Introductory Chemistry Quiz and Exam Answers

Perform the multiplication (2x10^-3)(7x10^-2)

0.00014 or 1.4x10^-5

Convert 8.8x10^-3 to decimal form

0.0088

An unknown element X has the following isotopes: ¹⁰X (20.00% abundant, atomic mass = 10.01 amu) and ¹¹X (80.00% abundant, atomic mass = 10.99 amu). What is the average atomic mass in amu of X?

10.794 amu

What is the mass number for an atom of tin containing 50 protons and 64 neutrons?

114

In an experiment, the reaction of 100.0 g of iodine produced 144.9 g of a compound formed from iodine and fluorine. Given that the mass ratio of iodine to fluorine is 2.23, what is the mass in grams of this compound would be expected to form in the same experiment if you started with 85.2 g of iodine?

123.4 g

A thermometer reads 63.5 °C. What is the temperature in Fahrenheit?

146.3 °F or 146 °F

What is the mass number for an atom of osmium containing 76 protons and 113 neutrons?

189

Write the complete ground-state electron configuration of H⁻.

1s²

Write the complete ground-state electron configuration of Al³⁺.

1s²2s²2p⁶

Write the complete ground-state electron configuration of Al.

1s²2s²2p⁶3s²3p¹

Write the complete ground-state electron configuration of S.

1s²2s²2p⁶3s²3p⁴

Write the complete ground-state electron configuration of Ba²⁺.

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶

Write the complete ground-state electron configuration of Ba.

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²

Write the complete ground-state electron configuration of Ag.

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹4d¹⁰

The number 0.0087 has ___ significant figures.

2

In an experiment, the reaction of 100.0 g of iodine produced 144.9 g of a compound formed from iodine and fluorine. What is the mass ratio of iodine to fluorine in the compound?

2.23

Convert -31.3 °C to K.

241.85 K or 241.9 K

How many protons are in an atom of Co?

27

How many significant figures does the number 67,200 have?

3

What would be the charge on an atom of Ru which only has 41 electrons?

3

Which of the following numbers contains four significant figures? 1561.0 0.053 0.761 3.101 1400

3.101

Arsenic is a toxic solid often used in the past as a component of pesticides. How many electrons are present in a neutral atom of arsenic?

33

An unknown element is a mixture of isotopes ¹⁵¹X (atomic mass = 150.99 amu) and ¹⁵³X (atomic mass = 153.03 amu). The average atomic mass of X is 151.69 amu. What is the percent abundance of ¹⁵³X?

34 %

Perform this mathematical operation and express the answer to the correct number of significant figures: 185,007 ÷ 5301

34.90

How many electrons are in an atom of zirconium with a charge of +2?

38

How many significant figures does the number 1.006 × 10⁷ have?

4

Convert 0.000401 to scientific notation

4.01x10^-4

Perform the subtraction (7.5x10^-4)-(2.6x10^-4)

4.9x10^-4

How many protons are in an atom of zirconium?

40

Convert 163.3 °C to K.

436.45 K or 436.5 K

In an experiment, the reaction of 100.0 g of iodine produced 144.9 g of a compound formed from iodine and fluorine. What mass of fluorine was consumed in the reaction?

44.9 g

Consider an ion, which has 41 protons and 36 electrons. What is the charge on this ion?

5

Counting only s & p electrons, how many valence electrons are present in a neutral atom of arsenic?

5

Perform the subtraction (9.4x10^-6)-(4.4x10^-6)

5.0x10^-6

A cup of hot soup is initially at 85.4 °C, then cools by 33 °C over a period of 25 minutes. What is the value that expresses the new temperature of the soup after 25 minutes using the correct number of significant figures.

52 °C

How many neutrons are in an atom of zirconium with a mass number of 96?

56

An unknown element is a mixture of isotopes ¹²⁹X and ¹³²X. The average atomic mass of X is 130.79 amu. What is the percent abundance of ¹³²X?

