Question 21

What is the fundamental difference between covalent and ionicbonding?

In a covalent bond, the partners share a pair of electrons; inan ionic bond, one partner accepts electrons from the other.

Covalent bonds form between atoms of the same element; ionicbonds form between atoms of different elements.

Covalent bonding involves only the outermost electron shell;ionic bonding also involves the next electron shell inside theoutermost shell.

In covalent bonding, both partners end up with filled outerelectron shells; in ionic bonding, one partner does and the otherdoes not.

Question 22

Which of the following statements regarding the oxygen atom of awater molecule is true?

Oxygen attracts electrons less strongly than the hydrogenatoms.

Oxygen is more positively charged than the hydrogen atoms.

Oxygen is attracted to the negatively charged atoms of othermolecules.

Oxygen is more electronegative than the hydrogen atoms.

Question 23

In a water molecule, hydrogen and oxygen are held together by a________ bond.

nonpolar covalent

hydrogen

polar covalent

double covalent

Question 24

The hydrogen atoms of a water molecule are bonded to the oxygenatom by ________ bonds, whereas neighboring water molecules areheld together by ________ bonds.

polar covalent; ionic

ionic; covalent

polar covalent; hydrogen

hydrogen; polar covalent

Question 25

Which of the following statements regarding chemical reactionsis false?

Some chemical reactions create electrons; others destroythem.

The reactants contain the same number of atoms as theproducts.

Chemical reactions involve the making and breaking of chemicalbonds.

Although the atoms of a reaction's reactants and products areidentical to each other, their molecular formulas differ.

Question 26

The tendency of water molecules to stick together is referred toas

adhesion.

cohesion.

polarity.

transpiration.

Question 27

As ice melts

water molecules become less tightly packed.

the water becomes less dense.

heat is released.

hydrogen bonds are broken.

Question 28

A solution with a pH of 7 is

weakly acidic.

weakly basic.

strongly acidic.

neutral.

Question 29

Compared to a solution of pH 3, a solution of pH 1 is

10 times more basic.

10 times more acidic.

100 times more acidic.

100 times more basic.

Question 30

Which of the following statements about pH is true?

An increase in hydrogen ion concentration means a decrease inpH scale units.

A single unit change on the pH scale is equivalent to a 1%change in hydrogen ion concentration.

Basic pH levels are less than 7.

The pH scale is a measure of oxygen ion concentration.