LearnSmart chapter 3

Which of the following statements correctly interpret the balanced chemical equation 4HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2H2O (g) + Cl2 (g)

HCl is a reactant in this equation. The MnCl2 produced is dissolved in water.

Which of the following statements correctly describe isomers?

Isomers are compounds with the same empirical formula. Isomers are compounds with the same molecular formula. Isomers are compounds with the same molar mass.

Which of the following statements correctly describe the molecular formula for a compound?

It is possible that the molecular formula for a compound is the same as its empirical formula. The molecular formula gives the actual number of each type of atom in a compound. A molecular formula may give little or no information about the structure of the compound.

What is the only additional information needed to calculate the empirical formula of a compound if the masses of each element of the compound are provided?

The molar mass of each element

Which of the following pieces of information is/are necessary to calculate the molar mass of a compound?

1. The atomic masses of each of the elements that make up the compound 2. The formula of the compound

Menthol (molar mass = 156.3 g/mol) is a compound of carbon, hydrogen, and oxygen. When 0.1595 g of menthol underwent a combustion analysis, 0.449 g of CO2 and 0.184 g of H2O were produced. Select all the statements that correctly interpret these data.

1. The mass of C present is 0.123 g. 2. There are 2.04 × 10-2 moles of H in the sample.

Which of the following statements correctly describe molar mass?

1. The molar mass of a substance is the mass per mole of its entities. 2. The periodic table can be used to calculate the molar mass of any substance. 3. When referring to the mass per mole of an entity, the term "entities" could refer to atoms, ions, molecules, or formula units.

B2 reacts with AB to form AB2 according to the balanced equation B2 + 2AB → 2AB2. If 1.5 moles of B2 are reacted with 1.5 moles of AB, the maximum amount of AB2 that can form is equal to _____ moles.

1.5

What is the mass of Cs present in 15.0 g of cesium acetate, formula CsCH3COO?

10.4 g

When hydrogen gas is passed over powdered iron(III) oxide, iron metal and water vapor are formed. Which of the following is the correct balanced equation for this process?

3H2(g) + Fe2O3(s) → 2Fe(s) + 3H2O(g)

A reaction is expected to produce 83.5 g of CaCO3. The percent yield is recorded as 62.5%. What is the actual mass of CaCO3 obtained?

52.2 g

Which of the following options correctly describe the symbols used to write a balanced equation?

A liquid is indicated by the symbol (l). The symbol (g) indicates a substance in the gas phase.

Combustion analysis of a 0.3756 g sample containing only C and H yields 1.1385 g of CO2 and 0.5805 g of H2O. What is the molecular formula given its molar mass is 58.12 g/mol?

C4H10

Which of the following statements correctly describe the steps used to determine which reactant in a given reaction is limiting?

Calculate the amount of product that could be formed from each reactant. The reactant that produces the least amount of possible product is the limiting reactant. Calculate the molar masses of any reactants for which a mass has been given.

The _______ gives the smallest whole number ratio of moles of each element in a compound. Therefore, multiple compounds may have it in common.

empirical formula

The _____ formula of a compound is an integer multiple of the _____ formula.

molecular; empirical

Which one of the following options gives the correct procedure to calculate the mass of a substance given the number of moles?

moles x molar mass

A chemical equation must be balanced. This means that the same _____ and _____ of atoms must appear on both sides of the equation.

number; type

Correctly associate each molar mass with its compound.

on phone

Which of the following provides the correct mathematical operation to calculate the number of molecules in 2.0 mol of CH4?

on phone

Which one of the following options gives the correct procedure to calculate the number of moles of a substance given the mass?

on phone

1.52 × 1024 atoms of Au correspond to _____________ mol

2.52

What is the mass percent of oxygen in aluminum oxide (Al2O3)?

47.08%

Which convention is used in this textbook for rounding off atomic masses based on the periodic table?

Atomic masses are rounded to 4 significant figures.

Which of the following compounds has the largest molar mass?

H2SO4

Which of the following provides the correct mathematical operation to convert the number of atoms of a sample to the number of moles?

number of atoms/ Avogardos number

Arrange the necessary steps in order for finding the molecular formula of an unknown compound from mass percent data. Place the first step at the top of the list.

on phone

Place the following calculations in the correct order to determine the molar mass of H2SO4. Start with the first step at the top of the list.

on phone

Which step is INCORRECT to determine the molecular formula for a compound using combustion analysis data?

Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion.

Combustion analysis is commonly used to determine the empirical formula of unknown compounds containing principally C and H. For a compound containing C, H, and O only, which of the following statements is INCORRECT?

