CH 3
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
Balance the unbalanced equation given and match each substance to the correct coefficient as indicated.
1 6 2 3
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
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
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)
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 determine the amount identify to find the mass
Which of the following compounds has the largest molar mass?
H2SO4
Match each type of reaction yield to the correct description.
T- obtained A- Calculated P- Equation
Which one of the following options gives
given mass molar mass
The _____ formula of a compound is an integer multiple of the _____ formula
molecular; empirical
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 Avogadro's number
A chemical equation must be balanced. This means that the same _____ and _____ of atoms must appear on both sides of the equation.
number; type
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 tabl
Final amounts of reactants and products remaining after the reaction Initial amounts of reactants and products before reaction A balanced chemical equation Change in the amounts of reactants and products during the reaction
Which of the following statements correctly describe isomers?
Isomers are compounds with the same molecular formula. Isomers are compounds with the same empirical formula. Isomers are compounds with the same molar mass.
Which of the following statements correctly describe the percent yield in a chemical reaction? Select all that apply.
The actual yield is almost always less than the theoretical yield. % yield = actual yieldtheoretical yield × 100
Which of the following correctly reflect Avogadro's number? Choose all that apply.
The mole contains 6.022 x 1023 entities. The number of entities in a mole is called Avogadro's number.
Which of the following provides the correct mathematical operation to calculate the number of molecules in 2.0 mol of CH4?
2.0 mol × 6.022 × 1023 molecules/mol
1.52 × 1024 atoms of Au correspond to mol of Au atoms. Report your answer to 3 significant figures, using decimal notation (NOT scientific notation). (Avogadro's number is 6.022 × 1023.)
2.52
What is the mass percent of oxygen in aluminum oxide (Al2O3)?
47.08%
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.
Blank 1: formulas Blank 2: quantity
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.
Blank 1: mol Blank 2: atoms
The mass of a substance is the mass per mole of its entities, where the term "entities" can describe , ions, molecules, or formula units.
Blank 1: molar Blank 2: atoms
Correctly order the steps necessary to calculate the empirical formula of a compound, assuming that the masses of each element of the compound are provided. Start with the first step at the top of the list.
Calculate Write Divide IF Verify
In a limiting-reactant problem, the final quantities in a reaction table will show ______.
one of the reactants totally consumed (final amount is zero) the amount of the reactant in excess
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
The molecular formula of a compound having an empirical formula NH2 (ℳ = 32.05 g/mol) is
2 4
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.
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
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
Given the balanced equation 2Al(s) + 3Cl2(g) → 2AlCl3(s), select all the conversion factors that correctly represent the molar relationships in this equation.
2mol Al3mol Cl2 2mol AlCl33mol Cl2
Which of the following correctly reflects Avogadro's number?
6.022×1023entities/1mol
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%
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.
Blank 1: fraction
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.)
Blank 1: mol Blank 2: 40.08 Blank 3: mol
Correctly associate each molar mass with its compound.
CCl4 matches Choice, 153.8 g/mol 153.8 g/mol CH2O matches Choice, 30.03 g/mol 30.03 g/mol SF6 matches Choice, 146.1 g/mol 146.1 g/mol KrF2 matches Choice, 121.8 g/mol 121.8 g/mol
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.
Which of the following statements describe the information that can be gained from a balanced chemical equation?
The physical states of reactants and products, often. The identities of substances involved. The relative quantities (moles) of substances involved.
Which of the following choices describe the steps required to determine the empirical formula of a compound from the mass percent? Select all that apply
The ratio of atoms of each element must be a ratio of integer numbers. 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. The mass percentage of each element is converted to moles using the mass formula massmolar mass.
Which of the following options identify the correct coefficients required to balance the reaction illustrated? In the illustration, carbon is black and oxygen is red.
The reactant CO must have the coefficient 2. CO2 is a product and has the coefficient 2.
Correctly order the steps necessary to balance a chemical equation. Start with the first step at the top of the list.
Write Balance Adjust Do
Correctly order the steps necessary to balance a chemical equation. Start with the first step at the top of the list.
Write Balance Adjust Do
Which of the following steps would be required to convert between the masses of any two substances involved in the same chemical reaction? Select all that apply.
Write a conversion factor using the coefficients from the balanced equation, and convert to moles of the second substance. Write a balanced chemical equation for the reaction. Convert from the given mass to moles of the same substance.
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.
assume convert derive divide multiply
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
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 molar masses of any reactants for which a mass has been given. The reactant that produces the least amount of possible product is the limiting reactant. Calculate the amount of product that could be formed from each reactant.
Which of the following actions are permitted in balancing a chemical equation? Select all that apply.
Multiplying all coefficients by a common factor Inserting coefficients in front of formulas of reactants and products
Which of the following pieces of information is/are necessary to calculate the molar mass of a compound? Select all that apply.
