Chemical Formulas & Equations (Test 12/9)
Which quantity is equivalent to 39g of LiF? (1) 0.50 mol (2) 1.0 mol (3) 1.5 mol (4) 2.0 mol
(3) 1.5 mol
What is the mass if 0.50 mol of CuSO4 * 5H2O? (1) 47.8 g (2) 95.6 g (3) 125 g (4) 250 g
(3) 125 g
Which is an empirical formula? (1) C2H2 (2) C2H4 (3) Al2Cl6 (4) K2O
(4) K2O
How many metallic elements are present in the formula NaKSO4?
Two metallic elements
What is the total number of sulfur atoms in the formula (NH4)2SO4? (1) 1 (2) 2 (3) 3 (4) 4
(1) 1
What is the molarity of 1.5 liters of an aqueous solution that contains 52 grams of lithium fluoride, LiF, (gram-formula mass = 26 grams/mole)? (1) 1.3 M (2) 2.0 M (3) 3.0 M (4) 0.75 M
(1) 1.3 M
What is the concentration of a solution, in parts per million, if 0.02 grams of Na3PO4 is dissolved in 1000 grams of water? (1) 20 ppm (2) ppm (3) 0.2 ppm (4) 0.02 ppm
(1) 2.0 ppm
Consider the following unbalanced equation. Ag + H2S = Ag2S + H2 What is the sum of the coefficients when the equation is completely balanced using the smallest whole-number coefficients? (1) 5 (2) 8 (3) 10 (4) 4
(1) 5
Consider the following unbalanced equation. C3H8 (g) + O2 (g) = H2O (g) + CO2 (g) When the equation is completely balanced using smallest whole numbers, the coefficient of O2 is (1) 5 (2) 2 (3) 3 (4) 7
(1) 5
A 24.00 gram sample of an aqueous solution contains 0.012 grams of NH3. What is the concentration of NH3 in the solution, expressed as parts per million? (1) 5.0 ppm (2) 15 ppm (3) 20. ppm (4) 50. ppm
(1) 5.0 ppm
When the equation Al(s) + O2 (g) = Al2O3(s) is correctly balanced using smallest whole numbers, the sum of the coefficients will be (1) 9 (2) 7 (3) 3 (4) 12
(1) 9
When the equation Al2(SO4)3 + ZnCL2 = AlCl3 + ZnSO4 is correctly balanced using the smallest whole numbers. the sum of the coefficient is (1) 9 (2) 8 (3) 5 (4) 4
(1) 9
The empirical formula of a compound is CH4. The molecular formula of the compound could be (1) CH4 (2) C2H6 (3) C3H8 (4) C4H10
(1) CH4
In a sample of solid Ba(NO3)2 the ratio of barium ions to nitrate ions is (1) 1:3:2 (2) 1:2 (3) 2:1 (4) 1:6
(2) 1:2
Consider the following unbalanced equation. C8H16(g) + O2(g) = H2O(g) +CO2(g) When the equation is completely balanced using the smallest whole numbers, the coefficient of CO2 is (1) 1 (2) 2 (3) 12 (4) 16
(2) 2
Consider the following unbalanced equation. FeCl2 + Na2CO3 = FeCO3 + NaCl When the equation is completely balanced using the smallest whole numbers, the coefficient of NaCl is (1) 6 (2) 2 (3) 3 (4) 4
(2) 2
Consider the following unbalanced equation. N2(g) + O2(g) = N2O5(g) When the equation is completely balanced using smallest whole numbers, the coefficient of N2(g) is (1) 1 (2) 2 (3) 5 (4) 4
(2) 2
What is the molarity of a solution that contains 0.50 mole of NaOH in 0.25 liter of solution? (1) 1.0 M (2) 2.0 M (3) 0.25 M (4) 0.50 M
(2) 2.0 M
What is the percent by mass of carbon in CO2? (1) 12% (2) 27% (3) 44% (4) 73%
(2) 27%
What is the percent by mass of sulfur in Fe2O3? The formula mass of F2O3 = 160 amu. (1) 16% (2) 30% (3) 46% (4) 70%
(2) 30%
What is the total number of hydrogen atoms in the formula 3Mg(C2H3O2)2? (1) 3 (2) 6 (3) 12 (4) 18
(2) 6
Consider the following unbalanced equation. Ca(OH)2 + (NH4)2SO4 = CaSO4 + NH3 + H2O What is the sum of the coefficients when the equation is completely balanced using the smallest whole-number coefficients? (1) 5 (2) 7 (3) 9 (4) 11
(2) 7