59.7 % or 60%

Perform the addition (2.6x10^5)+(3.9x10^5)

6.5x10^5

Convert 0.0000074 to scientific notation

7.4x10^-6

How many electrons are in the n = 2 shell of a magnesium atom?

8

Convert 8.9x10^7 to decimal form

89000000

Convert 0.095 to scientific notation

9.5x10^-2

Convert 95000000000

9.5x10^10

Perform the addition shown (2.5x10^3)+(7.3x10^3)

9.8x10^3

What would be the mass number for an atom of Ru which has 54 neutrons?

98

How many electrons are in the n = 3 shell of a magnesium ion (Mg²⁺)? A) 0 B) 2 C) 8 D) 12

A) 0

Which of the following represents the electron configuration of P³⁻? A) 1s²2s²2p⁶3s²3p⁶ B) 1s²2s²2p⁶3s²3p³ C) 1s²2s²2p⁶3s² D) 1s²2s²2p⁶3s²3p⁶4s¹ E) 1s²2s²2p⁶3s²3p¹

A) 1s²2s²2p⁶3s²3p⁶

Which of the following represents the correct ground-state configuration for a neutral atom of arsenic? A) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³ B) 1s²2s²2p⁶3s²3p⁶4s²4p³ C) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰ D) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

A) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³

What type of bonding is present in H₂O₂? A) Covalent bonds only B) Ionic bonds only C) Both covalent and ionic bonds D) Neither covalent nor ionic bonds

A) Covalent bonds only

Which is a method for separating a liquid-liquid mixture, such as water and acetone? A) distillation B) filtration C) chromatography D) paper chromatography

A) Distillation

A sample of iron is an example of a(n) A) Element B) Compound C) Mixture

A) Element

The accepted value for the density of iron is 7.9 g/mL. Which of the following sets of experimental data for the density of iron is the most accurate? A) Group 1: 7.98 g/mL, 7.85 g/mL B) Group 2: 7.65 g/mL, 7.64 g/mL C) Group 3: 7.03 g/mL, 8.54 g/mL D) Group 4: 5.43 g/mL, 5.47 g/mL

A) Group 1: 7.98 g/mL, 7.85 g/mL

The element symbol for nickel is _____ A) Ni B) N C) Nc D) Ne E) Nh

A) Ni

Ni has a higher atomic number than Co, but Co has a higher atomic mass. Co-59 has a 100% natural abundance. The 5 stable isotopes of Ni are Ni-58, Ni-60, Ni-61, Ni-62, and Ni-64. Which Ni isotope has the highest natural abundance? A) Ni-58 B) Ni-60 C) Ni-61 D) Ni-62 E) Ni-64

A) Ni-58

Of the following compounds, which contains a metalloid? A) SiF₄ B) SCl₂ C) In₂O₃ D) Sn(C₂H₅)₄ E) Bi₂S₃

A) SiF₄

Which of the following species has the same number of electrons as Cl⁻? A) S²⁻ B) Br⁻ C) F⁻ D) P³⁺ E) K⁻

A) S²⁻

The atomic mass of germanium (Ge) on the periodic table is 72.630 amu. Which of the following best explains why the atomic mass is a fraction between 72 and 73? A) The presence of different isotopes B) The presence of different isomers. C) The formation of different ions. D) The presence of different allotropes. E) The presence of different amounts of protons.

A) The presence of different isotopes

Consider an atom of zirconium which has a mass number of 96. What is the chemical symbol of this element? A) Zr B) Zi C) Z D) Zn

A) Zr

For each of the following atoms or ions, determine the correct ground state electron configuration. Iodine, I A) [Kr]5s²4d¹⁰5p⁵ B) [Kr]5s²4d¹⁰5p⁶ C) 5s²4d¹⁰5p⁵ D) [Kr]5s²5p⁵

A) [Kr]5s²4d¹⁰5p⁵

The process of fermentation is example of A) a chemical change B) a mixture C) a physical change D) an intensive property

A) a chemical change

Classify each of the following compounds as ionic or covalent. HNO₃ A) covalent B) ionic

A) covalent

Classify each of the following compounds as ionic or covalent. PI₅ A) covalent B) ionic

