Chemistry for Engineers

Copper, Cu, has two stable isotopes, 63Cu with atomic mass of 62.9 amu and 65Cu with atomic mass of 64.93 amu. The average atomic mass of Cu is 63.54. What are the percent abundances of the two isotopes?

• 99% 63Cu and 1% 65Cu
• 69.5% 63Cu and 30.5 65Cu
• 1% 63Cu and 99% 65Cu
• 30.5% 63Cu and 69.5 65Cu

One mole of N2 contains 2*6.022 x 1023 molecules.

• True
• False

In reference to item 13, suppose synthesis of Al2O3 is done in the lab using 20.50 g of Al and excess of O2. Upon purification, 30.33 grams of Al2O3 is produced. What is the percent yield of Al2O3?

• 39.15%
• 78.29%
• 147.95%
• 67.58%

Elements are arranged in the periodic table in order of increasing atomic number.

• True
• False

Dalton's law of partial pressure states that constant temperature and volume, the total pressure of a gas is ____________ proportional to the number of moles of gas present.

• sometimes inversely, sometimes directly
• directly
• inversely

Using the periodic table, which element is in Group 2A period 5?

• Sr
• N
• Ba
• Ra

Which gas law states that at at constant temperature and pressure, volume of gas is directly proportional to the number of moles of gas present.

• Charle's Law
• Avogadro's Law
• Boyle's Law
• Ideal Gas Law

The number of electrons and protons are equal in number.

• True
• False

What is the name of the compound that has 2 sulfur and 10 fluorine?

• bisulfurdecafluoride
• disulfurdecafluoride
• sulfur decafluorine
• sulfur (II) fluoride

How many significant figures are in 0.000187?

• 3
• 5
• 6
• 4

The difference between the mass number and the atomic number equals the number of ________________ in an atom.

• Protons
• Electrons
• Neutrons

Which of the following increases as work increases?

• Distance
• Both force and distance
• Force
• No correct answer

AB4+2C2->AC2+2B2C. If 100 grams of AB4 reacts with excess of C2, it will produce 100 grams of AC2.

• True
• False

Suppose 20.50 g of Al reacts with excess O2, how many grams of Al2O3 is produced? (Molar Mass of Al2O3 is 101.96 g/mol)

• 10.85 grams
• 77.47 grams
• 38.74 grams
• 154.94 grams

The -ium ending on the name of hydronium indicates that it is a cation from metal atoms.

• True
• False

How many significant figures are in 4.0300 x 103 g?

• 5
• 2
• 3
• 4

Compute the area given the following measurements: 3.7552 cm and 1.7 cm. Express the answer in significant figures.

• 6.42 cm2
• 6 cm2
• 6.4178 cm2
• 6.4 cm2

What is defined as the amount of heat needed to raise the temperature of 1gram of the substance by 1K or 1C?

• Kinetic energy
• Enthalpy
• Heat capacity
• Specific heat

Pressure is defined as the effect of a force applied to a surface and can be measured by means of a barometer or manometer.

• True
• False

If 2 moles of AB4were made to react with 2 moles of C2, 1 moles of AC2 will be produced.

• True
• False

How many grams of Carbon are in 600 grams of Resveratrol?

• 815.21 grams
• 63.96 grams
• 36.8 grams
• 441.97 grams

In a balanced chemical equation, the number of atoms of an element on the left side is always equal to the number of atoms on the right side.

• True
• False

One mole of Phosphorus, with atomic mass of 30.97 amu, has greater number of atoms than one mole of Boron, with atomic mass of 10.81 amu.

• True
• False

Which ion is not correctly named?

• Ca2+, calcium (II) ion
• O22-, peroxide ion
• None of these
• Cr3+, chromium (III) ion

How many significant figures are in 0.0054

• 2
• 3
• 4
• 5

What is defined as the described as the sum of the internal energy and product of pressure and volume in a system?

• Heat capacity
• Kinetic energy
• Enthalpy
• Specific heat

As the mass or speed increases, kinetic energy decreases.

• True
• False

Kinetic energy is expressed as:

• Ek = 1/2 mv^2

Ideal Gas Law is expressed as PV=nRT.

• True
• False

Which of the following is the correct formula of sulfurous acid?

• H2SO3
• HS
• HSO3
• H2S

Which of the following statement is not correct?

• Molecular formula shows only the relative ratio of each of each atom in a molecule
• Empirical formula shows the actual number of atoms in a molecule.
• Both of the given choices are correct
• None of the choices

Which gas law states that at a constant temperature, the volume of a fixed amount of gas is inversely proportional to its pressure?

