ch 8 ALL
2S (s) + 3O2 (g) → 2SO3 (g) Give the correct setup for calculating the number of moles of SO3 that will form from the complete reaction of 1.5 mol of O2, according to the balanced reaction equation above?
(1.5×2) / 3 Reason: (1.5 mol O2) × (2mol SO3 / 3mol O2)
Select all the conversion factors that correctly represent the molar relationships in this balanced equation 2Al + 3Cl2 → 2AlCl3
(2mol Al / 3mol Cl2) (2mol AlCl3 / 2mol Al)
When heated, lithium reacts with nitrogen to form lithium nitride: 6Li(s) + N2(g) → 2Li3N(s) (a) What is the theoretical yield of Li3N in grams when 12.7 g of Li is heated with 34.7 gof N2? (b) If the actual yield of Li3N is 5.45 g, what is the percent yield of the reaction?
(a) 21.2 g (b) 25.7 %
Balance the following equations. Do not include the states of matter. (a) C + O2 → CO (b) KOH + H3PO4 → K3PO4 + H2O (c) N2 + H2 → NH3 (d) K + H2O → KOH + H2
(a) 2C + O2 → 2CO (b) 3KOH + H3PO4 → K3PO4 + 3H2O (c) N2 + 3H2 → 2NH3 (d) 2K + 2H2O → 2KOH + H2
Nitroglycerin (C3H5N3O9) is a powerful explosive. Its decomposition may be represented by 4C3H5N3O9 → 6N2 + 12CO2 + 10H2O + O2 This reaction generates a large amount of heat and gaseous products. It is the sudden formation of these gases, together with their rapid expansion, that produces the explosion. (a) What is the maximum amount of O2 in grams that can be obtained from 2.50 × 10^2 g of nitroglycerin? (b) Calculate the percent yield in this reaction if the amount of O2 generated is found to be 8.20 g
(a) 8.81 g (b) 93.1 %
Industrially, hydrogen gas can be prepared by combining propane gas (C3H8) with steam at about 400°C. The products are carbon monoxide gas (CO) and hydrogen gas (H2). (a) Write a balanced equation for the reaction. (b) How many kilograms of H2 can be obtained from 4.35 × 10^3 kg of propane? ____× 10^____ kg H2 gas
(a) C3H8(g) + 3H2O(g) → 3CO(g) + 7H2(g) (b) 1.39201026 × 10^3 kg H2 gas
Write an unbalanced equation to represent each of the following reactions: Do not include phase abbreviations. (a) Nitrogen and oxygen react to form nitrogen dioxide. (b) Dinitrogen pentoxide reacts to form dinitrogen tetroxide and oxygen. (c) Ozone reacts to form oxygen. (d) Chlorine and sodium iodide react to form iodine and sodium chloride. (e) Magnesium and oxygen react to form magnesium oxide.
(a) N₂ + O₂ → NO₂ (b) N₂O₅ → N₂O₄ + O₂ (c) O₃ → O₂ (d) Cl₂ + NaI → I₂ +NaCl (e) Mg + O₂ → MgO
Tetraphosphorous decoxide (P4O10) reacts with water to produce phosphoric acid. (a) Write the balanced equation for this reaction. Do not include states of matter in the equation. (b) Determine the number of moles of P4O10 required to produce 6.00 moles of phosphoric acid. (c) Determine the number of moles of water required to produce 6.00 moles of phosphoric acid.
(a) P₄O₁₀ + 6H₂O → 4H3PO4 (b) 1.50 mol (c) 9 mol
Determine whether each of the following equations represents a combination reaction, a decomposition reaction, or a combustion reaction: (a) 2NaHCO3 → Na2CO3 + CO2 + H2O (b) NH3 + HCl → NH4Cl (c) 2CH3OH + 3O2 → 2CO2 + 4H2O
(a) decomposition reaction (b) combination reaction (c) combustion reaction
Which of the following is the correct general formula for determining the atom economy of a given reaction or process?