A) covalent

What type of element is Zr? A) metal B) metalloid C) nonmetal

A) metal

Consider an ion, which has 41 protons and 36 electrons. What period is this element found in? A) the fifth period B) the fourth period C) the sixth period D) the third period

A) the fifth period

Accuracy definition help

Accuracy is when the average of the set of measurements is in the range of uncertainty of the accepted value

Which of the following represents the electron configuration of S⁻? A) 1s²2s²2p⁶3s²3p⁶ B) 1s²2s²2p⁶3s²3p⁵ C) 1s²2s²2p⁶3s²3p⁴ D) 1s²2s²2p⁶3s²3p³ E) 1s²2s²2p⁶3s²3p²

B) 1s²2s²2p⁶3s²3p⁵

How many neutrons are in a ⁴He atom? A) 0 B) 2 C) 4 D) 6

B) 2

A student has a body mass of 175.5 pounds. He steps onto a scale holding a 25.0-pound barbell. Choose the value that expresses the combined mass of the student and the barbell using the correct number of significant figures. A) 200 lbs B) 200.5 lbs C) 200.50 lbs D) 205 lbs E) 150.5 lbs

B) 200.5 lbs

An atom of the isotope ¹³³Cs contains how many protons (p), neutrons (n), and electrons (e)? A) 55 p, 55 n, 55 e B) 55 p, 78 n, 55 e C) 133 p, 133 n, 133 e D) 55 p, 133 n, 55 e E) 133 p, 55 n, 55 e

B) 55 p, 78 n, 55 e

Determine the number of protons (p) and electrons (e) in N³⁻. A) 10 p, 7 e B) 7 p, 10 e C) 7 p, 7 e D) 7 p, 9 e E) 10 p, 10 e

B) 7 p, 10 e

How many electrons are in the n = 3 shell in a neutral calcium atom? A) 2 B) 8 C) 18 D) 20

B) 8 Calcium has 8 electrons in the nn = 3 shell. Calcium has an electron configuration of 1s2 2s2 2p6 3s2 3p6 4s21s2 2s2 2p6 3s2 3p6 4s2. Calcium has full 3s and 3p subshells, which can hold 2 and 6 electrons respectively.

An atom has nine protons and ten electrons. This makes it: A) Nonstoichiometric B) An ion C) A cathode ray D) An alpha particle E) Neutrally charged

B) An ion

Which element has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p²? A) Si B) Ge C) Sn D) Ga E) As

B) Ge

Which of the following statements about subatomic particles are true? I. Protons and neutrons have charges of opposite signs but the same magnitude. II. Protons and neutrons have about the same mass. III. A neutral atom always has the same number of neutrons and electrons. A) I only B) II only C) III only D) II and III E) I and II

B) II only

Which of the following is best classified as a covalent (molecular) compound? A) Sr₃N₂ B) N₂O₅ C) Li₃N D) AlN

B) N₂O₅

Which of the following is most likely to make a -3 ion? A) Al B) P C) Be D) Se E) Bi

B) P

Which two particles of the atom have nearly identical masses? A) Proton and electron B) Proton and neutron C) Neutron and electron D) No two particles have similar masses

B) Proton and neutron

The nucleus of an atom contains: A) Protons and electrons B) Protons and neutrons C) Electrons and neutrons D) Protons, neutrons and electrons E) Electrons only

B) Protons and neutrons

What element with a mass number of 100 has 56 neutrons in its nucleus? A) Fermium (Fm) B) Ruthenium (Ru) C) Barium (Ba) D) Copernicium (Cn) E) Radium (Ra)

B) Ruthenium (Ru)

Which two element from Group IVA (Group 14) of the periodic table are considered to be metalloids. A) Carbon & silicon B) Silicon & germanium C) Germanium & tin D) Tin & lead

B) Silicon & germanium

For each of the following atoms or ions, determine the correct ground state electron configuration. Tin, Sn A) [Kr]5s²5p² B) [Kr]5s²4d¹⁰5p² C) [Kr]5s²4d¹⁰3f¹⁴5p² D) [Kr]5p²

