient '2' in front of H2O indicate?

Accepted Answer

Two molecules of water are produced in the reaction.

Question 9

Which of the following best describes a cation?

Accepted Answer

An atom that has lost electrons and is positively charged.

Question 10

Which of the following is a correct electron configuration for a neutral atom with 10 electrons?

Accepted Answer

2 in the first level, 8 in the second level

Question 11

Which of the following best explains why table salt (NaCl) dissolves easily in water?

Accepted Answer

Water's polarity allows it to surround and separate Na+ and Cl- ions.

Question 12

Which of the following best describes a polar covalent bond?

Accepted Answer

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

Question 13

A solution is made by dissolving 10 grams of sugar in 100 mL of water. In this solution, which is the solute and which is the solvent?

Accepted Answer

Sugar is the solute; water is the solvent.

Question 14

Which of the following best describes the role of hydrogen bonds in biological molecules?

Accepted Answer

They are weak attractions that help stabilize the structure of large molecules like proteins and DNA.

Question 15

A sample of carbon contains 75% carbon-12 (atomic mass 12) and 25% carbon-13 (atomic mass 13). What is the average atomic mass of this sample?

Accepted Answer

12.25

Question 16

Which of the following best explains why living organisms are primarily composed of carbon, hydrogen, nitrogen, and oxygen?

Accepted Answer

These elements are capable of forming a wide variety of stable covalent bonds necessary for complex biological molecules.

Question 17

Which of the following statements about subatomic particles is correct?

Accepted Answer

Electrons are much lighter than protons and orbit the nucleus.

Question 18

A student is asked to balance the following chemical equation: __H2 + __O2 → __H2O. What are the correct coefficients to balance this equation?

Accepted Answer

2, 1, 2

Question 19

Which of the following best describes the octet rule as it applies to atoms in chemical bonding?

Accepted Answer

Atoms are stable when their outermost energy level contains 8 electrons.

Question 20

Which of the following is an example of an anion?

Accepted Answer

Cl-

Basic Chemistry Study Notes: Atoms, Elements, Bonds, Water, and Chemical Equations

Study Guide - Practice Questions

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