Deck 2: Basic Chemistry

Question 1

Both ¹⁸O and ¹⁶O are found in nature.However,¹⁶O is the most common.Therefore,

A)these are different elements.
B)oxygen atoms can have eight or 10 neutrons.
C)¹⁸O has two additional electrons in its outer shell.
D)¹⁸O is the form of oxygen that provides living cells with life.
E)only the common form of ¹⁶O can bond with hydrogen atoms to form H₂O.

Answer 1

B

Question 2

In a water molecule,

A)the oxygen atom is more electronegative than the hydrogen atoms.
B)the oxygen atom has an overall negative charge with the hydrogen atoms having an overall positive charge.
C)unequal sharing of electrons results in a polar molecule.
D)All of the choices are correct.

Answer 2

D

Question 3

A valence shell is best described as

A)the electron shell closest to the nucleus.
B)the outermost electron shell of an atom.
C)the volume of space in which electrons are most often found.
D)the original energy level of electrons in photosynthesis.

Answer 3

B

Question 4

Which is NOT true about the electrical charges of elements?

A)Protons carry a positive charge.
B)In an atom,the number of protons and neutrons must be equal.
C)An atom is neutral when the positive and negative charges balance.
D)Neutrons have no electrical charge.

Question 5

Prior to prescription medications to control stomach acid and heart burn,people consumed baking soda (sodium bicarbonate)to alleviate their symptoms.To be effective,baking soda must:

A)effectively buffer stomach acid by releasing H⁺.
B)release water and dilute the stomach acid.
C)block acid production by combining with OH^-.
D)neutralize stomach acid by combining with excess H⁺.

Question 6

The periodic table displays the following information about the element phosphorus: 15
P
30.794
Based on this information,which of the following are true statements about phosphorus? Select all that apply.

A)The atomic number of phosphorus is 30.794.
B)Phosphorus has 15 protons.
C)Phosphorus has 30.794 electrons.
D)Phosphorus has a complete valence shell.
E)Phosphorus will form chemical bonds with other elements.

Question 7

If the atomic number of chlorine is 17 and the atomic mass is 35,how many neutrons are there in the nucleus?

A)17
B)18
C)35
D)70

Question 8

The periodic table gives the following information about oxygen: 8
O
15.99
A scientific article that you are reading mentions oxygen-18.How is oxygen-18 different from the typical oxygen atom described in the periodic table? Select all that apply.

A)Oxygen-18 is an isotope.
B)Oxygen-18 has 10 additional protons.
C)Oxygen-18 has 2 additional neutrons.
D)Oxygen-18 has a full valence shell and is therefore nonreactive.
E)Oxygen-18 has more protons and fewer neutrons than a typical oxygen atom.

Question 9

What does this graph reveal about the heat of vaporization and the heat of fusion?

Question 10

What relationship can be determined from the following information: • The radioactive isotope iodine 131 has a half-life of 8.1 days and emits 0.8 MeV (milli-electronvolts)of energy.
• The radioactive isotope phosphorus 32 has a half-life of 14.3 days and emits 1.7 MeV of energy.
• The radioactive isotope phosphorus 33 has a half-life of 25.5 days and emits 0.25 MeV of energy.
• The radioactive isotope sulfur 35 has a half-life of 87.5 days and emits 0.2 MeV of energy.

A)The longer the half-life,the more energy emitted by the particles.
B)The longer the half-life,the less energy emitted by the particles.
C)Radioisotopes of the same element must emit the same amount of energy in their emissions and decay at the same rate.
D)Adjusted for time,radioisotopes emit the same amount of energy in their emissions.
E)Energy and half-life are not directly related.

Question 11

Which of the following elements would be the most reactive with other elements?

A)boron,#5
B)neon,#10
C)argon,#18
D)helium,#2

Question 12

An article in a medical journal indicates that researchers have used an isotope ³H to trace a certain metabolic process.From the symbol that is given,we know this is a hydrogen isotope with

A)three protons.
B)three neutrons.
C)three electrons.
D)one proton and two neutrons.
E)two protons and one neutron.

Question 13

If you place the corner of a paper towel into a droplet of water,the water moves into the paper towel.Which of the following would explain the movement of the water?

A)surface tension
B)cohesion
C)adhesion
D)Both cohesion and adhesion.

Question 14

To determine the age of fairly recent fossils and organic artifacts,it is possible to analyze the amounts of the isotopes ¹⁴C and ¹⁴N,because over time the ¹⁴C-which originated in the atmosphere-breaks down into ¹⁴N through a process known as beta decay.What net change occurred for this to happen?

A)The ¹⁴C lost an electron.
B)The ¹⁴C gained an electron.
C)The ¹⁴C lost a proton.
D)The ¹⁴C gained a proton.
E)The ¹⁴C gained a neutron.

