SmartBook Ch. 3 Pt. 1
Which of the following steps are necessary to calculate the mass percent of oxygen in acetic acid (CH3COOH)? Select all that apply. a) Determine the number of molecules of acetic acid in the sample b) Multiply the answer by 100 to find the mass percent of oxygen in acetic acid. c) Calculate the molar mass of acetic acid from its formula. d) 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.
b) Multiply the answer by 100 to find the mass percent of oxygen in acetic acid. c) Calculate the molar mass of acetic acid from its formula. d) 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.
Which of the following pieces of information is/are necessary to calculate the molar mass of a compound? Select all that apply. a) The mass of a sample of the compound b) The atomic masses of each of the elements that make up the compound c) The formula of the compound d) The physical properties of the compound
b) The atomic masses of each of the elements that make up the compound c) The formula of the compound
Correctly associate each molar mass with its compound. 1) CCl4 2) CH2O 3) SF6 4) KrF2 a) 30.03 g/mol b) 153.8 g/mol c) 121.8 g/mol d) 146.1 g/mol
b, a, d, c
Match each compound with its correct percent hydrogen by mass. 1) C6H6 2) CH3OH 3) CH2O a) 6.71% b) 7.74% c) 12.6%
b, c, a
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. a) ℳ of H2SO4 = 98.09 g/mol b) ℳ of H2SO4 = (2 × ℳ of H) + (ℳ of S) + (4 × ℳ of O) c) ℳ of H2SO4 = (2 × 1.008 g/mol) + (32.07 g/mol) + (4 × 16.00 g/mol)
b, c, a
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 _____. a) (25.6 / 29.45) x 100 b) 29.45 x 25.6 c) (29.45 / 100) x 25.6 d) (29.45 / 25.6) x 100
c) (29.45 / 100) x 25.6
What is the mass of Cs present in 15.0 g of cesium acetate, formula CsCH3COO? a) 0.113 g b) 1.88 g c) 10.4 g d) 0.693 g
c) 10.4 g
What is the mass of nitrogen in 43.7 g of ammonium carbonate, (NH4)2CO3? a) 6.37 g b) 25.5 g c) 12.7 g d) 43.7 g
c) 12.7 g
What is the mass percent of oxygen in aluminum oxide (Al2O3)? a) 5.69% b) 29.72% c) 47.08% d) 88.95%
c) 47.08%
How many grams of KMnO4 correspond to 3.13 x 10^22 formula units of KMnO4? Avogadro's number is 6.022 x 10^23. a) 0.0520 g of KMnO4 b) 158 g of KMnO4 c) 8.21 g of KMnO4 d) 3.29 x 10^-4 g KMnO4
c) 8.21 g of KMnO4
Which of the following compounds has the largest molar mass? a) C6H6 b) CH2Cl2 c) H2SO4 d) SO2
c) H2SO4
Which of the following correctly reflect Avogadro's number? Choose all that apply. a) The mole is abbreviated mo. b) For a pure substance, the mole specifies only the number of entities in a sample. c) The mole contains 6.022 x 1023 entities. d) The number of entities in a mole is called Avogadro's number.
c) The mole contains 6.022 x 1023 entities. d) The number of entities in a mole is called Avogadro's number.
Which one of the following options gives the correct procedure to calculate the number of moles of a substance given the mass? a) molar mass/given mass b) given mass × molar mass c) given mass/molar mass
c) given mass/molar mass
Which one of the following options gives the correct procedure to calculate the mass of a substance given the number of moles? a) moles / molar mass b) molar mass / moles c) moles x molar mass
c) moles x molar mass
Which of the following provides the correct mathematical operation to convert the number of atoms of a sample to the number of moles? a) Avogadro's number / number of atoms b) number of atoms × Avogadro's number c) number of atoms / Avogadro's number
c) number of atoms / Avogadro's number
Match each compound to the correct description of its composition. 1) CHCl3 2) CH2Cl2 3) CCl4 a) 1 mole of this substance contains 12.01 g of carbon, 2.016 g of hydrogen, and 70.90 g of chlorine. b) 1 mole of this substance contains 1 mole of carbon and 4 moles of chlorine. c) This molecule contains 12.01 amu of carbon, 1.008 amu of hydrogen, and 106.35 amu of chlorine.
c, a, b
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
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
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 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
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
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.)
