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tEST 1

Each water molecule is joined to _____ other water molecules by ____ bonds.

four, hydrogen

The unequal sharing of electrons within a water molecule makes the water molecule _____

polar

The tendency of an atom to pull electrons toward itself is referred to as its _____.

electronegativity

In this molecule, what type of bond is found between the oxygen and hydrogens?

Polar Covalent

Why isn't this insect drowning?

surface tension

A(n) ___ is a chemical bond resulting from the attraction between atoms that have acquire a charge due to losing or gaining one or more electrons

ionic bond

A(n)_____is a chemical bond in which two atoms share one or more pairs of valence electrons

covalent bond

A(n)____is a weak chemical bond that is formed when the partially positive hydrogen atom of a polar covalent bond in one molecule is attracted to the partially negative atom of a polar covalent bond in another molecule.

Hydrogen bond

Which statements about hydrogen bonding in water are true?

The hydrogen atoms of a water molecule have a partial positive charge.
The hydrogen atom of one water molecule is attracted to the oxygen atom of a different water molecule.
The oxygen atom of a water molecule has a partial negative charge.

The oxygen atom of a water molecule is more electronegative than a hydrogen atom.

is a mesure of how difficult is to stretch or break the surface of a liquid

surface tension

is an attraction between different kinds of molecules

Adhension

is an attraction between like molecules

Cohesion

Adhesion

-Water molecules cling to plant cell walls
-Water molecules cling to the side of a beaker.

Cohesion

-Water molecules are attracted to each other.
-A drop of water spilled on a table forms a drop on the table, rather than spreading out over the surface.

Surface tension

-A water strider runs across a pond without breaking the surface.
-A sewing needle floats when it is placed gently on top of water in a bucket.

Substance with a high specific heat

-Requires more heat to change the temperature of the substance.
-More resistant to temperature change.
-Most likely to exhibit hydrogen bonding.

Substance with a low specific heat

-requires less heat to change the temperature of the substance.
-less resistant to temperature change
-least likely to exhibit hydrogen bonding.

The table shown here lists the specific heat of several substances.
Substance Specific heat

water 4.18
ethyl alcohol 2.44
benzene 1.80
sulfuric acid 1.40
Based on the information in the table, which of the following statements are true?

-Sulfuric acid is less resistant to temperature change than water
-More heat is required to raise the temperature of 1 g of water 1 than to raise the temperature of 1 g of ethyl alcohol 1 .
-Water has a high specific heat due to the hydrogen bonding between water molecules.
- Benzene is more resistant to temperature change than sulfuric acid.

What process is illustrated by this animation?

Evaporation

Which term describes the degree to which an element attracts electrons?

Electronegativity

Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?

Anion and cation

Which of the following statements is true of the bonds in a water molecule?

Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.

Which of the following statements about the atoms in a water molecule is true?

The oxygen atom in a water molecule has a partial negative charge.

Which modeling method only gives information about the number and identity of atoms in a molecule?

Molecular Formula

Which of the following statements most accurately describes the phases of water?

The entropy of water is higher than the entropy of ice.

Why does water require so much energy to change its phase?

WATER has a large number of hydrogen bonds

Which statement must be mentioned in explaining why amphipathic molecules line up at a water surface?

Polar groups attract one another.

Dissolving is best described as

a mingling of molecules and/or ions.

Water is a source of ______________ for chemical reactions in cells.

(a) hydrogen atoms
(b) oxygen atoms
(c) energy
Both (a) and (b)
(a), (b), and (c).

Both (a) and (b)
[ hydrogen atoms, oxygen atoms]

Water has surface tension because ...

hydrogen bonds between surface water molecules resist being stretched

Which of the following helps most to explain why water has a high specific heat?

A water molecule can make 4 hydrogen bonds.

Though you add heat, the temperature of boiling water remains constant because ...

it takes energy to break hydrogen bonds.

Why doesn't oil mix with water?

Polar molecules attract one another.

In a neutral solution the concentration of _____

hydrogen ions is equal to the concentration of hydroxide ions

Which of these is the correct equation for the dissociation of water?

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

What is the charge on a hydronium ion?

1+

What is the charge on a hydroxide ion?

1-

About _____ molecules in a glass of water are dissociated.

1 in 500,000,000

Which answer is a true statement about pH values?
Stomach juice has a high pH.
pH is important in life mainly because it affects the cohesion of water.
A high pH corresponds to a high H+ concentration.
Pure water has a pH of 0.
None of the above.

None of the above

What conditions must be met in order for an aqueous solution to be called "neutral"?

The concentrations of hydronium and hydroxide ions are equal.

