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31 Cards in this Set
- Front
- Back
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A mole of magnesium is best defined as
a. a certain volume of magnesium b. exactly one gram of magnesium c. a certain whole number of magnesium atoms d. a certain whole number of grams of magnesium |
C
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What is the percentage composition of CuCl2?
a. 65.50% Cu, 34.50% Cl b. 33% Cu, 66% Cl c. 47.267% Cu, 52.733% Cl d. 50% Cu, 50% Cl |
C
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If 0.500 mol of Na+ combines with 0.500 mol of Cl– to form NaCl, how many formula units of NaCl
are present? a. 3.01 × 1023 b. 6.02 × 1024 c. 6.02 × 1023 d. 1.00 |
A
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The molecular formula for vitamin C is C6H3O6. What is the empirical formula?
a. CH2O b. C3HO3 c. CHO d. C2HO2 |
D
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What is the percentage composition of CF4?
a. 16.8% C, 83.2% F b. 13.6% C, 86.4% F c. 81% C, 19% F d. 20% C, 80% F |
B
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The percentage of sulfur in SO2 is about 50%. What is the percentage of oxygen in this compound?
a. 50% b. 75% c. 90% d. 25% |
A
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What is the empirical formula for a compound that is 53.3% O and 46.7% Si?
a. SiO b. Si2O3 c. Si2O d. SiO2 |
D
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What is the molar mass of magnesium?
a. 22.990 g/mol b. 12.00 g/mol c. 24.305 amu d. 24.305 g/mol |
D
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The molar mass of an element is the mass of one
a. atom of the element. b. mole of the element. c. gram of the element. d. liter of the element. |
B
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A compound’s empirical formula is NO2. If the molar mass is 92 g/mol, what is the molecular
formula? a. N2O2 b. NO c. NO2 d. N2O4 |
D
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A formula that shows the simplest whole-number ratio of the atoms in a compound is the
a. ideal formula. b. molecular formula. c. empirical formula. d. structural formula. |
C
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What can be said about 1 mol Ag and 1 mol Au?
a. They have the same atomic mass. b. Their molar masses are equal. c. They contain the same number of atoms. d. They are equal in mass. |
C
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What is the empirical formula for a compound that is 43.6% phosphorus and 56.4% oxygen?
a. PO3 b. P3O7 c. P2O5 d. P2O3 |
C
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One mole of any element is equivalent to
a. 6.022 × 1023 atoms of that element. b. 6.022 × 1023 grams of that element. c. the mass number of atoms of that element. d. the atomic number of grams that element. |
A
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A molecular compound has the empirical formula XY3. Which of the following is a possible
molecular formula? a. XY3 b. X2Y5 c. X100Y299 d. X3Y |
A
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How many oxygen atoms are present in one formula unit of iron (III) sulfate, Fe2(SO4)3?
a. 3 b. 4 c. 17 d. 12 |
D
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The atomic mass of an element expressed in grams per mole is exactly the same as
a. moles per gram b. atomic mass units per mole c. atomic mass units per gram d. atomic mass units per atom |
D
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A compound contains 27.3 % carbon and 72.7 % oxygen. What is the empirical formula for this
compound? a. C2O b. CO c. C2O4 d. CO2 |
D
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A chemical formula includes the symbols of the elements in the compound and subscripts that
indicate a. the number of formula units present. b. the number of atoms or ions of each type. c. the formula mass. d. the charges on the elements or ions. |
B
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Changing a subscript in a correctly written chemical formula
a. changes the number of moles represented by the formula. b. changes the charges on the other ions in the compound. c. changes the formula so that it no longer represents that compound. d. has no effect on the formula. |
C
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What is the empirical formula for a compound that is 31.9% potassium, 28.9% chlorine, and
39.2% oxygen? a. KClO2 b. KClO3 c. K2Cl2O3 d. K2Cl2O5 |
B
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A compound contains 259.2 g of F and 40.8 g of C. What is the empirical formula for this
compound? a. CF4 b. C4F c. CF d. CF2 |
A
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A compound contains 64 g of O and 4 g of H. What is the empirical formula for this compound?
a. H2O b. H2O2 c. H4O4 d. HO |
D
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What is the empirical formula for a compound that is 36.1% Ca and 63.9% Cl?
a. CaCl b. Ca2Cl c. CaCl2 d. Ca2Cl2 |
C
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What is the percentage of OH– in Ca(OH)2?
a. 45.9% b. 66.6% c. 75% d. 90.1% |
A
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Rounded to the nearest tenth, what is the molar mass of barium nitrate, Ba(NO3)2?
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261.4 g/mol
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What is the mass in grams of 4.50 × 1012 atoms of lead? .
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1.55 x 10^-9 g
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How many formula units are present in a 312.0 gram sample of MgCl2? How many chloride ions are
in this sample? |
3.27 mol = 1.97 x 10^24 F.U.
3.94 x 10^24 chloride ions |
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The mass of 1 mol of gold atoms is 196.97 g. What is the mass of 1 atom of gold in atomic mass
units? (4 points) |
196.97 amu
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Calculate the percentage of oxygen in Fe2SiO4.
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64.00 g/mol
203.79 g/mol × 100=31.40%O |
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Calculate the percentage of aluminum in Al2O3.
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%Al=
53.96 g/mol 101.96 g/mol × 100=52.92%Al |
