General Chemistry
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Alkaline batteries are used in most household items. The overall cell reaction is:
Zn(s) + 2 MnO2(s) ⇌ ZnO(s) + Mn2O3(s)
Calculate the mass of ZnO produced from 6.25×10–2 g of MnO2.
Bleaching of hair usually involves the reaction of hydrogen peroxide (H2O2) with the melanin (C18H10N2O4) in hair. As the bleaching solution is rubbed to hair, melanin is oxidized by hydrogen peroxide: C18H10N2O4 + 34 H2O2 → 2 NH3 + 36 H2O + 18 CO2. A bleaching solution contains 9% H2O2 by mass. If 20 g of the bleaching solution is used, calculate the mass (in mg) of melanin that is oxidized.
In a laboratory, a student accidentally spills 300 g of glacial acetic acid (CH3CO2H) which is 99.5% acetic acid by mass. Calculate the mass (in g) of sodium bicarbonate required to neutralize the spill.
A vat containing 5 kg of acetic acid was accidentally spilled over a number of marble blocks. Acetic acid reacts with the calcite (CaCO3) in marble: CaCO3(s) + CH3CO2H(aq) → (CH3CO2)2Ca(aq) + CO2(g) + H2O(l). If the marble blocks have a mass of 100 g, determine the number of blocks that was damaged. Assume the blocks are made of pure calcite and it is considered damaged if 5.0% of its mass reacted.
Decane (C10H22) is a component of diesel. Assuming diesel is 100% decane, the complete combustion of decane produces CO2 and H2O, and the density of decane is 0.73 g/mL, calculate the mass of CO2 (in kg) produced if the yearly diesel consumption of the U.S. is 1.78 × 1011 L.
Fireclay is a ceramic usually made by mixing Al(OH)3, SiO2, and Mg(OH)2. The resulting mixture is then heated to 1100 ºC to form Al2O3 and MgO by removal of water. The fireclay product has a mass percent composition of 45% Al2O3, 50% SiO2, and 5% MgO. Calculate the amount of each starting material required to create 200 g of fireclay.
Fermentation involves converting glucose (C6H12O6) into ethanol (C2H5OH) and carbon dioxide. Calculate the mass (in g) and volume (in L) of ethanol produced by the fermentation of 105.3 g of glucose. Assume that at 25 ºC, 1 mole of ethanol has a volume of 58.39 mL.
Ba(OH)2 or KOH reacts with acids in neutralization reactions. The unbalanced equations are
Ba(OH)2(aq) + HCl(aq) → BaCl2(s) + H2O(l)
KOH(aq) + HCl(aq) → KCl(s) + H2O(l)
How many kilograms of each item are required to neutralize 1.50 gallons of HCl (1.18 g/mL)?
Pure aluminum can be extracted from the reaction of alumina, Al2O3, with carbon: Al2O3 + C → Al + CO2. Balance the chemical equation and calculate the mass of C needed to react with 500 g alumina.
7.00 g of pure Fe metal is produced by the reduction of a 5.18 g sample containing Fe2O3 and FeO. How many grams of Fe2O3 and FeO are in the original sample?
The structure of leucine, an amino acid, is shown below. A 0.02 mol sample of leucine undergoes combustion analysis. Calculate the moles of CO2 and H2O formed.
MX3 is formed from the reaction between an unidentified metal M and an unidentified halogen X. The compound decomposes when heated and produces MX and X2.
MX3(s) → MX (s) + X2(g)
When 1.18 g of MX3 is heated, 1.07 g of M and 34.76 mL of X2 gas are obtained. The volume of 1.00 mol of X2 under the reaction condition is 22.41 L. Determine the identity of halogen X and its atomic weight.
A sample of vinegar containing acetic acid and water is burned. Vinegar burns and produces water, while the water in the sample just evaporates. The water produced by the combustion of vinegar, as well as the water that evaporates, is collected. The combustion reaction is
CH3COOH (aq) + O2 (g) → CO2 (g) + H2O (g)
When 5.00 g of the sample is burned, 3.64 g of water is collected. How many grams of acetic acid and water are there in the original sample?
The following equation shows what happens when a compound with the formula XCl2 meets aqueous AgC2H3O2:
XCl2 (aq) + 2 AgC2H3O2 (aq) → X(C2H3O2)2 (aq) + 2 AgCl (s)
When 1.20 g of XCl2 in a solution was mixed with too much aqueous AgC2H3O2 in water, 2.53 g of solid AgCl was made. What is the name of the atom X?
CO2 gas is produced by heating H2CO3 at 127 °C. The volume of 1.00 mol of CO2 is 32.85 L under the same conditions. How much gas in liters is produced when 24.7 g of H2CO3 is heated?
The diagram below represents the reaction between ammonia and oxygen to produce nitric oxide and water. Use this diagram to calculate the number of moles of nitric oxide that could be produced from 12 moles of ammonia.