The formula of the compound The atomic masses of each of the elements that make up the compound
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 molar mass of the compound The number of moles of the element in one mole of the compound
Which items of information are necessary to calculate the mass percent of an element in a given compound? Select all that apply.
The molar mass of the compound The formula of the compound The number of moles of the element in one mole of the compound
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:
The overall equation is given by C3H8 (g) + 6H2O (g) → 3CO2 (g) + 10H2 (g) The second equation must be multiplied by 3.
Iodine trichloride is produced in a two-step process, represented by the following balanced equations:
The overall equation is given by I2 (s) + 3Cl2 (g) → 2ICl3 (s). The second equation must be multiplied by 2.
One molecule of Br2 has a mass of amu; thus, one mole of Br2molecules 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.
Blank 1: 159.8 Blank 2: 159.8
The _______ gives the smallest whole number ratio of moles of each element in a compound. Therefore, multiple compounds may have it in common. Multiple choice question.
empirical formula
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 of the following steps are necessary to calculate the mass percent of oxygen in acetic acid (CH3COOH)? Select all that apply.
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. Multiply the answer by 100 to find the mass percent of oxygen in acetic acid. Calculate the molar mass of acetic acid from its formula.
Which of the following statements correctly describe the empirical formula for a compound? Select all that apply.
The empirical formula of a compound gives the smallest whole number ratio of atoms in a compound. Different compounds can have the same empirical formula.
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.
The MnCl2 produced is dissolved in water. HCl is a reactant in this equation.
Which of the following statements correctly describe molar mass? Select all that apply.
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. The molar mass of a substance is the mass per mole of its entities.
In order to calculate the overall % yield for a multistep process ___________.
multiply the individual % yields by each other
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
Place the steps in order for calculating the molar mass of nitrogen gas, starting with the first step at the top of the list.
Identify multiply Report
Correctly order the steps necessary to solve for the mass of a product, or second reactant required, given the mass of one of the reactants in a chemical process. Start with the first step at the top of the list.
write convert convert the moles
Given the balanced equation Ag2S(s) + 2HCl(aq) → 2AgCl(s) + H2S(g), determine the molesof HCl required and the mass of AgCl formed from the complete reaction of 18.3 g of Ag2S.
21.2 g of AgCl are formed. 0.148 mol HCl are required.
Which of the following statements correctly describe the information conveyed by the balanced equation 16Cu (s) + S8 (g) → 8Cu2S (s)? Select all that apply.
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. 16 moles of Cu react with 1 mole of S8 to form 8 moles of Cu2S.
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.
Blank 1: 4 Blank 2: 1.008 Blank 3: 12.01
The compounds depicted are isomers because they have the same formula but have different formulas.
Blank 1: constitutional Blank 2: molecular, Blank 3: structural
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
Hydrogen and nitrogen react to form ammonia according to the balanced equation 3H2 (g) + N2 (g) → 2NH3 (g). In a particular reaction vessel, 4.5 mol of H2 are reacted with 4.5 mol of N2. Which of the following options correctly describe how to complete the reaction table given? Select all that apply.
The final quantity of NH3 present is 3.0 mol. The change in moles of N2 (a) is equal to -1.5.
A compound has the empirical formula CH2O. What are the possible options for the molecular formula of this compound? Select all that apply.
CH2O C2H4O2 C6H12O6
Which step is INCORRECT to determine the molecular formula for a compound using combustion analysis data? Multiple choice question.
Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion.
Match each term with its correct definition.
Empirical formula matches The simplest whole-number ratio of moles of each element in a compound Molecular formula matches Choice, Actual number of atoms of each element in a molecule Structural formula matches Choice, Shows the relative placement and connections of atoms in a molecule Shows the relative placement and connections of atoms in a molecule
Given the balanced equation 3H2(g) + N2(g) → 2NH3(g), calculate the mass of NH3 produced by the complete reaction of 2.55 g of H2.
14.4
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.
5.57 × 10-2 mol of Cu 3.35 × 1022 atoms of Cu
The number of entities in a mole (to 4 significant figures) is equal to Blank 1Blank 1 s , Incorrect Unavailable multiplied by 10 to the power of Blank 2Blank 2 s , Incorrect Unavailable
Blank 1: 6.023 Blank 2: 23
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
Blank 1: grams Blank 2: 16.00
Correctly order the steps necessary to determine the molecular formula for a compound using combustion analysis data. Start with the first step at the top of the list.
Determine the massess determine the mass determine the number determine the molecular
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.
Hydrogen and oxygen react to form water according to the balanced equation 2H2 (g) + O2 (g) → 2H2O (l). In a particular reaction vessel, 2.2 mol of H2 are reacted with 2.2 mol of O2. Which of the following options correctly describe how to complete the reaction table given? Select all that apply.
The change in moles of H2 (a) is equal to -2.2. The change in moles of O2 (b) is equal to -1.1. Identify H2 as the limiting reactant.