(Σnℳ desired products / Σmℳ reactants) × 100%
Correctly place the steps in order for determining the molecular formula of a compound from combustion analysis data, if the approximate molar mass is known
1. Determine the empirical formula of the compound from the combustion analysis data 2. Use the empirical formula to calculate the empirical molar mass 3. Divide the approximate molar mass of the compound by the empirical molar mass, and round the quotient to the nearest integer 4. Multiply each subscripts in the empirical formula by the integer obtained
Correctly order the steps necessary to determine the empirical formula of a compound from combustion analysis data
1. Determine the masses of C and H from the masses of CO2 and H2O 2. Determine the mass of O, if present, by subtracting the masses of C and H from the total mass of the initial sample 3. Determine the number of each element in the compound, and use the results as subscripts in a chemical formula 4. Convert the subscripts in the formula to whole numbers, by dividing each by the smallest subscript
Correctly order the steps used in a combustion analysis experiment to determine the empirical formula of an organic compound.
1. The mass of the original sample is determined by weighing 2. The sample is heated in the presence of oxygen 3. The COO2 and H2O produced by the combustion are trapped separately 4. The mass of each product is determined. From the masses of CO2 and H2O collected, the percent composition and empirical formula are calculated
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.
1. Write a balanced equation for the reaction. 2. Convert the given mass into moles using molar mass. Convert moles of A to moles of B using a conversion factor derived from the balanced equation 3. Convert the moles of the second substance to mass using its molar mass
Correctly order the steps necessary to balance a chemical equation
1. Write an unbalanced equation 2. Balance the atoms of each element in turn, by adding coefficients before the chemical formulas of reactants and products-compounds first, elements last 3. Adjust the coefficients such that the smallest whole-number coefficients are used 4. Do a final check to make sure the equation is balanced
If the masses of two reactants are given for a balanced chemical reaction, place the steps necessary to calculate the mass of product formed in the correct order, first to last.
1. determine the moles of reactants present (divide the mass by its molar mass) 2. Determine the amount of product that could be formed from each reactant using the appropriate moles ratios 3. identify the limiting reactant as the reactant that produces the least amount of product 4. multiply the number of moles of product formed (from the limiting reactant) by the molar mass of the product to find the mass
B2 + 2AB → 2AB2 In the balanced reaction equation above, if 1.0 moles of B2 and 1.5 moles of AB are allowed to react to completion, what is the maximum amount of AB2 that can form?
1.5 moles Reason: The reaction requires 2 moles of AB for every 1 mole of B2, so AB is the limiting reagent. Each mole of AB produces 1 mole of AB2
What is the maximum mass, in grams, of P2I4 that can be prepared from 7.23 g of P4O6 and 11.20 g of iodine according to the reaction: 5P4O6 + 8I2 → 4P2I4 + 3P4O10
12.5 g P2I4
3H2 (g) + N2 (g) → 2NH3 (g) Calculate the mass of NH3 produced by the complete reaction of 2.55 g of H2 with excess N2 according to the equation above.
14.4 g [ Reason: 2.55 g H2 × (1mol H2 / 2.016g H2) × (2mol NH3 / 3mol H2) × (17.03g NH3 / 1mol NH3) = 14.4 g ]
What is the empirical formula of a compound containing C, H, and O if combustion of a 0.500-g sample of the compound produces 0.955 g CO2 and 0.587 g of H2O? (Put a number in every blank, even if it is a 0 or 1.) C____H____O____
2 6 1
When the following chemical equation is balanced correctly, what is the correct coefficient for each species? (Enter ALL numbers, including the digit 1, if required.) SO2(g) + O2 (g) → SO3 (g)
2 SO2 1 O2 2 SO3
Given the balanced equation below, determine the moles of HCl required and the mass of AgCl formed from the complete reaction of 18.3 g of Ag2S. Ag2S (s) + 2HCl (aq) → 2AgCl (s) + H2S (g)
21.2 g of AgCl 0.148 mol HCl
Butane burns in oxygen according to the following balanced reaction equation: 2C4H10 (g) + 13O2 (g) → 8CO2 (g) + 10H2O (g) When a 5.6-mole sample of butane reacts with O2, which of the following amounts of other reaction species are correct?
