17 Testing Your Knowledge s. Why are biologists sointerested inchemistry a. Chemicals are the fundamental parts of all Multiple choice living things. b. Most chemicals are harmful to living things. 1. Which of the following is a trace element, re- They know little about life except the chemi- quired only in small amounts by most living cals it made from. d. you understand the dhemistry of life, you oxygen can make a lot of money. b, iron ie. Everything about life can be knowm by un- derstanding its dhemistry. d, carbon 9. Molecules are always moving, some molecules move faster than others; is a 2. An acid is a substance that their average velocity of movement. dissolves in water. b, forms covalent bonds with other substances. b, heat c. donates hydrogen ions to solutions. d. is a versatile solvent. e, removes hydrogen ions from solutions. How an atom behaves when it comes into con- 10 Which of the following holds atomstogether in tact with other atoms is determined by its a. nucleus. a. ionic bonds between atoms b. size. b. transfer of protons from one atom to another sharing of electrons between atoms d, neutrons. d. loss of neutrons by atoms e sharing of protons between atoms 4. Most of water\'s unique properties result from 11. loe floats because the fact that water molecules a. it is colder than liquid water a. are very small. its molecules are moving faster than in liq- b. tend to repel each other. uid water. extremely large. c it is more dense than liquid water. d. tend to stick together. d its hydrogen molecules bond to the water e are in constant motion. e, its water molecules are farther apart than in 5. Atoms of different phosphorus isotopes a. have different atomic numbers. b, have different numbers of neutrons. 12. Adding acid tends to of a solution. e. react differently with other atoms. a. increase the hydrogen ion concentration and d. have different numbers of electrons. raise the pH e. have different numbers of protons. b, increase the hydrogen ion concentration and lower the PH 6. An ion is formed when an atom c. decrease the hydrogen ion concentration forms a oovalent bond with another atom. and raise the pH b. gains or loses an electron. d. decrease the hydrogen ion ooncentration becomes part of a molecule. and lower the pH d. gains or loses a proton. e. cord,depending on the original acidity e, gains or loses a neutron. 7. The smallest particle of water is Essay a. an atom. 1. List the four elements meeded by living things b a crystal. in large amounts, two others needed in moder- an element. ate amounts, and two elements needed in trace d, a Solution 1. The answer is: b. Iron. Others are macro nutrient, require in higher amounts by the body. 2. The answer is: c. donates hydrogen ions to solutions. Acid is a proton donator. 3. The answer is: e. electrons. How an atom behaves when it comes in contact with other atoms is determined by its electronic configuration and hence electrons. 4. The answer is: d tend to stock togethe.

1. 17 Testing Your Knowledge s. Why are biologists sointerested inchemistry a. Chemicals are the
fundamental parts of all Multiple choice living things. b. Most chemicals are harmful to living
things. 1. Which of the following is a trace element, re- They know little about life except the
chemi- quired only in small amounts by most living cals it made from. d. you understand the
dhemistry of life, you oxygen can make a lot of money. b, iron ie. Everything about life can be
knowm by un- derstanding its dhemistry. d, carbon 9. Molecules are always moving, some
molecules move faster than others; is a 2. An acid is a substance that their average velocity of
movement. dissolves in water. b, forms covalent bonds with other substances. b, heat c. donates
hydrogen ions to solutions. d. is a versatile solvent. e, removes hydrogen ions from solutions.
How an atom behaves when it comes into con- 10 Which of the following holds atomstogether in
tact with other atoms is determined by its a. nucleus. a. ionic bonds between atoms b. size. b.
transfer of protons from one atom to another sharing of electrons between atoms d, neutrons. d.
loss of neutrons by atoms e sharing of protons between atoms 4. Most of water's unique
properties result from 11. loe floats because the fact that water molecules a. it is colder than
liquid water a. are very small. its molecules are moving faster than in liq- b. tend to repel each
other. uid water. extremely large. c it is more dense than liquid water. d. tend to stick together. d
its hydrogen molecules bond to the water e are in constant motion. e, its water molecules are
farther apart than in 5. Atoms of different phosphorus isotopes a. have different atomic numbers.
b, have different numbers of neutrons. 12. Adding acid tends to of a solution. e. react differently
with other atoms. a. increase the hydrogen ion concentration and d. have different numbers of
electrons. raise the pH e. have different numbers of protons. b, increase the hydrogen ion
concentration and lower the PH 6. An ion is formed when an atom c. decrease the hydrogen ion
concentration forms a oovalent bond with another atom. and raise the pH b. gains or loses an
electron. d. decrease the hydrogen ion ooncentration becomes part of a molecule. and lower the
pH d. gains or loses a proton. e. cord,depending on the original acidity e, gains or loses a
neutron. 7. The smallest particle of water is Essay a. an atom. 1. List the four elements meeded
by living things b a crystal. in large amounts, two others needed in moder- an element. ate
amounts, and two elements needed in trace d, a
Solution
1. The answer is: b. Iron.
Others are macro nutrient, require in higher amounts by the body.
2. The answer is: c. donates hydrogen ions to solutions.
Acid is a proton donator.
3. The answer is: e. electrons.

2. How an atom behaves when it comes in contact with other atoms is determined by its electronic
configuration and hence electrons.
4. The answer is: d tend to stock together.
Most of waters unique properties are due to the ability of water molecules to tend to stick
together.