Question 15

Which statement is NOT true about covalent bonds?

A)Covalent bonds form when an electron is completely lost or gained from an atom.
B)A covalent molecule contains one or more covalent bonds.
C)A single covalent bond is drawn as a line between two atoms.
D)A pair of electrons is shared between two atoms for each covalent bond.
E)Shared electrons allow an atom to complete its valence shell in a covalent molecule.

Question 16

Which of the following statements is NOT true about electron configurations?

A)If an atom has only one shell,it is complete with two electrons.
B)If an atom has two or more shells,the octet rule applies.
C)If an atom has two or more shells,the outer shell is complete with eight electrons.
D)Atoms with more than eight electrons in the outer shell react by gaining electrons.
E)Atoms with eight electrons in the outer shell are not reactive.

Question 17

Which statement is NOT true about ionic bonds?

A)One atom acts as an electron donor and another atom acts as an electron acceptor.
B)Electrons are completely lost or gained in ion formation.
C)An ion has the same number of electrons as a nonionic atom of the same element.
D)An ionic bond occurs between positive ions and negative ions.
E)A salt such as NaCl is formed by an ionic reaction.

Question 18

An atom's atomic mass is best described as the mass of

A)the protons it contains.
B)the neutrons it contains.
C)electrons in the outermost shell.
D)protons and neutrons it contains.
E)protons and electrons it contains.

Question 19

Your roommate has heartburn and you hand her a bottle of antacids.She wants you to explain how the antacids will make her feel better.What do you tell her?

A)Antacids dilute the solution,therefore lowering the pH.
B)Antacids are bases and can take up H⁺ thereby reducing the acidity of the solution.
C)Antacids are bases and by definition can take up OH^- thereby increasing the acidity of the solution.
D)Antacids contain mostly water and so they neutralize the solution.

Question 20

Which statement is NOT true about subatomic particles?

A)Protons are found in the nucleus.
B)Neutrons have no electrical charge.
C)Electrons contain much less mass than neutrons.
D)Electrons are found in orbitals around the nucleus.
E)All electrons in an atom contain the same amount of energy.

Question 21

Draw three water molecules and the hydrogen bonding that may occur between the molecules.Define hydrogen bonding and explain how and why it occurs.

Question 22

A solution with a pH of 7.0 has ________ times ________ H⁺ than a solution of pH 10.

A)30; more
B)300; less
C)1000; more
D)1000; less
E)None of these are correct.

Question 23

Which statement is NOT true about polar covalent bonds?

A)When covalent bonds are nonpolar,the electrons are shared fairly equally between the atoms.
B)Polar covalent bonds are important in the characteristics of water.
C)Electrons are shared unequally in a polar covalent bond.
D)The larger atom in a polar bond attracts the electron more strongly than the smaller atom.
E)The oxygen of a water molecule is electropositive relative to the hydrogen.

Question 24

Study the chart to determine the relationship between H⁺ concentration and pH.If you were to create a herbal remedy to decrease excess stomach acid,would you create a solution with a relatively greater or lesser number of hydrogen ions?

Question 25

The scale ranges from 1 to 15.

Question 26

The blood buffer reactions described by H₂CO₃
<--------> H⁺ + HCO₃- indicate that

A)scientists are uncertain which direction the equation flows.
B)the reaction can flow either direction depending on whether there is too much H⁺ or more H⁺ is needed.
C)any reaction in one direction causes an immediate reverse reaction.
D)chemicals can swing wildly from acidic to basic.
E)the reaction goes back and forth in an unpredictable manner.

Question 27

As a solid,water floats.This means that

A)solid water is less dense than liquid water.
B)organisms in ponds,lakes,and reservoirs can survive under the ice cover.
C)the hydrogen bond arrangement differs between ice and liquid water.
D)All of the choices are correct.

Question 28

From the below table,it is apparent that $$\begin{array} { cc} \text { Bond } & \text { Energy } ( \mathrm { kcal } / \mathrm { mol } ) \\\mathrm { C } - \mathrm { C } & 83 \\\mathrm { C } = \mathrm { C } & 146 \\\mathrm { C } - \mathrm { O } & 84 \\\mathrm { C } = \mathrm { O } & 170\end{array}$$

A)double bonds are stronger than single bonds.
B)double bonds are weaker than single bonds.
C)carbon bonds are the strongest bonds.
D)carbon forms only single bonds.

Question 29

pH 7 has a balanced level of H⁺ and OH^-.

Question 30

A change of one pH unit represents a ten-fold increase or decrease in hydroxide ion concentration.

Question 31

Which of the following substances attract water molecules?

A)a nonpolar substance
B)a polar substance
C)an ionic substance
D)Both polar and ionic substances.
E)All of the above will attract water molecules.

