Deck 2: Atoms and Molecules

Question 1

Isotopes differ from each other in what way?

A)They have different numbers of protons in the nucleus.
B)They have different numbers of neutrons in the nucleus.
C)They have different numbers of electrons outside the nucleus.
D)More than one response is correct.

Answer 1

They have different numbers of neutrons in the nucleus.

Question 2

Which of the following particles is the smallest?

A)proton
B)electron
C)neutron
D)they are all the same size

Answer 2

electron

Question 3

The average relative mass of an ozone molecule is 48.0 u. An ozone molecule contains only oxygen atoms. What does this molecular weight indicate about the formula of the ozone molecule?

A)It is monoatomic.
B)It is diatomic.
C)It is triatomic.
D)Impossible to determine

Answer 3

It is triatomic.

Question 4

How many electrons are in a neutral atom of carbon-13 (¹³C)?

A)6
B)18
C)12
D)no way to tell

Question 5

Refer to a periodic table and tell how many helium atoms (He)would be needed to get close to the same mass as an average oxygen atom (O).

A)six
B)four
C)twelve
D)one-fourth

Question 6

Which of the following carries a negative charge?

A)a proton
B)a neutron
C)an electron
D)both proton and neutron

Question 7

What is meant when the symbol C-12 (or ¹²C)is used?

A)the carbon atom weighs 12 grams
B)the carbon atom weighs 12 pounds
C)the carbon atom weighs 12 amu
D)the melting point of carbon is 12°C

Question 8

What is the meaning of the two (2)in ethyl alcohol, C₂H₅OH?

A)all alcohol molecules contain two carbon atoms
B)there are two carbon atoms per molecule of ethyl alcohol
C)carbon is diatomic
D)all of these are correct statements

Question 9

Which of the following is located in the nucleus of an atom?

A)protons
B)neutrons
C)electrons
D)protons and neutrons

Question 10

What is the reason that U-238 is different from U-235?

A)three more electrons
B)three more protons
C)three more neutrons
D)there is no difference

Question 11

Using whole numbers, determine the molecular weight of calcium hydroxide, Ca(OH)₂.

A)56
B)57
C)58
D)74

Question 12

The symbols for elements with accepted names

A)consist of a single capital letter.
B)consist of a capital letter and a small letter.
C)consist of either a single capital letter or a capital letter and a small letter.
D)No answer is correct.

Question 13

How many neutrons are found in the nucleus of a boron-11 (¹¹B)atom?

A)11
B)6
C)5
D)4

Question 14

Which of the following uses the unit of "u" or "amu"?

A)atomic weights of atoms
B)relative masses of atoms
C)molecular weights of molecules
D)more than one response is correct

Question 15

How many protons are found in the nucleus of a boron-11 (¹¹B)atom?

A)11
B)6
C)5
D)4

Question 16

A molecular formula

A)is represented using the symbols of the elements in the formula.
B)is represented using a system of circles that contain different symbols.
C)cannot be represented conveniently using symbols for the elements.
D)is represented using words rather than symbols.

Question 17

Why is CaO the symbol for calcium oxide instead of CAO?

A)both can be the symbols for calcium oxide
B)both are incorrect; the symbol is cao
C)a capital letter means a new symbol
D)both are incorrect as the symbol should be CaO_x

Question 18

Determine the molecular weight of hydrogen peroxide, H₂O₂, in u (or amu).

A)17.01
B)18.02
C)34.02
D)33.01

Question 19

Which of the following pairs are about equal in mass?

A)proton and electron
B)electron and neutron
C)proton and neutron
D)nucleus and surrounding electrons

Question 20

Atoms are neutral. How can they have no charge?

A)equal numbers of protons and neutrons
B)equal numbers of protons and electrons
C)equal numbers of neutrons and electrons
D)any charge has been drained out of the atom

Question 21

Naturally occurring lithium (Li)consists of only two isotopes, Li-6 (6.02 u)and Li-7 (7.02 u), where the isotopic masses are given in parentheses. Use the periodic table and determine which isotope is present in the larger percentage in the natural element.

A)Li-6
B)Li-7
C)each is present at 50%
D)cannot be determined from the information available

Question 22

Which element is approximately 65 percent of sulfuric acid by weight?

A)hydrogen
B)sulfur
C)oxygen
D)any of these

Question 23

The formula for dinitrogen monoxide is N₂O. If a sample of the oxide was found to contain 0.0800 g of oxygen, how many grams of nitrogen would it contain?

A)0.140
B)0.280
C)0.560
D)0.0700

Question 24

The number of Cr atoms in a 26.0 g sample of chromium is x. How many atoms, expressed in terms of x, would be contained in 26.98 g of aluminum (Al)?

