Biology 1001 chapter2 Thinking Critcally

Atoms with the same number of protons but with different electrical charges _____. have different numbers of neutrons are different ions are different isotopes have different atomic numbers have different atomic masses

are different ions

Bloom's level: Remembering/Understanding 2.13 Your Uncle Eddie likes to put a lot of sugar in his coffee. When he does so, he is making a __________ in which the coffee is the __________ and the sugar is the __________. solution; solute; solvent solution; solvent; solute solute; solvent; solution cappuccino; solvent; solute

solution; solvent; solute

Of what substance are coral reefs mainly composed? ANSWER calcium carbonate skeletons of coral animals calcium carbonate skeletons of bony fish mainly rocks and kelp compressed carbon dioxide from the atmosphere bicarbonate skeletons of coral animals

calcium carbonate skeletons of coral animals

Bloom's level: Remembering/Understanding 2.3, 2.7 A neutral atom differs from its ionized form in the number of __________. The isotopes of an element differ in their number of __________. SHOW HINT electrons; protons neutrons; electrons neutrons; protons electrons; neutrons

electrons; neutrons

Bloom's level: Applying/Analyzing 2.14 How do bases act to reduce the concentration of hydrogen ions in a solution? SHOW HINT Bases can donate an OH- (hydroxide) ion. Through cohesion, bases can accept H+ ions from solution. by donating OH- ions or by accepting H+ ions Bases can accept an H+ (hydrogen) ion.

by donating OH- ions or by accepting H+ ions

The process whereby coral animals form their skeletons is called ________. ANSWER calcification acidification decalcification fluoridation evaporative cooling

calcification

What type of bond is joining the two hydrogen atoms? hydrophobic hydrogen covalent ionic hydrophilic

covalent

A(n) ________ forms when two atoms share electrons. covalent bond hydrogen bond ionic bond ion

covalent bond

Water has different properties from its components hydrogen and oxygen. Such properties are called _________. ANSWER emergent covalent ionic trace electronegative

emergent

Bloom's level: Applying/Analyzing 2.15 In the Biosphere 2 experiments, scientists varied the carbonate ion concentrations in a coral reef system while holding other factors (pH, temperature, and calcium ion concentration) constant. They measured the rates of calcification in the system. What was the dependent variable in these experiments? calcium ion concentration pH carbonate ion concentrations rate of calcification

rate of calcification

Little Freddie is a bored child at home on a rainy day. He stirs salt and sugar into his favorite soda. Freddie has created a solution with which of the following characteristics? ANSWER soda is the solvent: salt and sugar are solutes soda is the solvent: salt is the solute sugar is the solvent: salt and soda are solutes salt and sugar are the solvents: soda is the solute soda is the solvent: sugar is the solute

soda is the solvent: salt and sugar are solutes

Bloom's level: Remembering/Understanding 2.1 Which of the following substances is a compound? SHOW HINT two molecules of hydrogen gas (2H2) table salt (NaCl) Sodium (Na) hydrogen gas (H2)

table salt (NaCl)

Scientists have found several lines of evidence pointing to the existence of water on Mars. Which of the following have they NOT observed? ANSWER water-filled lakes or ponds ice caps at both poles soil samples containing water clay samples that probably contained water "waterlogged" molecules in streaks on surface

water-filled lakes or ponds

Bloom's level: Remembering/Understanding 2.1, 2.2 Which of the following statements is true regarding trace elements? SHOW HINT Trace elements are very rare on Earth. Trace elements rarely reach levels in the body that are too high. Trace elements improve health short-term, but are not essential for long-term survival. Excessive amounts of trace elements can damage the body.

Excessive amounts of trace elements can damage the body.

What happens when water is heated? ANSWER Hydrogen bonds are broken. Hydrogen bonds are created. Covalent bonds are broken. Covalent bonds are created. Both hydrogen and covalent bonds are broken.

Hydrogen bonds are broken.

A radioactive tracer called PIB can be used to detect beta-amyloid plaques in the brains of some people with Alzheimer's disease. This represents the medical use of radioactive isotopes to _________. ANSWER diagnose disease study metabolism localize substances treat disease study radioactivity

diagnose disease

A(n) _____ bond joins these two oxygen atoms. single covalent hydrogen quadruple covalent ionic double covalent

double covalent

A phrase that applies to covalent bonding and not other kinds of bonds is ... paired electrons .great strength. electron-sharing. charge attraction. All of the above.

electron-sharing.