Factory smoke has led to acid rain that lowered the pH of a lake to 5.0. What is the H+ concentration in the lake?

10- 5 M

Your tank of swamp fish needs a pH of 5, and the pH is 7 at present. What should you do to the H+ concentration?

Raise it to 100 times its present value

In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is

10-5 M

Your tank of alkali fish needs a pH of 8, and the pH is 6 at present. What should you do to the H+ concentration?

Reduce it to 1/100 of its present value.

Which of the following is a correct match of cell type with structure?

muscle cell ... has proteins that slide back and forth

Suppose that Zonosemata flies whose own wings had been clipped and reattached were attacked more frequently than untreated Zonosemata flies. How would this result affect the reliability of the other experimental results?

All results for the experimental groups involving wing surgery would be invalid

What results from the Zonosemata experiment support the sub-hypothesis that wing waving alone reduces predation by jumping spiders?

Zonosemata flies with housefly wings are attacked less frequently.

In Pasteur's experiment to test the hypothesis of spontaneous generation, why did he boil the broth in both flasks?

To kill any existing organisms in the broth

Which of the following variables did Pasteur change in his experiment to test the hypothesis of spontaneous generation?

The shape of the flask

Which of the following statements is true of a hypothesis?

A hypothesis can be supported or rejected through experimentation.

Which of the following statements could not be supported or rejected by a scientific experiment?

The first living cell on Earth came from outer space

In an experiment, investigators try to control all of the variables except one—the one that tests the hypothesis. Which of the following reasons is the primary rationale for controlling variables in an experiment?

To eliminate alternative explanations for the results of an experiment

Which of the following statements is not true of scientific experiments?

They must occur under carefully controlled conditions found in a laboratory.

What are the two main types of cells?

prokaryotes and eukaryotes

Which of these is an organ system?

digestive

An organ, such as the liver, is composed of _____.

tissues

Between 1966 and 1995, what has been the approximate decrease in stream flow rates in Monteverde?

0.8 m3/sec

Stream flow rates have apparently been decreasing worldwide since 1966.

Cannot tell from graph

It would have been reasonable to place stream flow on the X-axis instead of year.

False

Since the points don't form a straight line, it would have been better to draw this as a scatter plot.

False

Even though they live in the same location, these two species probably experience minimal competition for food.

True

The sooty tern consumes more fish than the blue-grey noddy tern.

Cannot tell from the graph

For the sooty tern, there is a steady decrease in the percent of diet as fish length decreases from 6 cm to 0 cm.

false

For what sizes of fish is there the least amount of overlap in the diets of these two tern species?

greater than 6 cm

For the graph in Step 7 showing fish body lengths and the percentage of tern diets that they comprise, which statement best summarizes the trend shown in the graph?

The blue-grey noddy's diet is composed primarily of smaller fish and the sooty tern's diet is composed mostly of moderate sized fish.

Greater abundance of tree and bush stems results in higher birth rates for snowshoe hares.

Cannot tell from graph

Increasing density of tree and bush stems has a positive effect on snowshoe hare abundance.

True

As stem density increases from about 35,000 stems to about 55,000 stems per hectare, what is the increase in snowshoe hare density?

1 hare per hectare

For the graph of data on stem density and snowshoe hare density in Step 6, which statement best summarizes the trend shown in the graph?

The density of hares increases as the density of stems increases.

hat should you do next?

Perform experiments to test your hypothesis.

Which of the following experiments would best test your hypothesis?

Find other people born in the same week and ask them what their favorite type of movie is.

What should you do next?

Refine your hypothesis.

In eukaryotic cells DNA has the appearance of a _____.

Double helix

DNA is composed of building blocks called

nucleotides

Which statement helps most to explain why life is based on carbon compounds?

C-C bonds are as strong as C-O bonds.

L-dopa is used to treat

Parkinson's disease

What kind of effect does R-dopa have on Parkinson's disease?

None

Enantiomers are molecules that

are mirror images

Geometric isomers are molecules that _____.

differ in the arrangement of their atoms about a double bond

Alcohol (OH)

is highly polar and may act as a weak acid

Carboxylic acid (H-O-C=O)

acts as an acid (DONATES IONS)

aldehyde (O=C)/ Carbonyl group

may be a structural isomer of a ketone

Thiol (S-H)

forms disulfide bonds
sulfhydryl group

Amine N-H2

acts as a base

Organic Phospahte P03

CONTRIBUTES NEGATIVE CHARGE
COMPONENT OF ATP

Which of the following statements about neutrons is false?

The neutron is positively charged.

Which of the following statements about protons is false?

The proton is found outside the nucleus of an atom

Which of the following statements about electrons is false?