A)x
B)x\2
C)2x
D)x+2

Question 25

What is the weight percentage of nitrogen in urea, CN₂H₄O?

A)46.7
B)30.4
C)32.6
D)16.3

Question 26

What mass of arsenic (As)in grams contains the same number of atoms as 39.95 g of argon (Ar)?

A)33.0
B)74.92
C)4.16
D)149.84

Question 27

How many silicon atoms (Si)are contained in a 12.5 g sample of silicon?

A)2.68 × 10²³
B)5.83 × 10 ^{− 22}
C)1.35 × 10²⁴
D)1.71 × 10²¹

Question 28

One Avogadro's number of iron (Fe)atoms would weigh _____ .

A)55.9 g.
B)6.02 × 10²³ g.
C)55.9 u.
D)6.02 × 10 ^{− 23} g.

Question 29

Calculate the weight percentage of hydrogen in water.

A)33.3
B)66.7
C)2.00
D)11.1

Question 30

How many moles of oxygen atoms are in one mole of CO₂?

A)1
B)2
C)6.02 × 10²³
D)12.04 × 10²³

Question 31

How many moles of N₂O contain the same number of nitrogen atoms as 4.60 g of NO₂?

A)0.500
B)0.0500
C)0.100
D)0.200

Question 32

Naturally occurring neon (Ne)has the following isotopic composition (the mass of each isotope is given in parenthesis). Calculate the atomic weight of neon in u from these data:  neon-20, 90.92% (19.99 u); neon-21, 0.257% (20.99 u); neon-22, 8.82% (21.99 u)

A)28.97
B)37.62
C)2017
D)20.17

Question 33

How many moles of hydrogen molecules (H₂)would be required to produce two moles of hydrogen peroxide (H₂O₂)?

A)1
B)2
C)3
D)4

Question 34

How many hydrogen atoms are in 1.00 mole of NH₃?

A)3.00
B)6.02 × 10²³
C)12.0 × 10²³
D)18.1 × 10²³

Question 35

How many atoms are contained in a sample of krypton, Kr, that weighs 8.38 g?

A)one Avogadro's number
B)one-tenth Avogadro's number
C)one
D)one-tenth

Question 36

How many carbon atoms are contained in 5.50 g of ethane, C₂H₆?

A)2.75 × 10 ^{− 22}
B)3.29 × 10²⁴
C)1.10 × 10²³
D)2.21 × 10²³

Question 37

What is the mass number of a carbon-13 (¹³C)atom?

A)13
B)12
C)6
D)7

Question 38

The mass of mercury (Hg), a liquid at room temperature, is 200.6 amu\mol. A 200.6 gram sample of mercury is heated until it boils. What is the mass of one mole of mercury vapor (gas)?

A)200.6 or it wouldn’t be a gas
B)the same as Avogadro's number
C)the same as when it is a liquid
D)none of the answers are correct

Question 39

Which of the following has the largest mass?

A)5.0 mol H₂O
B)3.5 mol NH₃
C)8.0 mol C
D)6.0 mol C₂H₂

Question 40

What is the number of hydrogen atoms in a 18.016 gram sample of water?

A)2.000
B)6.022 × 10²³
C)18.02
D)1.204 × 10²⁴

Question 41

Which of the following correctly describes subatomic particles? 1. Mass:   < = n
2. Magnitude of charge:   n = 3. Location:   outside nucleus   ,   , inside nucleus     n

A)1 only
B)2 only
C)3 only
D)1 and 2

Question 42

Atoms that have the same atomic number but differ by mass number are called?

A)protons
B)neutrons
C)isotopes
D)positrons

Question 43

The weight % of S in K₂SO₄ is _____ .

A)14.2%
B)18.4%
C)54.4%
D)22.4%

Question 44

Write the formula for a compound consisting of 3 sodium atoms, 1 phosphorus atom, and 4 oxygen atoms.

A)S₃PO₄
B)3NaP4O
C)Na₃P2(O₂)
D)Na₃PO₄

Question 45

Determine the number of electrons and protons in the element Tc.

A)43 protons, 43 electrons
B)43 protons, 56 electrons
C)56 protons, 43 electrons
D)99 protons, 43 electrons

Question 46

How many moles of Na₂Cr₂O₇ contain 14 moles of oxygen atoms?

A)2 mol Na₂Cr₂O₇
B)14 mol Na₂Cr₂O₇
C)7 mol Na₂Cr₂O₇
D)1 mol Na₂Cr₂O₇

Question 47

Approximately, how many atoms of beryllium would be required to equal the mass of 10 atoms of aluminum?