B) [Kr]5s²4d¹⁰5p²

For each of the following atoms or ions, determine the correct ground state electron configuration. I⁻ A) [Kr]5s²4d¹⁰5p⁵ B) [Kr]5s²4d¹⁰5p⁶ C) 5s²4d¹⁰5p⁶ D) [Kr]5s²5p⁶

B) [Kr]5s²4d¹⁰5p⁶

What type of element is Ru? A) an alkali metal B) a transition metal C) a lanthanide D) an alkaline earth metal

B) a transition metal

Which of the following has two valence electrons? A) potassium B) helium C) oxygen D) argon

B) helium

Classify each of the following compounds as ionic or covalent. Ca₃N₂ A) covalent B) ionic

B) ionic

Classify each of the following compounds as ionic or covalent. CoBr₂ A) covalent B) ionic

B) ionic

What is the name of the SI unit for length? A) kilogram B) meter C) second D) Kelvin

B) meter

Atoms from which of the following pairs are most likely to form an ionic bond? A) sodium and potassium B) titanium and oxygen C) sodium and barium D) nitrogen and fluorine

B) titanium and oxygen

Which of the orbital electron configurations is not possible? A) 2s¹ B) 3d¹⁰ C) 4p⁷ D) 4f⁷ E) 2p⁶

C) 4p⁷

The number 0.00000620 written in scientific notation would be A) 6.20 × 10⁻⁵ B) 6.20 × 10⁵ C) 6.20 × 10⁻⁶ D) 6.20 × 10⁶

C) 6.20 × 10⁻⁶

Which of the following species has the same number of protons as Fe³⁺? A) Mn³⁺ B) Co²⁺ C) Fe²⁺ D) Ni⁺ E) Co³⁺

C) Fe²⁺

Which of the following statements about subatomic particles are false? I. Some atoms do not have any neutrons. II. Protons and neutrons reside in the nucleus. III. Some atoms do not have any protons. A) I only B) II only C) III only D) II and III E) I and II

C) III only

What is the noble gas core in the electron configuration for Sb? A) Ne B) Ar C) Kr D) Xe E) Rn

C) Kr

Milk is an example of a(n) A) Element B) Compound C) Mixture

C) Mixture

Consider an ion, which has 41 protons and 36 electrons. What is the chemical symbol of this element? A) Ca B) Ni C) Nb D) Kr

C) Nb

Which element has the ground state electron configuration [Kr]5s²4d¹⁰5p³? A) Te B) Pb C) Sb D) Bi E) Sn

C) Sb

Which of the following is NOT an alkali or alkaline earth element? A) Ra B) Cs C) Sc D) Be E) Rb

C) Sc

How do you convert a Fahrenheit temperature to Celsius? A) Multiply by 9/5 and then add 32 B) Subtract 273.15 C) Subtract by 32, then multiply by 5/9 D) Add 273.15 E) Celsius is always the same as Kelvin

C) Subtract by 32, then multiply by 5/9

The process of filtration is example of A) a chemical change B) a chemical reaction C) a physical change D) an intensive property

C) a physical change

Which of the following has seven valence electrons? A) nitrogen B) calcium C) bromine D) phosphorus

C) bromine

The net charge on an atom of a given element changes as ______ are added or removed. A) neutrons B) protons C) electrons D) protons and electrons

C) electrons

Barium sulfate (BaSO₄) is used in certain imaging techniques as a radiopaque contrast media. Barium sulfate is a(n) ______. A) molecular compound B) molecular element C) ionic compound D) monatomic element

C) ionic compound

Which of the following sets of elements and symbols is paired incorrectly? A) lithium, Li B) arsenic, As C) silver, Si D) gallium, Ga E) zinc, Zn

C) silver, Si

What is the electron configuration of Co²⁺? A) 1s²2s²2p⁶3s²3p⁶3d⁵ B) 1s²2s²2p⁶3s²3p⁶4s²3d⁵ C) 1s²2s²2p⁶3s²3p⁶4s²3d⁹ D) 1s²2s²2p⁶3s²3p⁶3d⁷ E) 1s²2s²2p⁶3s²3p⁶3d⁹