Nitrogen gas (N2) reacts with magnesium to form magnesium nitride (Mg3N2) at 800 °C. The source of nitrogen in this reaction is the atmospheric nitrogen from the air. Air contains about 78% nitrogen, 21% oxygen, and 1% other gases. Since the reaction is exothermic, the released heat can result in the reaction between nitrogen and oxygen to form nitric oxide (NO). If 95% of the nitrogen in the air reacts with magnesium to form magnesium nitride and the remainder reacts with oxygen to form nitric oxide, how many grams of nitric oxide would be produced when 45.0 g of magnesium reacts with excess air?
In the reaction between sodium bicarbonate (NaHCO3) and acetic acid (CH3COOH), carbon dioxide gas is evolved:
NaHCO3(s) + CH3COOH(aq) → CH3COONa(aq) + CO2(g) + H2O(l)
Calculate the mass of NaHCO3(s) required to produce 697 in3 of carbon dioxide gas to fill an average-sized balloon. The density of carbon dioxide is 1.78 g/L.
The laboratory preparation of oxygen gas is done by thermal decomposition of potassium chlorate (KClO3):2 KClO3(s) → 2 KCl(s) + 3 O2(g)What mass of KClO3 is required to produce 45.00 L of oxygen gas at room temperature? The density of oxygen gas is 1.110 g/L.
A metal from group 2A forms a bromide with the formula MBr2 and chloride with the formula MCl2. The bromide can be converted into chloride when reacted with chlorine gas.MBr2 + Cl2 → MCl2 + Br2When a 0.2554 g sample of MBr2 is reacted with excess Cl2, 0.1321 g of MCl2 is produced. What is the atomic weight of the metal M?
Decomposition of nitromethane (CH3NO2) takes place according to the following reaction:2 CH3NO2(l) → 2 CO(g) + H2(g) + N2(g) + 2 H2O(g)How many moles of gases are produced when a 3.125 mL sample of nitromethane is completely decomposed? The density of nitromethane is 1.1371 g/mL.
A reaction that takes place during the extraction of copper metal is the formation of copper metal and CO from Cu2O and solid carbon. Calculate the mass of Cu2O required to form 596 kg of copper and the amount of CO produced in the same scenario.
Lighters commonly use butane gas (C4H10) for fuel. Calculate the mass of carbon dioxide (in g) produced upon the complete combustion of 56.0 mL of butane fluid (approximate contents of a refill bottle). Assume that the density of the fluid is 0.573 g/mL.
The reaction of Fe2O3 and CO produces Fe3O4 and CO2. The Fe3O4 can be converted to FeO with its reaction with CO, forming CO2 as a byproduct. FeO can then react with CO to form Fe and CO2. If there are 63.5 g of Fe2O3 initially, calculate the amount of Fe produced following the series of reactions.
The compound zirconium silicate, ZrSiO4(s), can be prepared by reacting ZrO2(s) and SiO2(s) at high temperatures. Calculate the moles and mass of ZrO2 needed to produce 3.500 g of ZrSiO4(s). Assume that the reaction goes to completion.
Lauryl sulfate is an anion found in cleaners and detergents. Its structure is shown below:
Assuming lauryl sulfate decomposes according to the following reaction:
C12H25SO4–(aq) + 18 O2(aq) → 12 CO2(aq) + 12 H2O(l) + H+(aq) + SO42–(aq)
Calculate the mass of O2 required to decompose 15.0 g of lauryl sulfate.
An alkaline battery has the following overall reaction:
2 MnO2(s) + Zn(s) + 2 H2O(l) → 2 MnO(OH)(s) + Zn(OH)2(s)
In a certain period of discharge, 131 g of Zn from the anode was converted into Zn(OH)2(s). Calculate the amount (g) of MnO2(s) that is reduced at the cathode at the same time.
Calculate the mass of CO2 (in kg) formed when 2.65 kg of n-hexane is combusted.
H2 reacts with Cl2 to produce HCl. Determine the mass of H2 required to react with 18.9 g of Cl2 and the mass of HCl produced from it.
A 5.37 g of an alloy containing nickel and copper is placed in HCl liquid. If 6.72 g of CuCl is acquired, determine the mass of nickel and copper in the alloy. Assume all HCl reacts with copper.
For the following unbalanced reaction,
SrS + Co2(SO4)3 → SrSO4 + Co2S3
Determine the mass of Co2(SO4)3 required to completely react with 78.6 g of SrS.
The reaction between zinc and iodine produces zinc iodide. For a mixture of zinc and iodine, 1.2 mol Zn, 3.4 mol I2 and 2.4 mol ZnI2 were measured before the reactants were used up. Calculate the initial amount of the reactants.
