chem chapter 3 learn smart

Which of the following statements correctly describe the percent yield in a chemical reaction? Select all that apply.

% yield = actual yield ___________________________ × 100 theoreticalyield The actual yield is almost always less than the theoretical yield.

Which of the following steps are necessary to calculate the mass percent of oxygen in acetic acid (CH3COOH)? Select all that apply.

*Multiply the answer by 100 to find the mass percent of oxygen in acetic acid. -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. -Calculate the molar mass of acetic acid from its formula.

Correctly order the steps necessary to calculate the mass of product formed in a chemical reaction, given the masses of all reactants. Start with the first step at the top of the list.

- Determine the moles of each reactant present by dividing its mass by its molar mass - Determine the amount of product that could be formed from each reactant using the appropriate mole ratios - identify the limiting reactant as the reactant that produces the least amount of product - To find the mass, multiply the number of moles product formed (from the limiting reactant) by the molar mass of the product.

Which of the following statements describe combustion analysis correctly? Select all that apply.

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

Which items of information are necessary to calculate the mass percent of an element in a given compound? Select all that apply.

- The formula of the compound -The number of moles of the element in one mole of the compound -The molar mass of the compound

Given the balanced equation 2Al(s) + 3Cl2(g) → 2AlCl3(s), select all the conversion factors that correctly represent the molar relationships in this equation.

-2 mol AlCl3/3 mol Cl2 2 mol Al/3 mol Cl2

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

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

Which of the following statements correctly describe isomers? Select all that apply.

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

Which of the following statements correctly describe isomers? Select all that apply.

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

Which of the following statements correctly describe molar mass? Select all that apply.

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

Which of the following correctly reflect Avogadro's number? Choose all that apply.

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

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

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

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

1. write skeleton equation 2. balance the atoms 3. Adjust coefficients such that they are the smallest whole number. 4. Do final check to make sure the equation is balanced.

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

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 2 mol SO3 __________________________________ 3 mol O2

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

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

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

47.08%

Compound B2 (represented by the red spheres) reacts with AB, as shown in the illustration. From the illustration, the reagent in excess is _____, and the limiting reagent is _____.

B2; AB

Match each compound with its correct percent hydrogen by mass.

C6H6 7.74% CH3OH 12.6% CH2O 6.71%

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

CH2O, C6H12O6, C2H4O2

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

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.

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

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.

Formulas, amounts

Which of the following actions are permitted in balancing a chemical equation? Select all that apply.

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

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

Molar mass/ given mass

. 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

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.

Under certain conditions, the reaction of propane and water will produce carbon dioxide and hydrogen gas. The reaction may be represented as a two-step process: C3H8 (g) + 3H2O (g) → 3CO (g) + 7H2 (g) CO (g) + H2O (g) → CO2 (g) + H2 (g) Select the statements that correctly describe how to write a complete balanced equation for the overall process. Select all that apply.

The second equation must be multiplied by 3. The overall equation is given by C3H8 (g) + 6H2O (g) → 3CO2 (g) + 10H2 (g)

Match each type of reaction yield to the correct description.

Theoretical yield- The amount of product calculated from the molar ratio in the balanced chemical equation The amount of product calculated from the molar ratio in the balanced chemical equation Actual yield- Amount of product obtained experimentally from a chemical reaction Amount of product obtained experimentally from a chemical reaction Percent yield- actualyieldtheoreticalyield _________________________________________- x 100 actual yieldtheoretical yield

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

1. Write a skeleton equation. 2. Balance the atoms. 3. Adjust the coefficients such that they are the smallest whole-number coefficients. 4. Do a final check to make sure the equation is balanced.

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). Select all the statements that correctly describe how to write a complete balanced equation for the overall process.

-the overall equation is given by I2 (s) + 3Cl2(g)-->2ICl3(s) -the second equation must be multiplied by 2

The compounds depicted are ______ isomers because they have the same______ formula but have different _______formulas.

functional, molecular, structural

1.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.)

mol 40.08 mol

1.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.

mol, atoms

1.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