A)3 atoms of beryllium
B)10 atoms of beryllium
C)30 atoms of beryllium
D)4 atoms of beryllium

Question 48

If you have 3.011 × 10²³ atoms of carbon, what would you expect its mass to be?

A)12.01 g
B)6.005 g
C)3.003 g
D)1.000 g

Question 49

What is the molar mass of Ba₃(PO₄)₂?

A)232.30 g\mol
B)327.27 g\mol
C)369.63 g\mol
D)601.92 g\mol

Question 50

The system of atomic mass units is based on

A)assigning ¹²C as weighing exactly 12 u & comparing other elements to it.
B)measuring the true mass of each subatomic particle.
C)comparing the differences in protons and electrons.
D)viewing how atoms are affected by electromagnetic fields.

Question 51

How many electrons are found around the species below?

A)-2
B)0
C)2
D)4

Question 52

A neutral isotope of an element contains 21 electrons and 24 neutrons.  What is the following representation for this nucleus?

A)
B)
C)
D)

Question 53

An isotope of a given element has a mass number equal to twice the atomic number.  This neutral isotope contains twelve electrons.  This isotope is _____ .

A)magnesium-12.
B)magnesium-24.
C)chromium-24.
D)chromium-12.

Question 54

Consider the representation shown below.  It should be classified as

A)an element consisting of 6 atoms.
B)a compound containing atoms of two elements.
C)a homogenous mixture of two elements.
D)a homogenous mixture of two compounds.

Question 55

If calcium carbonate found in limestone is 40.0% calcium, how many grams of calcium are in 485 g of calcium carbonate?

A)12.1 g of calcium
B)291 g of calcium
C)19,400 g of calcium
D)194 g of calcium

Question 56

How many neutrons are in an atom that has a mass number of 75 and contains 35 protons?

A)40
B)35
C)75
D)can't tell

Question 57

How many grams of iron (Fe)is contained in 15.8 g of Fe(OH)₃?

A)12.1
B)8.26
C)11.8
D)5.21

Question 58

What is wrong with the following molecular formula: SOO (sulfur dioxide)?

A)OSO is the correct form
B)SO should be So
C)OO should be written as O2
D)OO should be written as O₂

Question 59

What is the number of moles of water in one liter of water if one gram of water takes up one milliliter of space?

A)1
B)18
C)55.6
D)1000

Question 60

The symbol for bromine is _____ .

A)B
B)Br
C)Be
D)none of these

Question 61

A mole of copper contains the same number of atoms as a mole of zinc.

Question 62

One mole of silver would contain the same number of atoms as a mole of gold.

Question 63

The symbols for all of the elements always begin with a capital letter.

Question 64

One mole of an element would weigh the same as a mole of an isotope of the same element.

Question 65

The most accurate way to determine atomic mass is with a mass spectrometer.

Question 66

One mole of an element would weigh the same as a mole of an isotope of the same element.

Question 67

One mole of H₂O contains 2.0 grams of hydrogen.

Question 68

You discover a new element which consists of two isotopes.  The first isotope, ²⁴³X (mass = 242.45 u)  comprises 40.000% of the total.  The second isotope, ²⁴⁸X (mass = 247.11 u)accounts for the rest.  What would be the average atomic mass for your new element?

A)242.45 u
B)244.32 u
C)245.25
D)247.11

Question 69

Isotopes of the same element always have the same atomic number.

Question 70

One mole of O₃ weighs 16 grams.

Question 71

Isotopes of the same element always have the same atomic mass.

Question 72

H₂O₂ contains equal parts by weight of hydrogen and oxygen.

Question 73

Individuals, ages 19-70, should include at least 1000 mg of calcium in their daily diet.  What is the minimum number of one-gram calcium supplement tablets you would need to take each day to meet this requirement if a tablet is 40% by mass calcium?

A)1
B)2
C)3
D)4

Question 74

The symbols for all of the elements are derived from the Latin names.

Question 75

The first letter of the symbol for each of the elements is the first letter of its English name.

Question 76

Oxalic acid is found in many plants, like spinach and black tea.  What is the mass of the carbon found in one mole of oxalic acid, H₂C₂O₄?

A)12.01 g of C
B)24.02 g of Cl
C)45.01 g of C
D)90.02 g of C

Question 77

is the form of uranium used to make atomic bombs.  One atom of this isotope consists of ___.

A)92 protons, 92 electrons, 92 neutrons
B)92 protons, 143 electrons, 92 neutrons
C)92 protons, 92 electrons. 143 neutrons
D)143 protons, 143 electrons, 92 neutrons

Question 78

The charge of the nucleus depends only on the atomic number.

Question 79

Isotopes of the same element always have the same number of neutrons.

Question 80

Electrons do not make an important contribution to the mass of an atom.