The electron is electrically neutral.

Proton

Symbol: P
Charge :1+

Neutron

Symbol: n,
Charge: 0

Electron

Symbol: e
Charge: 1-

mass of ~1amu

neutron, proton

mass of ~1/2000 amu

electron

What is the mass number of an ion with 105 electrons, 157 neutrons, and a +1 charge?

263 ( add them)

The innermost electron shell of an atom can hold up to _____ electrons.

2

Which of these relationships is true of an uncharged atom?

The number of protons is equal to the number of electrons.

What determines the types of chemical reactions that an atom participates in?

the number of electrons in the outermost electron shell

What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?

6

Which of these refers to atoms with the same atomic number but different atomic masses?

These atoms are isotopes

Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?

10

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

5

A(n) _____ refers to two or more atoms held together by covalent bonds.

molecule

What name is given to the bond between water molecules?

hydrogen

Atoms with the same number of protons but with different electrical charges _____.

are different ions

In salt, what is the nature of the bond between sodium and chlorine?

ionic

An ionic bond involves _____.

an attraction between ions of opposite charges

What type of bond joins the carbon atom to each of the hydrogen atoms?

single (nonpolar) covalent

A water sample from a creek contained a single-celled organism that had both a cell membrane and a nucleus. What is its most likely classification?

Protista

The main source of energy for producers in an ecosystem is

Light energy

Often a metabolic pathway is regulated by the production of the end product, such that as the end product accumulates, the pathway is turned off. This is an example of

Negative Feedback

Which of the following are not considered "living", and cannot perform all the activities required for life?

organelle - for example, a chloroplast

Prokaryotic and eukaryotic cells have which of the following features in common?

a plasma membrane

Which of the following sequences represents the hierarchy of biological organization from the least to the most complex level?

molecule, cell, organ system, population, ecosystem, biosphere

Prokaryotes are classified as belonging to two different domains. What are the domains?

...

Two species that belong to the same class must also belong to the same

...

Which of the following types of cells do not utilize deoxyribonucleic acid (DNA) as their genetic material?

...

Which of the following statements concerning prokaryotic and eukaryotic cells is not correct?

...

Which of the following statements is false?

The neutrons and electrons present in the nucleus of an atom are almost identical in mass; each has a mass of about 1 dalton.

Each element is unique and different from other elements because of the number of protons in the nuclei of its atoms. Which of the following indicates the number of protons in an atom's nucleus?

atomic number

The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (6C)?

14silicon

How many electrons does an atom of sulfur have in its valence shell?

6

Which of the following best describes the relationship between the depicted atoms?

They are both isotopes of phosphorus.

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that

an electron may move to an electron shell farther out from the nucleus.

What results from an unequal sharing of electrons between atoms?

a polar covalent bond

Which of the following is not considered to be a weak molecular interaction?

a covalent bond

What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons?

31 daltons

The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?

The nitrogen atom has a mass number of 14 and an atomic number of approximately 7 daltons.

Natural selection tends to act at which of the following levels

population

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability dissolve substances that have charges or partial charges are

both caused by water's partial charges

In the term trace element, the adjective trace means that

the element is required in very small amounts.

For most atoms, a stable configuration of electrons is attained when the atom

has eight electrons in its outermost shell

Which of the following is an attribute of living things?

they must be able to evolve and adapt

The energy used by most organisms for metabolism and growth ultimately comes from

the sun

Phosphorus-32 radiactive has___ than phosphorus 35

3 fewer neutrons

Measurements show that the PH of a particular lake is 4.0 What is the hydrogen ion concentration of the lake?

10-4M

Ethanol, propanol and methanol are three simple alcohols. They can be grouped together because they____

all share the same functional group: Hydroxyl

WHich of these is a trace element

copper

What are the 4 most abundant elements found in living systems?

H,O,N,C

Ionic Bonds form as a result of

attraction between ions that have opposite charges

There are ___ naturally occurring elements

92

What do cohesion, surface tension, and adhesion have in common with reference to water?

all are properties related to hydrogen bonding

Which action could produce a carbonyl group?

the replacement of the -OH of a carboxyl group with hydrogen

Which of the following is the fundamental unit of structure and function in living organisms?

cell

A molecule that has all nonpolar covalent bonds would be

hydrophobic

A hydrogen bond

is a weak chemical bond

Isotopes of an element will always differ in

atomic mass

The first organic molecule to be synthesized from inorganic substances that could be prepared directly from inorganic substances was

acetic acid

The bonds that are broken when water vaporizes are

hydrogen bonds between water molecules

A controlled experiment is one that

test experimental and control groups in parallel

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