22 moles CO2 [Reason: (5.6 mol C4H10) × (8mol CO2 / 2mol C4H10) = 22 mol CO2 ] 36 moles O2 [Reason: (5.6 mol C4H10) × (13mol O2 / 2mol C4H10) = 36 mol O2 ]
The interhalogen compound ClF3 reacts with NH3 to produce three products according to the figure shown If 28.4 g of NH3 and 167.3 g of ClF3 are allowed to react, what masses of each product would be recovered assuming complete reaction? ____g N2 ____g Cl2 ____g HF
23.4 g N2 59.1 g Cl2 100 g HF
Ammonia is produced by the reaction of nitrogen and hydrogen according to the equation: N2(g) + 3H2(g) → 2NH3(g) Calculate the mass of ammonia produced when 20.0 g of nitrogen react with 14.8 g of hydrogen. ____ g NH3 Which is the excess reactant and how much of it will be left over when the reaction is complete: hydrogen or nitrogen ____g
24.31750519 g NH3 Hydrogen 10.48249661 g excess H2
Which of the following equations best represents the reaction shown in the diagram
2A + B → C + D
Write and balance the equation for the combination of ammonia gas with solid copper(II) oxide to produce copper metal, nitrogen gas, and liquid water. Include the states of matter.
2NH3(g) + 3CuO(s) → 3Cu(s) + N2(g) + 3H2O(l)
The fertilizer ammonium sulfate, (NH4)2SO4, is prepared by the reaction between ammonia (NH3) and sulfuric acid: 2NH3(g) + H2SO4(aq) → (NH4)2SO4(aq) How many kilograms of NH3 are needed to produce 1.30 × 10^5 kg of (NH4)2SO4? Enter your answer in scientific notation
3.35093901 × 10^4 kg
Consider the combustion of carbon monoxide (CO) in oxygen gas: 2CO(g) + O2(g) → 2CO2(g) Starting with 3.46 moles of CO, calculate the number of moles of CO2 produced if there is enough oxygen gas to react with all the CO.
3.46 mol CO2
Gaseous chlorine (Cl2) can be prepared by treatment of HCl with manganese(IV) oxide according to the reaction shown below. What is the atom economy for this process? 4HCl (aq) + MnO2 (s) → Cl2 (g) + MnCl2 (aq) + 2H2O (l)
30.5% Reason: Atom economy = (Σnℳdesired products / Σmℳreactants) × 100% = (70.90 / 4[36.46]+86.94) × 100% = 30.5%
When hydrogen gas is passed over powdered iron(III) oxide, iron metal and water vapor are formed. Select the correct balanced equation for this process
3H2 (g) + Fe2O3 (s) → 2Fe (s) + 3H2O (g)
interpretations of the balanced equation 4C (s) + S8 (s) → 4CS2 (l)
4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2. Carbon and S8 are reactants and CS2 is the product. 4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2
Fermentation is a complex chemical process of wine making in which glucose is converted into ethanol and carbon dioxide: C6H12O6 → 2C2H5OH + 2CO2 glucose ethanol Starting with 827.6 g of glucose, what is the maximum amount of ethanol in grams and in liters that can be obtained by this process (density of ethanol = 0.789 g/mL)?
423.2572803 g 0.536447757 L
2Al2O3 (s) → 3O2 (g) + 4Al (s) Given the balanced equation above, match the quantities of reactants and products.
5.0 moles Al2O3 = 7.5 moles O2 2.0 moles Al = 1.5 moles O2 6.0 moles Al = 4.5 moles O2
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
Hydrogen fluoride is used in the manufacture of Freons (which destroy ozone in the stratosphere) and in the production of aluminum metal. It is prepared by the reaction: CaF2 + H2SO4 → CaSO4 + 2HF In one process, 6.15 kg of CaF2 is treated with an excess of H2SO4 and yields 2.45 kg of HF. Calculate the percent yield of HF.
77.7 % yield
A particular reaction is expected to yield 125 g of Ca. The actual amount of Ca obtained is equal to 105 g. Calculate the % yield for the reaction.
84.0% Reason: (105 g / 125 g) × 100 = 84.0%
Balance the unbalanced equation below, using lowest possible whole-number coefficients, then match each substance to the correct coefficient as indicated. Al2S3 (s) + H2O (l) → Al(OH)3 (aq) + H2S (g)
Al2S3 = 1 H2O = 6 Al(OH)3 = 2 H2S = 3
A + 2B → C Reactants A (blue) and B (red) react according to the balanced equation above. Which of the following statements are correct?