Which subatomic particles are directly involved in an atom's chemical activity? ANSWER electrons protons neutrons protons and electrons protons and neutrons

electrons

You've been experiencing acid indigestion lately, and you'd like a quick fix for the problem. You do a little research on the Internet and discover that your problem is caused by excess stomach acid. In the pharmacy aisles, however, you're having a little trouble deciding what to purchase to address the problem. At the pharmacy counter, the clerk recommends that you purchase PEPCID AC or Alka-Seltzer tablets. If you were able to chemically analyze your stomach fluids 30 minutes after taking two tablets, you would find the same number of hydrogen ions. fewer hydrogen ions. that the pH in your stomach has decreased. more hydrogen ions.

fewer hydrogen ions.

Which of the following is a disease caused by an excess of a trace element and what is the element? ANSWER fluorosis: fluoride fluorosis: iodine goiter: iodine iron deficiency: iron calcification: calcium

fluorosis: fluoride

Bloom's level: Analyzing/Applying 2.14 Human urine has a pH of about 6. Milk of magnesia has a pH of about 10. Household bleach has a pH of about 12. Arrange the three substances in descending order of basicity (most basic to least basic). SHOW HINT human urine, household bleach, milk of magnesia human urine, milk of magnesia, household bleach household bleach, milk of magnesia, human urine milk of magnesia, household bleach, human urine

household bleach, milk of magnesia, human urine

Bloom's level: Remembering/Understanding 2.4 Which of the following describes the use of a radioactive tracer to diagnose a disease? SHOW HINT injecting a radioactive tracer to determine how oxygen is metabolized in the body injecting radioactive iodine to kill cancer cells in the thyroid gland injecting a tracer that binds to beta-amyloid plaques in the brain injecting a radioactive tracer

injecting a tracer that binds to beta-amyloid plaques in the brain

In salt, what is the nature of the bond between sodium and chlorine? polar covalent ionic hydrogen hydrophobic nonpolar covalent

ionic

A deficiency of _______ is the world's most common nutritional deficit. ANSWER iron iodine fluorine oxygen potassium

iron

A(n) _____ refers to two or more atoms held together by covalent bonds. isotope ion molecule shell community

molecule

In Sweden (a cold country) one year, there was sunshine from July 1-July 10, followed by several days of very cold, rainy weather. If you wanted to stay warm that year during your late-July camping trip, where was the best place to pitch your tent? Why? ANSWER near the coast: water stores heat from the sun and releases it gradually near the coast: water reflects heat and releases it quickly far from the coast: water stores heat from the sun and releases it gradually far from the coast: water reflects heat and it flows inland near the coast: water reflects heat and it flows inland

near the coast: water stores heat from the sun and releases it gradually

What information is provided by a molecule's structural formula that is not provided by its molecular formula? ANSWER number of covalent bonds and whether they are single, double, or triple number of covalent bonds number of atoms of each element in the molecule distribution of electrons three-dimensional shape of the molecule

number of covalent bonds and whether they are single, double, or triple

An atom's mass number equals which of the following? ANSWER number of protons + number of neutrons number of protons + number of electrons number of protons number of neutrons number of protons + number of neutrons + number of electrons

number of protons + number of neutrons

A hydrogen atom has one electron. How many covalent bonds can hydrogen form? four none two one

one

Bloom's level: Remembering/Understanding 2.1 Which of the following choices includes elements that each contribute at least about 10% of the human body? SHOW HINT oxygen, carbon, hydrogen, sodium oxygen, carbon, hydrogen carbon, calcium, nitrogen, oxygen oxygen, carbon, hydrogen, water

oxygen, carbon, hydrogen

Bloom's level: Applying/Analyzing 2.6 The bond between the two hydrogen atoms in an H2 molecule are __________. The bonds between two oxygen atoms in an O2 molecule are __________. SHOW HINT polar; nonpolar nonpolar; polar nonpolar; nonpolar polar; polar

polar; polar

In a covalent bond, electrons are ________. In an ionic bond, electrons are ______. Which is the stronger type of bond? ANSWER shared: transferred: covalent transferred: shared: covalent shared: transferred: ionic transferred: shared: ionic shared: shared: covalent

shared: transferred: covalent

What type of bond joins the carbon atom to each of the hydrogen atoms? ionic polar covalent hydrogen double (nonpolar) covalent single (nonpolar) covalent

single (nonpolar) covalent

Bloom's level: Applying/Analyzing 2.10. Water striders (a type of insect) can move swiftly across a pond without breaking the water's surface. This is due to their light weight and the water's __________. SHOW HINT surface tension thermal energy adhesion shallow depth

surface tension

Bloom's level: Remembering/Understanding 2.15 What, if any, is the effect on coral reefs of excess CO2, which is produced by the burning of fossil fuels? It makes the ocean more basic and benefits coral reefs. It benefits coral reefs because the ocean soaks up the atmospheric CO2, which coral animals need. It acidifies the ocean and harms coral reefs. It has little effect on coral reefs.

