Chemistry of Life Test

A hydrogen atom has one electron. How many covalent bonds can hydrogen form?

• one covalent bond

• four covalent bonds

• four covalent bonds

• two ionic bonds

• two isotonic bonds

What is the fundamental difference between covalent and ionic bonding?

• In a covalent bond, the partners have identical electronegativity; in an ionic bond, one of them is more electronegative

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

• In covalent bonding, both partners end up with filled outer electron shells; in ionic bonding, one partner does and the other does not.

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

  the outermost shell.

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

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

• Oxygen is more positively charged than the hydrogen atoms.

• Oxygen attracts electrons less strongly than the hydrogen atoms.

• Oxygen is more electronegative than the hydrogen atoms.

• Oxygen is electrically neutral

• Oxygen is attracted to the negatively charged atoms of other molecules.

In a water molecule, hydrogen and oxygen are held together by a(n) ________ bond.

• double covalent

• ionic

• nonpolar covalent

• hydrogen

• polar covalent

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

• hydrogen . . . ionic

• hydrogen . . . polar covalent

• polar covalent . . . hydrogen

• ionic . . . covalent

• polar covalent . . . ionic

Tags

NGSS.HS-PS2-6

________ are weak bonds that are not strong enough to hold atoms together to form molecules but are strong enough to form bonds within and around large molecules.

• Ionic bonds

• Covalent bonds

• Polar covalent bonds

• Hydrogen bonds

• Anionic bonds

Water molecules stick to other water molecules because

• water molecules are neutral, and neutral molecules are attracted to each other.

• hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.

• covalent bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.

• the hydrogen atoms of adjacent water molecules are attracted to one another.

• the oxygen atoms of adjacent water molecules are attracted to one another.

The tendency of water molecules to stick together is referred to as

• adhesion.

• polarity.

• cohesion.

• transpiration.

• evaporation.

Which of the following statements about water is false?

• Ice is less dense than liquid water.

• The hydrogen bonds in ice are less stable than the hydrogen bonds in liquid water.

• Water naturally exists in all three physical states on Earth.

• Floating ice on a pond insulates the liquid water below, slowing its rate of freezing.

• If ice sank, the oceans would eventually freeze solid.

Tags

NGSS.HS-ESS2-5

You've made a hot drink by dissolving a teaspoon of instant coffee and a teaspoon of sugar in a cup of hot water. Which of the following statements is true?

• You've just prepared an aqueous solution.

• The water is the solute portion of the drink

• The instant coffee and sugar are solvents.

• The instant coffee and sugar dissolve because they have no charged regions to repel the partial positive and partial negative regions of the water molecules.

• The coffee and sugar would not dissolve in cold water.