B is the limiting reactant. A is the reactant in excess.
Menthol is a flavoring agent extracted from peppermint oil. It contains C, H, and O. In one combustion analysis, 10.00 mg of the substance yields 11.53 mg H2O and 28.16 mg CO2. What is the empirical formula of menthol? Add subscripts to complete the empirical formula. CHO
C10H20O
Hydrocarbons are compounds that contain only carbon and hydrogen. Combustion of a sample of a particular hydrocarbon gave 5.86 g of CO2 and 1.37 g of H2O. What is the empirical formula of the hydrocarbon?
C7H8 Reason: 5.86 g CO2 × (12.01g C / 44.01g CO2) × (1mol C / 12.01g C) = 0.133 mol C. 1.37 g H2O × (2.016g H / 18.02g H2O) × (1mol H / 1.008g H) = 0.152 mol H. 0.152/0.133 = 1.14 = 8/7. Hence, C_0.133H_0.152 = C7H8
Match each reaction type with its distinguishing feature
Combination = Two or more reactants combine to form a single product. Decomposition = A single reactant forms two or more products. Combustion = A reactant rapidly reacts with O2(g) to form oxides, such as CO2(g).
What type of reaction is described by the equation shown below? CS2 (l) + 3O2 (g) → CO2 (g) + 2SO2 (g)
Combustion (Reason: In this reaction CS2 is being burned in oxygen. The reaction is therefore a combustion reaction.)
Match each of the following reactions with its general type
Decomposition = CuCO3 (s) → CuO (s) + CO2 (g) Combination = PF3 (g) + F2 (g) → PF5 (g) Combustion = C2H4 (g) + 3O2 (g) → 2CO2 (g) + 2H2O (l)
Which statement does NOT correctly describe a step in determining the empirical formula of a compound from combustion analysis data?
Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion. (Reason: The mass of a third element is found by subtracting the masses of carbon and hydrogen from the total mass of the original sample.)
A student has done experiments to determine the empirical formula and the approximate molar mass of a substance. Which of the following methods should be used to determine the molecular formula?
Divide the approximate molar mass by the empirical formula mass
Which of the substances below are represented with their proper formulas? Elemental phosphorus, P4 Elemental oxygen, O2 Elemental copper, Cu Elemental sodium, Na+ Elemental boron, B2
Elemental phosphorus, P4 Elemental oxygen, O2 Elemental copper, Cu
What information can be obtained from a combustion analysis
Empirical formula of an organic compound (Reason: Combustion analysis gives the percent composition of each element, which allows us to determine the empirical formula) Percent composition of an organic compound
True or false: In order to balance the reaction of hydrogen gas (H2) with oxygen gas (O2) to form liquid H2O, a student adds a subscript of 2 to H2O (forming H2O2). This is an acceptable method of balancing the reaction described
False (Reason: Formulas of species involved in chemical reactions should never be changed, because this changes the identity of the compound. Only coefficients should be added to balance chemical equations.)
Which equation is a correct representation of the reaction shown? In the illustration, carbon is black, oxygen is red, and hydrogen is white
H2CO3 → CO2 + H2O
Write and balance the chemical equation that represents the reaction of aqueous sulfuric acid with aqueous sodium hydroxide to form water and sodium sulfate. Include phases.
H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l)
actions are permitted in balancing a chemical equation
Inserting coefficients before the formulas of reactants and products Multiplying all coefficients by a common factor
Of the elements listed, select all that typically occur as diatomic molecules. Sulfur, Carbon, Iodine, Helium, Nitrogen
Iodine (Reason: Iodine occurs as the diatomic molecule I 2 Nitrogen (Reason: Nitrogen occurs as the diatomic molecule N2)
Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark brown gas: 2NO(g) + O2(g) → 2NO2(g) In one experiment, 0.893 mol of NO is mixed with 0.519 mol of O2. Determine which of the two reactants is the limiting reactant. Calculate also the number of moles of NO2 produced.
