Which of the following trace elements is commonly added to table salt to prevent the formation of goiters?
When full, the innermost electron shell of argon contains ___ electrons, and the outermost shell contains ___ electrons.
2 . . . 8
Water molecules stick to other water molecules because
hydrogen bonds from between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.
_______ are weak bonds that are not strong enough to hold atoms together to from molecules but are strong enough to from bonds within and around large molecules.
The hydrogen bonds shown in this figure are each
between an oxygen and a hydrogen atom of different water molecules.
Medicines are often administered in pill from. In many cases, the active ingredient of the pill (the drug) is joined to another substance by ______. This forms a(n) _______, which is stable in the dry environment of a pill bottle but dissociates under the wet conditions of the digestive system to release the drug to the body.
ionic bonds . . . salt
Which of the following statements regarding the oxygen atom of a water molecule is true?
Oxygen is more electronegative than the hydrogen atoms
donates H+ ions when conditions become too basic and accepts H+ ions when conditions become too acidic.
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.
Which of the following trace elements may be added to bottle water in an effort to prevent tooth decay?
What change is occurring in this figure? (Check page C-3)
Chlorine is filling its third electron shell.
An unchanged atom of boron has an atomic number of 5 an atomic mass of 11. How many electrons does boron have?
What phrase best describes the connection between the ants' use of formic acid and the theme of Chapter 2?
Chemicals are part of the hierarchical structure of life.
If you were able to chemically analyze your stomach fluids 30 minutes after taking two tablets, you would find (Check page C-4)
fewer hydrogen ions.
If you could check the pH of the recommended tablets, you would expect it to be (Check page C-4)
higher than 7.
The hydrogen atoms of a water molecules are bonded to the oxygen atom by _____ bonds, whereas neighboring water molecules are held together by _____ bonds.
polar covalent . . . hydrogen
A pharmaceutical company hires a chemist to analyze the purity of the water being used in its drug preparations. If the water is pure, the chemist would expect to find
H2O molecules, H+ ions, and OH- ions
What happens to an atom if the electrons in the outer shell are altered?
The properties of the atom will change.
Which of the following statements best describes a compound?
A compound contains two or more different elements in a fixed ratio.
Which of the following will contain more heat but has a lower temperature?
an Olympic-sized heated indoor swimming pool
Which of the following would be considered an effective way to decrease the production of acid precipitation?
Whenever possible, walk or ride a bicycle instead of driving a car.
Which of the following statements about acid precipitation is false?
Acid precipitation has little or no effect on soil chemistry.
Which of the following statements regarding chemical reactions is false?
Some chemical reactions create electrons; others destroy them.
The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?
Typically, nitrogen atoms are composed of electron, protons, and neutrons. An isotope of nitrogen could
have more (than?) neutrons
Which of the following statements about water is false?
The hydrogen bonds in ice are less stable that the hydrogen bonds in liquid water.
In the equation 2 H2+O2 = 2 H2O, the H2 molecules are ______ and the H2O molecules are ______.
reactants . . . products
Household ammonia has a pH of 12; household bleach has a pH of 13. Which of the following statements about them is true?
The ammonia has 10 times as many H+ ions as the bleach.
Which of the following best describes the atomic number of an atom?
The number of protons in the atom.
Which of the following statements about radioactive isotopes is true?
The energy emitted by radioactive isotopes can break chemical bonds and cause molecular damage in cells.
The emission of ____ and ____ are primarily responsible for acid precipitation.
nitrogen oxides . . . sulfer oxides
What is the fundamental difference between covalent and ionic bonding?
In a covalent bond, the partners share a pair of electrons; in an ionic bond, one partner accepts electrons from the other.