Magnesium displaces aluminum in aluminum oxide to produce magnesium oxide.
3 Mg2+ + Al2O3 → 3 MgO + 2 Al3+
If magnesium is added to a solution of 0.50 L aluminum oxide in the form of magnesium nitrate, calculate the mass of magnesium nitrate needed to displace 0.45 M Al3+ ions
Determine the mass of HBr that can react with 2.67 g of Sr(OH)2.
Sr(OH)2 + 2 HBr → SrBr2 + 2 H2O
Determine the mass of Br2 produced from the reaction of 7.00 mol of HBr with excess K2SO4.
K2SO4 + 2 HBr → K2SO3 + Br2 + H2O
A 150.0 g mixture of MgCO3, Mg(ClO3)2, and Mg(HCO3)2 produces 65.11 g of CO2, 18.68 g of O2, and 9.64 g of H2O.
MgCO3 (s) → MgO (s) + CO2 (g)
Mg(ClO3)2 (s) → MgCl2 (s) + 3 O2 (g)
Mg(HCO3)2 (s) → MgO (s) + 2 CO2 (g) + H2O (g)
Determine the composition of the mixture.
Methane, ethane, and propane are burnt in excess oxygen in three separate reaction vessels. The mass burnt for each fuel was 3.45 g. Determine which fuel will generate the largest amount of CO2?
If 5.7 moles of N2O5 react, how many moles of NO2 form?
N2O5( g) → NO2( g) + O2(g)
You want to dissolve an aluminum rod weighing 1.5 kg. What is the minimum mass of H2SO4 (in g) required to react with aluminum? How much (in g) H2 gas is produced if the aluminum rod reacts completely?
Al(s) + H2SO4(aq) → Al2(SO4)3(aq) + H2(g)
A petroleum sample is composed of 23.29% heptane (C7H16), 52.18% hexane (C6H14), and the rest octane (C8H18). If 38 kg of this sample is combusted completely, calculate the maximum mass of carbon dioxide formed.
According to the following chemical equation, how many grams of HBr are needed to completely dissolve 1.3 kg pure iron?
Fe(s) + HBr(aq) → FeBr2(aq) + H2(g).
Calculate grams of product that form when 23.59 g of O2 completely reacts. Assume other reactant is in excess.
2 Sr(s) + O2(g) → 2 SrO(s)
Determine the mass (in grams) of Ca(OH)2 required to completely neutralize 3.41 g of HC2H3O2.
HC2H3O2(aq) + Ca(OH)2(aq) → H2O(l) + Ca(C2H3O2)2(aq)
Note: make sure to balance the equation.
Calculate the mass of oxygen consumed in the combustion of 2.21 g of C3H8
Write the balanced reaction for the reaction of aluminum sulfide with water producing aluminum hydroxide and hydrogen sulfide.
If 10.5 g of aluminum sulfide was allowed to react calculate the mass of aluminum hydroxide produced.
Potassium superoxide, KO2, is used to convert carbon dioxide and water into oxygen
4 KO2 (s) + 4 CO2 (g) + 2 H2O (g) → 4 KHCO3 (s) + 3 O2 (g)
Calculate the number of molecules of O2 (g) produced from the 0.0692 g CO2 (g)
Barium chloride and water are produced by the reaction of hydrochloric acid and barium hydroxide:
2HCl (aq) + Ba(OH)2 (aq) → BaCl2 (aq) +2H2O (l)
Consider 6 moles of barium hydroxide that reacted.
Calculate the amount of the products made and the amount of the other reactant consumed
____ moles of hydrochloric acid is consumed.
____ moles of barium chloride and ____ moles of water are produced.
The balanced reactions below shows the combustion of propane:
C3H8 (g) + 5 O2 (g) → 3 CO2 (g) + 4 H2O (g)
If 132.1 g of C3H8(g) is completely combusted, calculate the mass in grams of oxygen needed for this process.
The combustion of octane is represented by the balanced reaction below:
2 C8H18 + 2 5O2 → 16 CO2 + 18 H2O
If 39.27 g of C8H18 is combusted, calculate the moles of CO2 produced
Assume that you are performing a stoichiometric calculation wherein you want to calculate the mass of the product from a given mass of reactant. After writing the balanced chemical equation and determining the mole ratio, what is the next step in the mass calculation for the reaction?
True or False: The balanced chemical equation Na3PO4(aq) + CaCl2(aq) → Ca3(PO4)2(s) + NaCl(aq) can be used to determine the stoichiometry of the reaction, and the mole ratio of Na3PO4 to NaCl is 1:1.
Which of the following must be done in order to use the mole ratio in stoichiometry problems?
Which of the following is required in each of all types of reaction stoichiometry calculations?
What is the typical initial procedure for determining the stoichiometry of a reaction?
What is the fundamental principle that stoichiometry is based on?