A compound with an empirical formula of CH2 has a molecular mass of 70 amu. What is its molecular formula? (1) CH2 (2) C2H4 (3) C2H8 (4) C5H10
(2) C5H10
Which compound has the same empirical and molecular formula? (1) H2O2 (2) NH3 (3) C2H6 (4) Hg2Cl2
(2) NH3
Molarity is defined as the (1) moles of solute per kilogram of solvent (2) moles of solute per liter of solution (3) mass of a solution (4) volume of a solvent
(2) moles of solute per liter of solution
Pure nitrogen combines directly with an active metal to form a (1) nitrate (2) nitride (3) nitrite (4) permanganate
(2) nitride
The concentration of a solution can be expressed in (1) milliliters per minute (2) parts per million (3) grams per kelvin (4) joules per gram
(2) parts per million
Which type of concentration is calculated when the grams of solute is divided by the grams of the solution and the result is multiplied by 1000000? (1) molarity (2) parts per million (3) percent by mass (4) percent by volume
(2) parts per million
What is the gram formula mass of (NH4)3PO4? (1) 112 g/mol (2) 121 g/mol (3) 149 g/mol (4) 242 g/mol
(3) 149 g/mol
In a sample of solid Al(NO3)3, the ratio of aluminum ions to nitrate ios is (1) 1:1 (2) 1:2 (3) 1:3 (4) 1:6
(3) 1:3
A 3.0 M HCl(aq) solution contains a total of (1) 3.0 grams of HCl per liter of water (2) 3.0 grams of HCl per mole of solution (3) 3.0 moles of HCl per liter of solution (4) 3.0 moles of HCl per mole of water
(3) 3.0 moles of HCl per liter of solution
In a sample of calcium phosphate Ca3(PO4)2, the ratio of calcium ions to phopshate ions is (1) 1:1 (2) 2:3 (3) 3:2 (4) 3:4
(3) 3:2
The empirical formula of a compound is CH2. The molceular formula of this compound could be (1) CH4 (2) C2H2 (3) C2H4 (4) C3H3
(3) C2H4
Which chemical formula represents a compound? (1) Ca (2) Cr (3) CO (4) Co
(3) CO
Which species contains the greatest percent by mass of hydrogen? (1) OH (2) H2O (3) H3O (4) H2O2
(3) H3O
What is the total number of atoms in NH4(SO4)2? (1) 10 (2) 11 (3) 14 (4) 15
(4) 15
What is the total number of atoms of oxygen in the formula Al(ClO3)3 * 6H2O? (1) 6 (2) 9 (3) 10 (4) 15
(4) 15
What is the gram-formula mass of Fe(NO3)3? (1) 146 g/mol (2) 194 g/mol (3) 214 g/mol (4) 242 g/mol
(4) 242 g/mol
How many moles are in 168 g of KOH? (gram formula mass = 56 g) (1) 0.3 mol (2) 0.5 mol (3) 1.0 mol (4) 3.0 mol
(4) 3.0 mol
What is the concentracion of a solution in parts per million, if 0.089 gram of NaCl is dissolved in 2.50 grams of water? (1) 0.03 ppm (2) 0.27 ppm (3) 35.6 ppm (4) 356 ppm
(4) 356 ppm
What is the total mass of 0.75 mol of SO2? (1) 16 g (2) 24 g (3) 32 g (4) 48 g
(4) 48 g
Consider the following unbalanced equation Li + N2 = Li3N When the equation is competely balanced using smallest whole numbers, the coefficient of lithium is (1) 1 (2) 2 (3) 3 (4) 6
(4) 6
What is the total number of oxygen atoms present in one unit of Mg(ClO3)2? (1) 5 (2) 2 (3) 3 (4) 6
(4) 6
What is the gram formula mass of Ca(OH)2? (1) 29 g (2) 34 g (3) 56 g (4) 74 g
(4) 74 g
What is the total number of moles of NaCl(s) needed to make 3.0 liters of a 2.0 M NaCl solution? (1) 1.0 mol (2) 0.70 mol (3) 6.0 mol (4) 8.0 mol
(4) 8.0 mol
What is the total number of atoms in the formula Ca(NO3)2? (1) 7 (2) 2 (3) 3 (4) 9
(4) 9
A compound has an empirical of CH and a molecular mass of 78 amu. What is the molecular formula of the compound? (1) C2H2 (2) C3H3 (3) C4H4 (4) C6H6
(4) C6H6