The amount of oxygen is determined from the mass of H2O produced.

The molecular mass (or formula mass) of a compound expressed in amu is numerically the same as the mass of one ___________ of the compound expressed in grams.

mole

n order to calculate the overall % yield for a multistep process ___________.

multiply the individual % yields by each other

Correctly order the steps necessary to balance a chemical equation. Start with the first step at the top of the list.

on phone

Which of the following actions are permitted in balancing a chemical equation?

Multiplying all coefficients by a common factor Inserting coefficients in front of formulas of reactants and products

True or false: In order to balance the reaction of hydrogen gas (H2) with oxygen gas (O2) to form liquid water (H2O), a student adds a subscript of 2 after the oxygen in H2O. This is an acceptable method of balancing the above reaction.

false

Which items of information are necessary to calculate the mass percent of an element in a given compound?

1. The number of moles of the element in one mole of the compound 2. The formula of the compound 3. The molar mass of the compound

Which of the following statements correctly describe CH3COOH (acetic acid)? Select all that apply.

1. There are 4 moles of hydrogen atoms per mole of acetic acid. 2.There are 2 atoms of carbon in one molecule of acetic acid.

Place the steps in order for calculating the molar mass of nitrogen gas, starting with the first step at the top of the list.

1. identify 2. multiply 3. repeat

The balanced equation 2S(s) + 3O2(g) → 2SO3 (g) is given. The number of moles of SO3 that will form from the complete reaction of 1.5 mol of O2 is given by _____.

1.5 mol O2 x 2mol SO33mol O2

Which of the following statements correctly describe the information conveyed by the balanced equation 16Cu (s) + S8 (g) → 8Cu2S (s)?

16 moles of Cu react with 1 mole of S8 to form 8 moles of Cu2S. Cu and S8 are reactants and Cu2S is the product. 16 atoms of Cu react with 1 molecule of S8 to form 8 formula units of Cu2S.

Calculate the correct number of moles AND formula units in 7.3 x 10-3 g of CaSO4. Avogadro's number is 6.022 x 1023.

1. 3.2 x 1019 formula units of CaSO4 2. 5.4 x 10-5 moles of CaSO4

Which of the following steps would be required to convert between the masses of any two substances involved in the same chemical reaction?

1. Convert from the given mass to moles of the same substance. 2. Write a conversion factor using the coefficients from the balanced equation, and convert to moles of the second substance. 3. Write a balanced chemical equation for the reaction.

The ____________ mass of a substance is the mass per mole of its entities, where the term "entities" can describe _____________, ions, molecules, or formula units.

molar;atoms

The molar mass of a monatomic element is the numerical value listed on the periodic table expressed in units of g/__________. For example, the molar mass of calcium (Ca) is __________ with units of g/___________. (Remember to round to 4 significant digits.) Listen to the complete question

mole;40.08;mole

n a limiting-reactant problem, the final quantities in a reaction table will show ______.

the amount of the reactant in excess one of the reactants totally consumed (final amount is zero)

The mole relates the atomic mass of an element expressed in amu with the mass of 1 mole of that element expressed in____________-. The mass of 1 mole of oxygen atoms is therefore equal to _____________ g (to 4 significant figures). Use the periodic table given in this book to answer this question correctly.

grams;16.00

One formula unit of KOH has a mass of _________ amu; hence, 1 mol of KOH has a mass of___________ g. (Remember to read atomic masses to 4 significant figures before adding them together.)

56.11;56.11

What is the empirical formula of a hydrocarbon containing 79.9% carbon by mass?

CH3

What is the empirical formula of a compound that consists of 0.039 moles of iron atoms combined with 0.052 moles of oxygen atoms?

Fe3O4

A useful method for keeping track of quantities in a chemical reaction is a reaction table. Which of the following are components of a reaction table? Select all that apply.

Initial amounts of reactants and products before reaction A balanced chemical equation Final amounts of reactants and products remaining after the reaction Change in the amounts of reactants and products during the reaction

Which of the following options give the correct number of moles AND the correct number of atoms in a 3.54-g sample of copper (Cu)? Avogadro's number is 6.022 × 1023. Select both correct answers.

on phone

Which of the following steps are necessary to calculate the mass percent of oxygen in acetic acid (CH3COOH)?

1. Multiply the answer by 100 to find the mass percent of oxygen in acetic acid. 2. Calculate the molar mass of acetic acid from its formula. 3. Multiply the moles of oxygen in the molecular formula by the molar mass of oxygen and then divide by the mass of one mole of acetic acid.