Give the general procedure for determining the required quantity of reactant A to produce a certain mass of product B in a hypothetical chemical reaction.
Solid potassium chlorate (KClO3) decomposes into solid potassium chloride (KCl) and oxygen gas (O2). Assuming that you start with 5.00 g of KClO3, how do you calculate the grams of KCl produced? Show the step-by-step calculation.
Which of these statements provides the best explanation for the importance of mole ratios in stoichiometric calculations?
Choose the statement that best defines stoichiometry.
Which of the following refers to the relationship between the amounts of substances involved in a balanced chemical reaction?
Which of the following can be used to determine the amount of the reactants and products in a reaction?
Olive oil (C88H164O10) is an oil extracted from the olive plant. What is the mass of H2O produced in the metabolism of 1.00 kg of olive oil? Assume that C88H164O10 only reacts with O2 to produce CO2 and H2O.
A hypothetical method uses the following equation to determine the amount of SO2 in the gas by passing a sample through a sodium carbonate-containing vessel which removes the SO2.
Na2CO3(aq) + H2O(l) + 2 SO2(g) → 2 NaHSO3(aq) + CO2(g)
How much Na2CO3 in moles is required for the removal of 6.29×10−6 mol of SO2?
Propane (C3H8) is a component of liquefied petroleum gas (LPG). It burns completely as follows: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)How many grams of O2 are needed to be able to burn 13.5 gal of C3H8 if the density of propane at 25.0 °C is 0.493 g/mL?
Soda lime (Ca(OH)2) and nitrogen dioxide (NO2) can react according to the following reaction:4 NO2(g) + 2 Ca(OH)2(s) → Ca(NO3)2(aq) + 2 H2O(l) + Ca(NO2)2(aq)This demonstrates how Ca(OH)2 can be used to absorb NO2 gas. How many moles of NO2 can be absorbed when 0.367 mol Ca(OH)2 reacts in this manner?
Soda lime (Ca(OH)2) and nitrogen dioxide (NO2) can react according to the following reaction:
4 NO2(g) + 2 Ca(OH)2(s) → Ca(NO3)2(aq) + 2 H2O(l) + Ca(NO2)2(aq)
This demonstrates how Ca(OH)2 can be used to absorb NO2 gas. How many grams of Ca(OH)2 are required to absorb 5.29 g of NO2?
Propane (C3H8) is a component of liquefied petroleum gas (LPG). It burns completely as follows: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)
How many moles of O2 must be burned to produce 6.67 moles of C3H8?
Calculate the moles of PCl3 formed when 87.2 g of P4 reacts with excess Cl2. Reaction: P4(s) + 6 Cl2(g) → 4 PCl3(l)
The process of CAD welding involves copper (II) oxide and aluminum reacting: 3 CuO(s) + 2 Al(s) → 3 Cu(s) + Al2O3. Calculate the mass of Al needed to react with 6.4 g of CuO and the mass of Cu formed, assuming the reaction goes to completion.
For the reaction 2 A + B → 3 C + 2 D, fill the table below with the missing values. If a value for a reactant is given, provide the correct values for both products and the other reactant. If a value for a product is given, provide the correct values for both reactants and the other product.
For this reaction, calculate the mass (in grams) of the product that forms when 15.39 g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant.
An important reaction that takes place in a blast furnace during the production of iron is the formation of iron metal and CO2 from Fe2O3 and CO. Determine the mass of Fe2O3 required to form 910 kg of iron. Determine the amount of CO2 that forms in this process.
The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g) (c) Octane has a density of 0.692 g/mL at 20°C. How many grams of O2 are required to burn 22.0 gal of C8H18?
The combustion of gasoline produces carbon dioxide and water. Assume gasoline to be pure pentane (C5H12) and calculate the mass (in kg) of carbon dioxide that is added to the atmosphere per 1.0 kg of pentane burned. (Hint: Begin by writing a balanced equation for the combustion reaction.)
A liquid fuel mixture contains 31.25% pentane (C5H12), 17.43% hexane (C6H14), and the rest nonane (C9H20). What is the maximum mass of carbon dioxide produced by the complete combustion of 10.0 kg of this fuel mixture?
Hydrofluoric acid, HF(aq), cannot be stored in glass bottles because compounds called silicates in the glass are attacked by the HF(aq). Sodium silicate Na2SiO3, for example, reacts as follows: Na2SiO3(s) + 8 HF(aq) → H2SiF6(aq) + 2 NaF(aq) + 3 H2O(l)
How many grams of NaF form when 0.630 mol of HF reacts with excess Na2SiO3?
Magnesium sulfide reacts with water to form magnesium hydroxide and hydrogen sulfide.
(a) Write the balanced chemical equation for this reaction.
(b) How many grams of magnesium hydroxide are obtained from 11.5 g of magnesium sulfide?