It acidifies the ocean and harms coral reefs.

Bloom's level: Remembering/Understanding 2.9. State the equation for photosynthesis in words. SHOW HINT Six molecules of oxygen gas combine with six molecules of water to form one molecule of glucose and six molecules of carbon dioxide gas. Six molecules of carbon dioxide gas combine with one molecule of water to form one molecule of glucose and six molecules of oxygen gas. Six molecules of carbon dioxide gas combine with six molecules of water to form one molecule of glucose and six molecules of oxygen gas. Six molecules of carbon dioxide gas combine with six molecules of water to form six molecules of glucose and six molecules of oxygen gas.

Six molecules of carbon dioxide gas combine with six molecules of water to form one molecule of glucose and six molecules of oxygen g

Which of the following is NOT a true statement regarding radioactive isotopes? ANSWER They can be used to diagnose, but not to treat, certain diseases. They are helpful in dating fossils. They can be used both to treat and to diagnose certain diseases. They result from the spontaneous decay of an atomic nucleus. They are usually more unstable than non-radioactive isotopes

They can be used to diagnose, but not to treat, certain diseases

Hydrogen and helium are the only elements in the first row of the periodic table. What characteristic(s) do they share that determines their position? ANSWER They have only one electron shell. They are both gases. Their valence shells are empty. Their valence shells are full. They have the same number of electrons in their valence shell.

They have the same number of electrons in their valence shell.

Dr. Haxton says the O-O bond is polar and the C-C bond is nonpolar. A good student would say ... Right! O is electronegative, so O2 is polar. No way. C is more electronegative than O. Yes. O attracts electrons more strongly than C. No, both bonds are highly polar. Wrong again, Ralph. Both bonds are nonpolar.

Wrong again, Ralph. Both bonds are nonpolar.

Which of the following is the best definition of a "polar" molecule? ANSWER a molecule with an unequal distribution of charges a molecule with one oxyen atom and two hydrogen atoms a water molecule a molecule whose atoms donate electrons a molecule whose atoms share electrons

a molecule with an unequal distribution of charges

What is radon? ANSWER a radioactive gas from the decay of uranium that can cause lung cancer a radioactive gas from the decay of Carbon-14 that can cause lung cancer a method of tracking submarines underwater using radio waves a radioactive tracer used in medicine to detect beta-amyloid plaques a radioactive gas from the decay of uranium that causes skin cancer

a radioactive gas from the decay of uranium that can cause lung cancer

About _____ molecules in a glass of water are dissociated. 1 in 2 1 in 1,000,000 1 in 5,000,000 1 in 500,000,000 1 in 1,000,000,000

1 in 500,000,000

What is the charge on a hydronium ion? 2- 1- 1+ 0 2+

1+

Consider the following situations: (1) a magnesium atom and two chlorine atoms join together to form a molecule of magnesium chloride; (2) water molecules interact with each other in a beaker; and (3) two carbon atoms and six hydrogen atoms join together to form ethane. Rank the strength of the bonding interactions taking place in each situation, from the weakest bonds to the strongest bonds. 3 < 2 < 1 2 < 3 < 1 2 < 1 < 3 1 < 2 < 3

2 < 1 < 3

Bloom's level: Remembering/Understanding 2.3 An isotope of carbon has 6 protons, 7 neutrons, and 6 electrons. Its atomic number is __________ and its mass number is __________. SHOW HINT 13; 6 6; 7 6; 13 6; 12

6; 13

The cells of the human body are about ____% water. Six elements together make up about 99% of the body. In addition to oxygen, carbon, and hydrogen, these are _______, _______, and ______. ANSWER 70%: nitrogen, calcium, phosphorus 70%: nitrogen, calcium, potassium 50%: nitrogen, calcium, phosphorus 50%: sodium, iron, potassium 40%: iron, potassium, chlorine

70%: nitrogen, calcium, phosphorus

Bloom's level: Appling/Analyzing 2.9 Which of the following statements about chemical reactions is NOT true? SHOW HINT There are always the same number of atoms of each element on both sides of the arrow. Reactants (on left of arrow) yield products (on right of arrow). Chemical reactions result in the rearrangement of atoms. In some chemical reactions, matter is created.