What is the empirical formula of a compound with the molecular formula C6H12O6? (1) C4H8O4 (2) C3H6O3 (3) C2H4O2 (4) CH2O
(4) CH2O
An example of an empirical formula is (1) S2H2 (2) H2O2 (3) C2Cl2 (4) CaCl2
(4) CaCl2
Which substance has the greatest molecular mass? (1) H2O2 (2) NO (3) CF4 (4) I2
(4) I2
A chemical formula is an expression used to represent (1) mixtures only (2) elements only (3) compounds only (4) elements and compounds
(4) elements and compounds
A student is instructed to make 0.250 liter of a 0.200 M aqueous solution of Ca(NO3)2. a) Show a correct numerical setup for calculating the total number of moles of Ca(NO3)2 needed to make 0.250 liter of the 0.200 M calcium nitrate solution. b) In order to prepare the described solution in the lab, two quantities must be measured accurately. One of these quantities is the volume of the solution. What other quantity must be measured to prepare this solution?
(a) 0.2 = x/(0.25) x = (0.250 L)((0.200 mol)/(1 L)) (b) mass of Ca(NO3)2; to prepare a solution of given molarity, the number of moles of solute must be measured in addition to the volume of the solution
For each of the following formulas, write the name of each element and the number of atoms of that element are in the formula. (a) K3PO4 (b) 3Al(OH)3 (c) 5Fe2(SO4)3
(a) 3 potassium, 1 phosphorus, 4 oxygen (b) 1 aluminum, 3 oxygen, 3 hydrogen (c) 2 iron, 3 sulfur, 12 oxygen
For each of the following formulas, write the name of each element and the number of atoms of that element that are in the formula. (a) 2K2PO4 (b) 3Al(OH3) (c) 5Fe2(SO4)3
(a) 6 potassium, 2 phosphorus, 8 oxygen (b) 3 aluminum, 9 oxygen, 9 hydrogen (c) 10 iron, 15 sulfur, 60 oxygen
Write the correct formulas for the following binary molecular compounds. (a) carbon monoxide (b) boron tribromide (c) sulfur hexafluoride (d) carbon dioxide (e) carbon tetrabromide (f) nitrogen dioxide
(a) CO (b) BBr3 (c) SF6 (d) CO2 (e) CBr4 (f) NO2
Write the formulas for each of the following compounds. (a) iron (II) oxide (b) tin (II) sulfide (c) copper (I) chloride (d) mercury (II) iodide (e) lead (II) nitrate (f) iron (III) oxide
(a) FeO (b) SnS (c) CuCl (d) HgI2 (e) Pb(NO3)2 (f) Fe2O3
Write the correct formulas for the following binary ionic compounds. (a) lithium fluoride (b) calcium oxide (c) aluminum nitride (d) carbon dioxide (e) potassium iodide (f) aluminum oxide
(a) LiF (b) CaO (c) AIN (d) CO2 (e) KI (f) Al2O3
For the following, write a balanced chemical equation to show how the ions would combine in a double replacement equation. (a) sodium bromide and silver nitrate form sodium nitrate and silver bromide (b) potassium carbonate and calcium nitrate form potassium nitrate and calcium carbonate (c) ammonium sulfate and barium chloride form ammonium chloride and barium sulfate (d) barium nitrate and potassium chromate form barium chromate and potassium nitrate
(a) NaBr + AgNO3 = NaNO3 + AgBr (b) K3CO3 + Ca(NO3)2 = 2KNO3 + CaCO3 (c) Ba(NO3)2 + BaCl2 = 2NH2Cl + BaSO4 (d) 2NaOH + CaCl2 = 2NaCl + 2KNO3
A total of 1.4 moles of sodium nitrate is dissolved in enogh water to make 2.0 liters of an aqueous solution. The gram-formula mass of sodium nitrate is 85 grams/mol. (a) Write the chemical formula for the solute. (b) Show a numerical setup for calculating the mass of the solute used to make the solution. (c) Compare the boiling point of the solution at standard pressure to the boiling point of H2O at standard pressure. (d) Determine the molarity of the solution.