D) 1s²2s²2p⁶3s²3p⁶3d⁷

Which of the following represents the correct ground-state configuration for the arsenide ion? A) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³ B) 1s²2s²2p⁶3s²3p⁶4s²4p³ C) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰ D) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

D) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶ The arsenide ion has a -3 charge

Of the following, which sublevel is filled last? A) 3d B) 4s C) 4p D) 4d E) 5s

D) 4d

How many valence electrons are in a neutral atom of oxygen? A) 0 B) 2 C) 4 D) 6 E) 8

D) 6

Which postulate(s) of Dalton's atomic theory of matter is/are NOT true? I. Atoms of a given element are identical II. Atoms are indestructible III. Atoms combine in simple ratios to form compounds A) I only B) II only C) III only D) Both I and II

D) Both I and II

Which scientist developed the nuclear model of the atom? A) John Dalton B) J. J. Thomson C) Robert Millikan D) Ernest Rutherford E) James Chadwick

D) Ernest Rutherford

What group (G) and period (P) does the element molybdenum (Mo) belong to? A) G = 5, P = 6 B) G = 6, P = 6 C) G = 6, P = 4 D) G = 6, P = 5 E) G = 5, P = 5

D) G = 6, P = 5

Columns on the periodic table are known as A) Periods B) Halogens C) Metals D) Groups E) Metalloids

D) Groups

Classify the following compounds as ionic or covalent (molecular): BaO, Fe₂O₃, ZnO. A) Covalent, covalent, covalent. B) Ionic, ionic, covalent. C) Ionic, covalent, covalent. D) Ionic, Ionic, Ionic.

D) Ionic, Ionic, Ionic.

For each of the following atoms or ions, determine the correct ground state electron configuration. Sn⁴⁺ A) [Kr]5s² B) [Kr]5s²4d⁸ C) [Kr]5s²4d⁶5p² D) [Kr]4d¹⁰

D) [Kr]4d¹⁰

Consider the atom with the chemical symbol Ru. What is the name of this element? A) rutherfordium B) rhodium C) rhenium D) ruthenium

D) ruthenium

Which of the following is NOT a type of scientific observation? A) Quantitative B) Qualitative C) Direct (sensory) D) Indirect (instrumental) E) Hypothetical

E) Hypothetical

Which of the following statements about subatomic particles are true? I. Protons and electrons have charges of opposite signs but the same magnitude. II. Protons have twice the mass of neutrons. III. Electrons are lighter than neutrons. A) I only B) II only C) III only D) II and III E) I and III

E) I and III

Which of the following is most likely to form a +2 ion? A) K B) Sc C) Al D) O E) Mg

E) Mg

What is the noble gas core in the electron configuration for U? A) Ne B) Ar C) Kr D) Xe E) Rn

E) Rn

A theory is another word for a(n) _________. A) model B) law C) measurement D) experiment

Model

How to solve previous problem

The atomic mass is an average that represents the abundance of each isotope. It can be calculated by multiplying each atomic mass by its abundance in decimal form and adding them together. (0.2000×10.01amu)+(0.8000×10.99amu)=10.794amu

How many significant figures to use in the last question?

To calculate the lower temperature based on a decrease in temperature known to a lower level of precision than the initial temperature, the difference should have the same number of digits to the right of the decimal place as the less precise decrease. In this case, the change in temperature is reported with zero digits to the right of the decimal, and so is the final temperature: 85.4ºC−33ºC=52ºC

Write the condensed (noble-gas) electron configuration of C.

[He]2s²2p²

Convert 7.4x10^-6 to decimal form

0.0000074

Perform the multiplication (3x10^2)(2x10^-7)

0.00006 or 6x10^-5

The element symbol for lead is __. A) La B) Le C) Sb D) Lu E) Pb

E) Pb

Reasoning behind last answer

When dividing numbers, the result is reported with the significant figures of the number in the calculation with the least significant figures