• Avogadro's Law
• Boyle's Law
• Charle's Law

What is the mass percent of Hydrogen, H, in resveratrol?

• 18.83%
• 5.31%
• 19.02%
• 5.26%

______________ are elements located in rows, while ________ are elements located in columns

• gases; period
• group; period
• no correct answer
• period; group

___________________ is a combination of Boyle's, Charle's and Avogadro's laws.

• No correct answer
• Kinetic Molecular Theory of Gases
• Dalton's Law of Partial Pressures
• Ideal Gas Law

What is the name of the compound that has 2 nitrogen and 4 oxygen?

• nitrogen (II) oxide
• nitrogen tetroxide
• dinitrogen tetroxide
• binitrogen tetroxide

Which of the following statement is true regarding Ideal Gas Law?

• Expressed as PV=nRT
• is a combination of Boyle’s, Charle’s and Avogadro’s laws
• All of the choices

Which of the following statement is not true according to Dalton's atomic theory ?

• Elements are made up of extremely tiny particles called atoms.
• Compounds are made up of a combination of atoms of more than one element
• None of the choices
• Atoms are can be created or destroyed in a chemical reaction.
• All atoms of a given element are the same, but atoms of one element are different from the atoms of all other elements.

Which of the following statement is true regarding Gas Laws?

• Charle's Law states that at constant temperature and pressure, volume of gas is directly proportional to the number of moles of gas present
• All of the choices
• Boyle's Law states that at a constant temperature, the volume of a fixed amount of gas is inversely proportional to its pressure
• Avogadro's law states that at constant pressure, the volume of a fixed amount of gas is directly proportional to its absolute temperature

A percent yield of 100% is impossible to attain in the laboratory.

• True
• False

Gases take up volume and shape of its container, are considered the least compressible state of matter and have the lowest density compared to solids and liquids.

• True
• False

The internal energy of a system increases when heat is applied of work is done into it.

• True
• False

Higher temperature in gas means higher ____________.

• Velocity and Kinetic energy
• velocity
• None of the choices
• kinetic energy

How many significant figures are in 0.00002?

• 1
• 6
• 5
• 3

Which of the following statement is true regarding matter?

• States of matter can be converted from one state to another by having changes in temperature
• Both of the given choices are correct
• States of matter can be converted from one state to another by having changes in pressure
• No correct answer

Suppose synthesis of Al2O3 is done in the lab using 20.50 g of Al and excess of O2. Upon purification, 35.48 grams of Al2O3 is produced. What is the percent yield of Al2O3?

• 91.58%
• 45.80%
• 57.78%
• 22.90%

Which of the following statement is not true regarding kinetic molecular theory?

• Forces between gas molecules, whether attractive or repulsive, are negligible.
• Energy can be transferred when molecules collide with one another. However, at constant temperature, the average kinetic energy remains unchanged.
• Total volume of all the gas molecules is negligible in relation to the total volume where the gas is contained.
• Gases are composed of large numbers of molecules that are in constant, random motion.
• Average kinetic energy of gas molecules is proportionate to absolute temperature. At any given temperature, gas molecules have exactly similar average kinetic energy.
• None of the choices

Iron, Fe, has an atomic mass of 55.85 amu therefore, the molar mass of Fe is 55.85 g/mol.

• True
• False

Dalton's law of partial pressure states that constant _____________ and volume, the total pressure of a gas is directly proportional to the number of moles of gas present.

• temperature
• distance
• pressure
• any of the given choices is correct

Which of the following statement is true regarding balancing chemical equations?

• Both of the given statements are correct
• Balance first those elements that appear in only one reactant and one product. Then, balance elements that appear in more than one reactant and product.
• No correct answer
• The common convention for balanced equations is to use the smallest whole numbers

How many moles of Al is needed to produce 4 moles of Al2O3

• 2 moles
• 8 moles
• 1 mole
• 4 moles

Accuracy is a measure of how closely individual measurements are to the actual or true value, while precision refers as to how closely individual measurements are to one another.

• True
• False

Charle's Law states that at a constant pressure, the volume of a fixed amount of gas is inversely proportional to its absolute temperature

• True
• False

The empirical formula of an unknown compound was determined to be CH2O. A separate analysis to determine the molar mass was done. Results show that the molar mass is 360.36 g/mol. What is the molecular formula of the unknown compound?

• Cannot be determined
• C12H24O12
• C6H12O6
• C3H6O3

Atomic number plus the number of neutrons is referred to as:

• Mass number
• None of the choices
• Isotopes
• Atomic number

Aluminum oxide, Al2O3, is synthesized by the reaction of aluminum, Al, and oxygen gas, O2. Which of the following equations correctly represent the reaction?