(a) NaNO3 (b) (85 g/mol)(1.4 mol) (c) H2O boils at a lower temperature. (d) 0.70 M
Write the correct formulas for the following compounds that contain polyatomic ions. (a) sodium hydroxide (b) potassium nitrate (c) magnesium sulfate (d) aluminum phosphate (e) aluminum nitrate (f) ammonium nitrate
(a) NaOH (b) KNO3 (c) MgSO4 (d) AlPO4 (e) NH4NO3
Name each of the following compounds. (a) Ca(NO3)2 (b) KOH (c) MgCO3 (d) Na3PO4 (e) LiNO3 (f) Mg(C2H3O2)2
(a) calcium nitrate (b) potassium hydroxide (c) magnesium carbonate (d) sodium phospate (e) lithium nitrate (f) magnesium acetate
Name each of the following binary molecular compounds. (a) O2F2 (b) SiF4 (c) S4N4 (d) Sf2 (e) H2S (f) P4O10
(a) dioxygen difluoride (b) silicon tetrafluoride (c) tetrasulfur tetranitride (d) sulfure difluoride (e) dihydrogen sulfide (f) tetraphosphorus decaoxide
A compound has an empirical formula of CH2 and a molecular mass of 56 amu. What is its molecular formla?
C4H8
What incorrect information is given by the formula MgOH2, instead of the correct formula, Mg(OH)2?
MgOH2 does not show that there are two hydroxide ions. It states that there is only one oxygen atom, and there should be two.
More than 60 parts per million of dissolved minerals is considered to be hard water. A 750 gram sample of water contains 0.04 gram of minerals. Would this sample be considered hard water? Explain.
No because the mas of the solute in minerals is 0.04 grams and the mass of the solution is 750 grams. There is only 53 parts per million dissolved in the solution; this amount is under the limit.
What is the qualitative and quantitative information given by the formula Ca3(PO4)2?
Qualitative information: the compound is made of calcium, phosphorus, and oxygen; phosphorus and oxygen are combined to form the polyatomic phosphate ion. Quantitative information: one unit of the compound contains three calcium atoms and two phosphate ions. Each phopsphate ion contains one phosphorus atom and four oxygen atoms.
A student named KClO3 potassium chlorine (V) oxide. Explain why the use of the stock system is not correct in this case, and write the correct name of the substance.
Roman numerals are used to show the charge or oxidation number of a metal that has more than one common oxidation number; chlorine is a nonmetal. The correct name is potassium chlorate.
When sulfur and oxygen combine to form a compound, which element should be written first? What values are considered in making this choice?
Sulfur is first because it has a lower electronegativity value
Vanadium has several oxidation states. Write correct formulas for vanadium (III) oxide and vanadium (V) oxide.
V2O3 & V2O5
The mass of 1 mol of NaNO3 is (1) 42 g (2) 53 g (3) 85 g (4) 116 g
(3) 85 g
The percent by mass of nitrogen in NH4NO3 is closest to (1) 15% (2) 20% (3) 35% (4) 60%
(3) 35%
Name each of the following binary ionic compounds. (a) NaBr (b) MgS (c) CaO (d) MgCl2 (e) AlF3 (f) CaI2
(a) sodium bromide (b) magnesium sulfide (c) calcium oxide (d) magnesium chloride (e) aluminum fluoride (f) calcium iodide
A compound has an empirical formula of CH2 and a molecular mass of 28 amu. What is its molecular formula?
C2H4
There is a 175-gram sample that contains 0.000250 gram of fluoride ions. How many parts per million of fluoride ions are present in the sample?
ppm = (0.000250)/(175.000250) x 1000000 = 1.4 ppm
An aqueous solution has 0.0070 gram of oxygen dissolved in 1000. grams of water. Calculate the dissolved oxygen concentration of this solution in parts per million.
ppm = (0.0070)/(100.0070) x 1000000 = 7 ppm