Chemical reactions result in the rearrangement of atoms.

If you want a molecule that is highly polar, look for one that contains: C-S C-H H-N O-N S-H

H-N

Which of these is the correct equation for the dissociation of water? H2O <==> H+ + OH- H+<==> H2O + H2O+ H2O + H2O <==> H3O+ + OH- H2O + OH-<==> H2O+H2O + H2O+<==> H2O + OH-

H2O + H2O <==> H3O+ + OH-

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 only H2O molecules and H+ ions. only H+ ions and OH- ions.H2O molecules, H+ ions, and OH- ions. only molecules of H2O.

H2O molecules, H+ ions, and OH- ions.

Water molecule A has two hydrogens, called HA1 and HA2. Its oxygen atom is called OA. The same naming rules apply to water molecules B, C, D, and E. How does Molecule A form its hydrogen bonds? ANSWER HA1 bonds with OB, HA2 bonds with OC, and OA bonds with HD1 and HE1. HA1 and HA2 bond with OB. HA1 bonds with OB, HA2 bonds with OC HA1 and HA2 bond with OA. HA1 bonds with OB, HA2 bonds with OC, OA bonds with HD1 and HD2.

HA1 bonds with OB, HA2 bonds with OC, and OA bonds with HD1 and HE1.

Bloom's level: Remembering/Understanding 2.6, 2.7 How are ionic bonds formed? SHOW HINT In ionic bonds, one atom gives up an electron to a second, less electronegative atom. Ionic bonds are formed when electrons are shared. In ionic bonds, one atom gives up an electron to a more electronegative second atom. Ionic bonds are formed only between isotopes.

In ionic bonds, one atom gives up an electron to a more electronegative second atom.

Which of the following is a characteristic of Carbon-14, but not of Carbon-12 or Carbon-13? ANSWER Its nucleus is unstable. Its nucleus is stable. It has 6 protons in its nucleus. It has a mass number of 12. It has 6 electrons.

Its nucleus is unstable.

Bloom's level: Applying/Analyzing 2.11 Why does sweating cool us? SHOW HINT Sweating allows the water molecules with the lowest energy to leave the body first. Sweating allows the water molecules with the highest energy to leave the body first. Sweating changes the surface tension of water. Sweating allows toxins to escape from the body.

Sweating allows the water molecules with the highest energy to leave the body first.

Which of the following are the reactants in the chemical reaction that results in 2 molecules of water (2H2O)? ANSWER 2 molecules of hydrogen gas and 1 molecule of oxygen gas 2 molecules of hydrogen gas and 2 molecules of oxygen gas 2 atoms of hydrogen gas and 1 atom of oxygen gas 2 atoms of hydrogen gas and 2 atoms of oxygen gas 1 molecule of hydrogen gas and 1 molecule of oxygen gas

2 molecules of hydrogen gas and 1 molecule of oxygen gas

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many electrons does boron have? 15 2 5 11

5

The atomic number of neutral sulfur = 16. How many electrons does a sulfur atom have in its valence shell? ANSWER 6 3 8 5 2

6

Which of the following statements regarding matter is false? All matter exists in the form of compounds. All matter is composed of elements. All matter has mass. All life is composed of matter.

All matter exists in the form of compounds

Glycolysis is the first step of cellular respiration, in which glucose is used to generate ATP to power the cell. The major chemical reaction that takes place in glycolysis (ignoring some other reactants and products) is the conversion of glucose (C6H12O6) to pyruvate (C3H4O3) and hydrogen ions (H+). Using this information, what is the correct equation for the glycolysis chemical reaction? C6H12O6 → 2 C3H4O3 + 4 H+ C6H12O6 → C3H4O3 + H+ 2 C6H12O6 → C3H4O3 + 2 H+ C6H12O6 → 2 C3H4O3 + H+

C6H12O6 → 2 C3H4O3 + 4 H+

Bloom's level: Remembering/Understanding 2.5 Which of the following atoms can form the most covalent bonds with another atom? The number of electrons in each atom's valence shell is provided. SHOW HINT H (1) O (6) C (4) N (5)

N (5)

Which answer correctly ranks the atoms in terms of decreasing electronegativity (the highest electronegativity first)? O, N, C, H O, N, H, C N, O, H, C N, O, C, H C, H, O, N

O, N, C, H

Use your knowledge of electronegativity to pick out the most polar bond in the list below. N-H O-N O-H O-C C-H

O-H

Which of the following statements regarding the oxygen atom of a water molecule is true? Oxygen attracts electrons less strongly than the hydrogen atoms. Oxygen is more positively charged than the hydrogen atoms. Oxygen is more electronegative than the hydrogen atoms. Oxygen is attracted to the negatively charged atoms of other molecules.