• Al + O2 → Al2O3
• 4Al + 3O2 → 2Al2O3
• 2Al + 3O2 → 2Al2O3
• 2Al + O3 → Al2O3

How many atoms of oxygen are in 1 mole of Resveratrol?

• 2.01 x 1023
• 12.04 x 1023
• 6.02 x 1023
• 18.06 x 1023

Molar heat capacity is the amount of heat needed to raise the temperature of 1 mole of a substance by 1K or one degree celsius.

• True
• False

Elements can be decomposed into smaller substances.

• True
• False

As long as we use stoichiometric amounts of reactants in a reaction carried out in the laboratory, we are guaranteed to get the theoretical yield of the reaction.

• True
• False

Convert 35.6 degrees Celsius to Fahrenheit

• 96.1 degrees Fahrenheit
• 2 degrees Fahrenheit
• 308.75 degrees Fahrenheit
• 69.1 degrees Fahrenheit

Partial pressure is defined as the amount of pressure exerted by each component gas in a mixture, which is independent of the pressure exerted by the other gases.

• True
• False

What is the mass number of an atom that has 2 protons, 2 electrons and 4 neutrons?

• 4
• 6
• 8
• None of the choices

Which of the following is true regarding specific heat?

• Both of the statements are true
• Defined as the amount of heat needed to raise the temperature of 1 gram of the substance by 1K or 1°C
• No correct answer
• Defined as the amount of heat needed to raise the temperature of 1 mole of a substance by 1K or 1°C.

How many significant figures are in 5.070 x 103 g?

• 5
• 3
• 4
• 2

Given the percent composition by mass of all the elements in an unknown compound, we can always determine its molecular formula.

• True
• False

Positive ΔH means that heat is lost from the system into its surroundings, while negative enthalpy ΔH means that heat is absorbed by the system from its surroundings

• True
• False

Which of the following statement is true regarding atoms?

• Every atom does not have net electrical charge, thus the number of electrons and protons are equal in number.
• None of the choices
• Both protons and neutrons reside inside the atom's nucleus
• All of the given choices are correct
• Nucleus contains majority of the mass of an atom

Which gas law states that at constant pressure, the volume of a fixed amount of gas is directly proportional to its absolute temperature?

• Avogadro's Law
• Boyle's Law
• Charle's Law

Which of the following statement is correct?

• Molecular formula shows only the relative ratio of each of each atom in a molecule
• No correct answer
• Both of the given choices are correct
• Empirical formula shows the actual number of atoms in a molecule.

Resveratrol, C14H12O3 is a compound usually found in grapes and some berries. The molar mass of this compound is 228.26 g/mol. How many moles of resveratrol are in 600 grams of sample?

• 0.38 moles
• 5.26 moles
• 0.76 moles
• 2.63 moles

The percent composition by mass of ferrous sulfide, FeS, is 50% Fe and 50% S.

• True
• False

Using the periodic table, which element is in Group 4A period 6?

• Sn
• Ti
• V
• Pb

Which of the following can increase the pressure of a gas?

• Bigger container
• Smaller number of molecules
• Lower velocity
• Smaller container

Which of the following statement is true regarding the periodic table?

• Metalloids are elements that possess both metallic and non-metallic properties
• No correct answer
• Non-metals can be found on the upper right side of the periodic table
• Both of the given statements are correct

What is an example of endothermic process?

• Burning sugar
• Combustion of gasoline and burning sugar
• Ice melting and evaporating water
• Evaporating water
• Combustion of gasoline
• Ice melting

According to the kinetic molecular theory, average kinetic energy of gas molecules is proportional to absolute temperature. At any given temperature, gas molecules have exactly similar average kinetic energy.

• True
• False

What is the mass number of an atom that has 5 protons, 5 electrons and 6 neutrons?

• 16
• 10
• 11
• None of the choices

Which of the following statement is true regarding Dalton's atomic theory?

• Elements are made up of extremely tiny particles called atoms.
• Compounds are made up of a combination of atoms of more than one element
• All atoms of a given element are the same, but atoms of one element are different from the atoms of all other elements.
• All of the choices
• Atoms are can neither be created nor destroyed in a chemical reaction.

Compute the area given the following measurements: 2.0546 cm and 4.3 cm. Express the answer in significant figures.

• 8.8 cm2
• 8.8348 cm2
• 8.9 cm2
• 8.83 cm2