Question 32

The characteristic way in which atoms of an element react is most related to the

A)number of electrons in the valence shell.
B)number of electrons in the innermost shell.
C)number of neutrons in the nucleus.
D)size of the nucleus.

Question 33

All of the following are examples of damage caused by acid deposition from rain EXCEPT

A)leaching of aluminum from the soil into lakes which results in the formation of toxic methyl mercury from mercury in the lake sediments.
B)weakens trees in the forests and kills seedlings.
C)increased agricultural yields.
D)damage to marble and limestone monuments.

Question 34

Draw the structural formula of a single water molecule.Note the location of partial positive and negative charges.Label the covalent bonds.

Question 35

The scale indicates the relative concentrations of hydrogen and hydroxide ions in a solution.

Question 36

Draw several (5 or 6)individual,unbonded water molecules.Simulate what happens when table salt (Na⁺Cl^-)is added to water.Use the model you created to explain why salt is added to the roads in a "snowy," cold climate.

Question 37

Human blood has a pH of about 7.4.This is

A)neutral.
B)very acidic.
C)slightly acidic.
D)slightly basic.

Question 38

Following nitrogen (78%)and oxygen (21%),argon is the next most common gas in the atmosphere (less than 1%).Checking the table of elements,you discover that argon is one of a family of atoms with outer shells already full of electrons.How is this related to the fact that these atoms have virtually no biological importance?

Question 39

Any substance below pH 7 is considered acidic and any substance above pH 7 is considered basic or alkaline.

Question 40

A coastal climate is moderated primarily by which of the following properties of water? Water

A)is the universal solvent.
B)is cohesive and adhesive.
C)has a high heat of evaporation.
D)has a high surface tension.

Question 41

Which term refers to the attraction of water molecules to one another?

A)adhesion
B)cohesion
C)hydrolysis
D)photolysis
E)polarity

Question 42

Which one is NOT one of the properties of water?

A)The frozen form is more dense than the liquid form.
B)Water moderates temperature.
C)Water is a solvent.
D)Water has a high heat capacity.
E)Water has a high heat of evaporation.

Question 43

Which property of water allows it stick to surfaces like glass?

A)adhesion
B)high heat of evaporation
C)high heat capacity
D)Water is a good solvent.
E)The frozen form is less dense than the liquid form.

Question 44

A solution with a pH of 6 has ________ times ________ OH^- than a solution with a pH of 10.

A)40; more
B)4000; less
C)10,000; less
D)4; less
E)10,000 more

Question 45

What is the maximum number of electrons that will be in the first valence shell?

A)two
B)one
C)three
D)six
E)eight

Question 46

Draw two hydrogen atoms using Bohr's model.Now bond them to form a molecule of hydrogen gas.Write the molecular formula.Explain what type of bond you've created and why this is a stable situation.

Question 47

If an element contains eight electrons how many electrons will be placed in the second valence shell?

A)6
B)2
C)8
D)5
E)11

Question 48

The mass number refers to the number of ________ and ________ within an element.

A)protons; neutrons
B)protons; electrons
C)electrons; neutrons
D)protons; molecules
E)electrons; atoms

Question 49

Which substances are on the basic side of the pH scale?

A)baking soda,oven cleaner,and human blood
B)baking soda,oven cleaner,and urine
C)tomatoes,oven cleaner,and human blood
D)beer,vinegar,and black coffee
E)Great Salt Lake,oven cleaner,and tears

Question 50

The electrons are unequally shared in ________,and transferred in ________.

A)H₂O; Na⁺Cl^-
B)O_2; CH₄
C)Na⁺Cl^-; H₂O
D)CH₄; N₂

Question 51

Which type of covalent bond is the strongest?

A)single
B)double
C)triple
D)quadruple
E)All covalent bonds are equal in strength.

Question 52

Use Bohr's model to draw a sodium (Na)atom and a chlorine (Cl)atom.Using your model,explain what happens when sodium reacts with chlorine to form table salt.Include in your explanation ion and ionic bond formation.

Question 53

How many atoms are required to form a molecule?

A)at least two
B)at least three
C)at least four
D)at least five
E)only one

Question 54

This system of chemicals, $\mathrm { II } _ { 2 } \mathrm { CO } _ { 3 } ? \mathrm { II } ^ { + } + \mathrm { IICO } _ { 3 }^-$ ,act as a buffer in the blood.If hydrogen ions are added to blood which of the following reactions would occur?

A) $\mathrm { H } ^ { + } + \mathrm { HCO } _ { 3 } { } ^ { - } \longrightarrow \mathrm { H } _ { 2 } \mathrm { CO } _ { 3 }$
B) $\mathrm { OH }^- + \mathrm { H } _ { 2 } \mathrm { CO } _ { 3 } \longrightarrow \mathrm { HCO } _ { 3 } { } ^ { - } + \mathrm { H } _ { 2 } \mathrm { O }$