159.8, 159.8
1.52 × 10^24 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
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.
4, 1.008, 12.01
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
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
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 10^23. a) 3.2 x 10^19 formula units of CaSO4 b) 8.9 x 10^-29 formula units of CaSO4 c) 9.9 x 10^-1 moles of CaSO4 d) 5.4 x 10^-5 moles of CaSO4
a) 3.2 x 10^19 formula units of CaSO4 d) 5.4 x 10^-5 moles of CaSO4
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 × 10^23. Select both correct answers. a) 3.35 × 10^22 atoms of Cu b) 5.57 × 10^-2 mol of Cu c) 9.25 × 10^-26 atoms of Cu d) 2.25 × 10^2 mol of Cu
a) 3.35 × 10^22 atoms of Cu b) 5.57 × 10^-2 mol of Cu
Which of the following correctly reflects Avogadro's number? a) 6.022×10^23 entities/1 mol b) 6.022 × 10^23 entities x 1 mol c) 6.022×10^23 entities/1 g d) 6.022×10^23 entities/1 amu
a) 6.022×10^23 entities/1 mol
Which convention is used in this textbook for rounding off atomic masses based on the periodic table? a) Atomic masses are rounded to 4 significant figures. b) Atomic masses are rounded to 1 decimal place. c) Atomic masses are rounded to 2 decimal places. d) Atomic masses are used as expressed in the periodic table, with no rounding. e) Atomic masses are rounded to 3 significant figures.
a) Atomic masses are rounded to 4 significant figures.
Which items of information are necessary to calculate the mass percent of an element in a given compound? Select all that apply. a) The molar mass of the compound b) The number of moles of the element in one mole of the compound c) The formula of the compound d) The number of molecules/formula units of the compound e) The mass of the compound
a) The molar mass of the compound b) The number of moles of the element in one mole of the compound c) The formula of the compound
Which of the following statements correctly describe CH3COOH (acetic acid)? Select all that apply. a) There are 4 moles of hydrogen atoms per mole of acetic acid. b) The molar mass of acetic acid is 29.02 g/mol. c) There are 2 atoms of carbon in one molecule of acetic acid. d) There are 16.00 amu of oxygen per molecule of acetic acid.
a) There are 4 moles of hydrogen atoms per mole of acetic acid. c) There are 2 atoms of carbon in one molecule of acetic acid.
Which of the following statements correctly describe molar mass? Select all that apply. a) When referring to the mass per mole of an entity, the term "entities" could refer to atoms, ions, molecules, or formula units. b) The periodic table can be used to calculate the molar mass of any substance. c) The molar mass is commonly given in units of kg/mol. d) The term "molar mass" applies to compounds but not to elements. e) The molar mass of a substance is the mass per mole of its entities.
a) When referring to the mass per mole of an entity, the term "entities" could refer to atoms, ions, molecules, or formula units. b) The periodic table can be used to calculate the molar mass of any substance. e) The molar mass of a substance is the mass per mole of its entities.
Place the steps in order for calculating the molar mass of nitrogen gas, starting with the first step at the top of the list. a) Identify that nitrogen exists as N2 and find the atomic mass of nitrogen on the periodic table. b) Report the molar mass of nitrogen as 28.02 g/mol. c) Multiply the atomic mass of nitrogen by 2 in order to calculate its molecular mass.
a, c, b
Which of the following provides the correct mathematical operation to calculate the number of molecules in 2.0 mol of CH4? a) 2.0 mol/6.022×10^23molecules/mol b) 2.0 mol × 6.022 × 10^23 molecules/mol c) 6.022×10^23 molecules/mol/2.0 mol c) 1/2.0mol×6.022×1023 molecules
b) 2.0 mol × 6.022 × 10^23 molecules/mol
Which of the following provides the correct mathematical operation to calculate the number of molecules in 2.0 mol of CH4? a) 2.0 mol / 6.022×10^ 23 b) 2.0 mol × 6.022×10^23 molecules/mol c) 1 / 2.0 mol × 6.022×10^23 molecules d) 6.022×10^23 molecules/mol / 2.0 mol
b) 2.0 mol × 6.022×10^23 molecules/mol