The molecular formula of a compound having an empirical formula NH2 (ℳ = 32.05 g/mol) is N___________ H ____________.

2;4

A nitrogen oxide contains 30.45% N mass. If the molar mass of the compound is 90. ± 5 g/mol, what is its molecular formula?

N2O4

Iodine trichloride is produced in a two-step process, represented by the following balanced equations: I2 (s) + Cl2 (g) → 2ICl (s)I2 (s) + Cl2 (g) → 2ICl (s); and ICl (s) + Cl2 (g) → ICl3 (s)ICl (s) + Cl2 (g) → ICl3 (s).

The overall equation is given by I2 (s) + 3Cl2 (g) → 2ICl3 (s)I2 (s) + 3Cl2 (g) → 2ICl3 (s). The second equation must be multiplied by 2.

Molecular formulas ______.

give the actual number of each element in a compound

Which of the following correctly reflect Avogadro's number?

1. The number of entities in a mole is called Avogadro's number. 2. The mole contains 6.022 x 1023 entities.

What is the mass of nitrogen in 43.7 g of ammonium carbonate, (NH4)2CO3?

12.7 g

The mass % of Ca in CaSO4 is 29.45%. To calculate the mass of Ca present in a 25.6-g sample of this compound, the correct procedure is given by _____.

29.45/100 x 25.6

The number of entities in a mole (to 4 significant figures) is equal to ____________ multiplied by 10 to the power of ___________ and is called Avogadro's number..

6.022;23

Which of the following correctly reflects Avogadro's number?

6.022x10 exponent 23 entities / 1 mole

How many grams of KMnO4 correspond to 3.13 x 1022 formula units of KMnO4? Avogadro's number is 6.022 x 1023.

8.21 g of KMnO4

A particular reaction is expected to yield 125 g of calcium. The actual amount of calcium obtained is equal to 105 g. Calculate the percentage yield for the reaction.

84.0%

A compound has the empirical formula CH2O. What are the possible options for the molecular formula of this compound?

CH2O C2H4O2 C6H12O6

The __________ is the SI unit that expresses the amount of substance. Specifically, it is defined as the amount of substance containing the same number of entities as the number of ___________ in exactly 12 g of carbon-12.

Mole;atoms

In order to calculate the mass of an element in a given sample of a compound, the mass of the compound is multiplied by the mass _____________ of the element in the compound.

ratio

True or false: To calculate the overall percent yield for a multistep process, add the individual percent yields together.

false

A chemical equation is a statement using chemical __________ that expresses both the identities and the relative __________ of the reactants and products involved in a chemical or physical change. Listen to the complete question

formulas;quantity

Atomic masses are commonly read from the periodic table to _________ significant figures. The atomic mass of H is therefore equal to __________ amu, whereas the atomic mass of C is equal to ___________ amu. Use the periodic table given in your textbook to answer the question.

four;1.008;12.01

Match each term with its correct definition.

1. Empirical formula- The simplest whole-number ratio of moles of each element in a compound 2. Molecular formula- Actual number of atoms of each element in a molecule 3. Structural formula- Shows the relative placement and connections of atoms in a molecule

Which of the following statements describe combustion analysis correctly?

1. Every 1 mole of carbon in the compound will produce 1 mole of CO2. 2. The mass of hydrogen in the compound is determined from the amount of H2O produced. 3. Combustion analysis involves burning a compound in O2.

Which of the following choices describe the steps required to determine the empirical formula of a compound from the mass percent?

1. The mass percentage of each element is converted to moles using the mass formula massmolar massmassmolar mass. 2. The ratio of atoms of each element must be a ratio of integer numbers. 3. If a compound contains 52% of mass of C, it can be assumed that there are 52 g of C in 100 g of the compound.

Which of the following statements describe the information that can be gained from a balanced chemical equation?

1. The relative quantities (moles) of substances involved. 2. The physical states of reactants and products, often. 3. The identities of substances involved.

One molecule of Br2 has a mass of _________ amu; thus, one mole of Br2 molecules has a mass of _________ grams. (Remember to round off atomic masses to 4 significant digits.) Use the periodic table furnished in your book to answer this question correctly.

159.8;159.8

Identify the whole number coefficients required to balance the chemical equation SO2(g) + O2(g) → SO3(g) correctly. (Enter ALL numbers, including the digit 1 if required, and make sure you have the simplest ratio of coefficients.)

2;1;2

Which of the following statements correctly describe the empirical formula for a compound?

1. Different compounds can have the same empirical formula. 2. The empirical formula of a compound gives the smallest whole number ratio of atoms in a compound.