Oxygen is more electronegative than the hydrogen atoms.

An ionic bond involves _____. water avoidance the unequal sharing of an electron pair no atoms other than sodium and chlorine an attraction between ions of opposite charge the sharing of a single pair of electrons

an attraction between ions of opposite charge

Which of the following is dependent on the ability of water molecules to form hydrogen bonds with other molecules besides water? the ability of certain insects to walk on the surface of water the milder temperatures of coastal regions compared to inland areas the evaporative cooling of skin surfaces the universality of water as a solvent

the universality of water as a solvent

Bloom's level: Analyze--> 2.12 What is happening to the molecular bonds in water as the ice cubes in your soda melt? SHOW HINT As the ice melts, the hydrogen bonds between water molecules change so that the molecules are farther away from each other. As the ice melts, the hydrogen bonds between water molecules change so that the molecules are packed closer to each other. As the ice melts, new hydrogen bonds between water molecules begin to appear. As the ice melts, the hydrogen bonds between water molecules begin to disappear.

As the ice melts, the hydrogen bonds between water molecules change so that the molecules are packed closer to each other.

Sodium chloride (NaCl, table salt) is a compound but not a molecule. Why? ANSWER It does not contain covalent bonds. It does not contain ionic bonds. Its components are not combined in a fixed ratio. It can dissolve in water. It consists of trace elements.

It does not contain covalent bonds

Which atom in the pictured molecule will have the strongest partial positive charge? The C that's in C=O. The N atom. The H that's bound to O. The O atom that's in C=O. The C that's bound to N.

The C that's in C=O.

Household ammonia has a pH of 12; household bleach has a pH of 13. Which of the following statements about these substances is true? The ammonia has 10 times as many OH- ions as the bleach. A solution that could buffer the bleach and ammonia would remove excess OH- ions. The ammonia has 10 times as many H+ ions as the bleach. Both of these substances are strong acids.

The ammonia has 10 times as many H+ ions as the bleach.

What happens to an atom if the electrons in the outer shell are altered? The atom becomes a different element .The atom becomes radioactive. The atom loses a proton. The atom acquires different properties.

The atom acquires different properties.

The body uses atoms in different ways to accomplish different tasks. For example, one portion of the body's calcium supply strengthens bones, whereas another portion combines with proteins to stimulate blood clotting after tissue injury. Which of the following statements provides the most logical chemical explanation of calcium's ability to perform such different functions? The bone contains calcium salts, which are less reactive than the calcium ions found in the blood. The calcium in blood has a lighter atomic mass than the calcium in bone and is in a more reactive form. The calcium in blood is a more reactive form of the atom and therefore has fewer protons than the calcium in bone. There are many different isotopes of calcium, and the most reactive isotope is found in the bone.

The bone contains calcium salts, which are less reactive than the calcium ions found in the blood.

Drinking a (safe) buffering solution after eating a very acidic meal would be likely to have which of the following effects on the pH of a person's stomach contents? ANSWER The pH would increase slightly. The pH would decrease slightly. The pH would be unchanged. The pH would increase by a large amount. The pH would decrease by a large amount.

The pH would increase slightly.

Bloom's level: Remembering/Understanding 2.8 Which of the following choices lists chemical bonds from strongest to weakest? SHOW HINT hydrogen, ionic, covalent covalent, ionic, hydrogen hydrogen, covalent, ionic ionic, covalent, hydrogen

covalent, ionic, hydrogen

A radioactive isotope is an isotope that decays. has the same atomic mass but a different atomic number than the common variant of the element. is stable .has more protons than the common variant of the element.

decays.

Examine the graph. The x-axis shows increasing concentrations of carbonate ions (CO32-) in seawater, while the y-axis shows the rate of calcification of animals on coral reefs. What does this graph tell you about the relationship between the two variables? ANSWER the more carbonate ion in seawater, the higher the rate of calcification the more carbonate ion in seawater, the lower the rate of calcification There is no relationship between the amount of carbonate ion in seawater and the rate of calcification. the less carbonate ion in seawater, the higher the rate of calcification the less carbonate ion in seawater, the better for coral reefs

the more carbonate ion in seawater, the higher the rate of calcification