Limiting reactant: NO Moles of NO2 produced: 0.893 mol
"Aqueous solutions of calcium hydroxide and sodium phosphate react to form aqueous sodium hydroxide and solid calcium phosphate." In the reaction represented by the statement above, what are the reactants?
Na3PO4 Ca(OH)2
In a balanced chemical equation, which of the following must be the same on both sides of the equation
Number of atoms of each element
Consider the reaction 2A + B → C In the diagram here that represents the reaction, which reactant, A or B, is the limiting reactant?
The limiting reactant = A
describe the limiting reactant in a reaction?
The maximum amount of product formed is the amount that can be formed from the limiting reactant. The limiting reactant limits the amount of product that can form.
Select all the statements that correctly describe steps in the procedure used to identify a limiting 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. Calculate the amount of product that could be formed from each reactant.
describe the information that can be gained from a balanced chemical equation?
The relative quantities (moles) of the substances involved. The identities of substances involved. The physical states of reactants and products, usually.
describe the symbols used to write a balanced equation
The symbol (g) indicates a substance in the gas phase. The symbol (s) is used for a powdered substance [Reason: A powder is a solid, and the symbol (s) would be used]
In an experiment, a student calculates the maximum expected yield of her product to be 3.2 grams. However, when she weighs the purified product, she finds that she only has 2.8 grams, or only 88% of the maximum expected. Match each type of yield to its numerical value.
Theoretical yield = 3.2 Actual yield = 2.8 Percent yield = 88
Match each type of reaction yield with the correct definition.
Theoretical yield = The maximum possible amount of product, calculated from the molar ratio in the balanced chemical equation Actual yield = Amount of product obtained experimentally from a chemical reaction Percent yield = (amount of product obtained / amount of product possible) × 100
interpret the balanced chemical equation 4HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2H2O (l) + Cl2 (g)?
Water is both a solvent and a product in this reaction. HCl is a reactant in this equation. The MnCl2 produced is dissolved in water.
Which of the following steps would be required to convert between the masses of two substances that are related through a chemical reaction? (For example, calculating the mass of product formed from the mass of a reactant.)
Write a conversion factor using the coefficients from the balanced equation, and convert to moles of the second substance. Convert from the given mass to moles of the same substance. Write a balanced chemical equation for the reaction.
The theoretical determination of how much of the starting mass of reactants ends up in the final mass of desired products is known as economy.
atom
In a(n) ____ reaction, a single product is formed from two or more reactants. The opposite of this reaction type is a(n) ____ reaction, in which a single reactant produces two or more products
combination decomposition
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 (or symbols, formula, symbol, formulae, notation) quantity (or quantities, amounts, amount, proportions, ratios, moles, molar ratios, molar ratio, ratio)
The ____ reactant in a reaction is one that limits the amount of product formed. This reactant will be completely used up in the reaction. Any reactants that are not used up are said to be ____ reactants
limiting excess
Ammonia is a colorless gas with a pungent, characteristic odor. It is prepared by the reaction between hydrogen and nitrogen: 3H2(g) + N2(g) → 2NH3(g) In a particular reaction, 9.3 moles of NH3 were produced. How many moles of H2 and how many moles of N2 were consumed to produce this amount of NH3?
moles H2 = 13.95 moles N2 = 4.65
Nitrogen and hydrogen react to form ammonia according to the following balanced equation: N2(g) + 3H2(g) → 2NH3(g) Calculate the number of moles of hydrogen required to react with 0.0747 mole of nitrogen, and the number of moles of ammonia that will form. moles of hydrogen = ____mol moles of ammonia = ____mol
moles of hydrogen = 0.2241 mol moles of ammonia = 0.1494 mol
N2O4 → 2NO2 In the reaction represented by the chemical equation above, NO2 is the formula of the ______ and N2O4 is the formula of the ______
product, reactant
The concept of atom economy consists of determining ______.
the mass of reactants that can end up in the desired product, according to the balanced chemical equation
Match each symbol used in writing a chemical equation with its correct meaning.
→ indicates the conversion of reactants to products (s) indicates a substance in the solid state (aq) indicates a substance dissolved in H2O Δ indicates that the reaction is heated (l) indicates a substance in the liquid state
