Chem

Ammonium nitrate will decompose explosively at high temperatures to form nitrogen, oxygen, and water vapor. 2NH4NO3 (s) → 2N2 (g) + 4H2O(g) + O2 (g) What is the total number of liters of gas formed when 228 g NH4NO3 is decomposed? (Assume STP.)

224 L gas

Calculate and compare the mass of the reactants with the mass of the products for each equation in Problem 36. Show that each balanced equation obeys the law of conservation of mass.

A. 245.2 g B. 248.0 g C. 188.4 g

A car gets 9.2 kilometers to a liter of gasoline. Assuming that gasoline is 100% octane (C8H18), which has a density of 0.69 g/cm3, how many liters of air (21% oxygen by volume at STP) will be required to burn the gasoline for a 1250-km trip? Assume complete combustion.

1.1 x 10^6 L air

A 1004.0-g sample of CaCO3 that is 95.0% pure gives 225 L CO2 at STP when reacted with an excess of hydrochloric acid. CaCO3 + 2HCl → CaCl2 + CO2 + H2O What is the density (in g/L) of the CO2?

1.86 g/L

If the reaction below proceeds with a 96.8% yield, how many kilograms of CaSO4 are formed when 5.24 kg SO2 reacts with an excess of CaCO3 and O2? 2CaCO3 (s) + 2SO2 (g) + O2 (g) → 2CaSO4 (s) + 2CO2 (g)

10.7 kg CaSO4

Ethyl alcohol (C2H5OH) can be produced by the fermentation of glucose (C6H12O6). If it takes 5.0 h to produce 8.0 kg of alcohol, how many days will it take to consume 1.0 × 103 kg of glucose? (An enzyme is used as a catalyst.) C6H12O6 -> 2C2H5OH + 2CO2

13 days

Write a balanced chemical equation for each reaction. A. When heated, lead(II) nitrate decomposes to form lead(II) oxide, nitrogen dioxide, and molecular oxygen. B. The complete combustion of isopropyl alcohol (C3H7OH) produces carbon dioxide and water vapor. C. When a mixture of aluminum and iron(II) oxide is heated, metallic iron and aluminum oxide are produced.

2Pb(NO3)2 -> 2PbO + 4NO2 + O2 B. 2C3H7OH + 9O2 -> 6CO2 + 8H2O C. 2Al + 3FeO -> 3Fe + Al2O3

The manufacture of compound F requires five separate chemical reactions. The initial reactant, compound A, is converted to compound B, compound B is converted to compound C, and so forth. The diagram below summarizes the stepwise manufacture of compound F, including the percent yield for each step. Provide the missing quantities or missing percent yields. Assume that the reactant and product in each step react in a one-to-one mole ratio.

50.0% yield 0.500 mol 0.0500 mol 20.0% yield

SO3 can be produced in the following two-step process: FeS2 + O2 → Fe2O3 + SO2 SO2 + O2 → SO3 Assuming that all the FeS2 reacts, how many grams of SO3 are produced when 20.0 g of the FeS2 reacts with 16.0 g of O2?

6.51 g SO3

How many grams of beryllium are in 147 g of the mineral beryl (Be3Al2Si6O18)?

7.38 g Be

The white limestone cliffs of Dover, England, contain a large percentage of calcium carbonate (CaCO3). A sample of limestone with a mass of 84.4 g reacts with an excess of hydrochloric acid to form calcium chloride. CaCO3 + 2HCl → CaCO3 + CaCl2 + H2O + CO2 The mass of calcium chloride formed is 81.8 g. What is the percentage of calcium carbonate in the limestone?

87.4% CaCO3

Heating an ore of antimony (Sb2S3) in the presence of iron gives the element antimony and iron(II) sulfide. Sb2S3 (s) + 3Fe(s) → 2Sb(s) + 3FeS(s) When 15.0 g Sb2S3 reacts with an excess of Fe, 9.84 g Sb is produced. What is the percent yield of this reaction?

91.5%

How do you distinguish between a cation and an anion?

A cation has a positive charge, and an anion has a negative charge.

Explain the term mole ratio in your own words. When would you use this term?

A conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles

How many moles is each of the following? A. 47.8 g KNO3 B. 2.22 L SO2 (at STP) C. 2.25 × 10 22 molecules PCl3

A. 0.473 mol KNO3 B. 9.91 x 10^-2 mol SO2 C. 3.74 x 10^-2 mol PCl3

Carbon disulfide is an important industrial solvent. It is prepared by the reaction of coke with sulfur dioxide. 5C(s) + 2SO2 (g) → CS2 (l) + 4CO(g) A. How many moles of CS2 form when 2.7 mol C reacts? B. How many moles of carbon are needed to react with 5.44 mol SO2? C. How many moles of carbon monoxide form at the same time that 0.246 mol CS2 forms? D. How many mol SO2 are required to make 118 mol CS2?

A. 0.54 mol B. 13.6 mol C. 0.984 mol D. 236 mol

Balance each equation. A. Ba(NO3) 2 (aq) + Na2SO4 (aq) → BaSO4 (s) +NaNO3 (aq) B. AlCl3 (aq) + AgNO3 (aq) → AgCl( s) + Al(NO3) 3 (aq) C. H2SO4 (aq) + Mg(OH) 2 (aq) → MgSO4 (aq) + H2O( l)

A. 1, 1, 1, 2 B. 1, 3, 3, 1 C. 1, 1, 1, 2

Methanol (CH3OH) is used in the production of many chemicals. Methanol is made by reacting carbon monoxide and hydrogen at high temperature and pressure. CO(g) + 2H2 (g) → CH3OH(g) A. How many moles of each reactant are needed to produce 3.60 × 10 2 g CH3OH? B. Calculate the number of grams of each reactant needed to produce 4.00 mol CH3OH. C. How many grams of hydrogen are necessary to react with 2.85 mol CO?

A. 11.3 mol CO, 22.5 mol H2 B. 112 g CO, 16.0 g H2 C. 11.4 g H2

Calcium carbonate reacts with phosphoric acid to produce calcium phosphate, carbon dioxide, and water. 3CaCO3 (s) + 2H3PO4 (aq) → Ca3 (PO4) 2 (aq) + 3CO2 (g) + 3H2O(l) A. How many grams of phosphoric acid react with excess calcium carbonate to produce 3.74 g Ca3 (PO4) 2? B. Calculate the number of grams of CO2 formed when 0.773 g H2O is produced.

A. 2.36 g H3PO4 B. 1.89 g CO2

How many electrons, protons, and neutrons are in an atom of each isotope? (Chapter 4) A. titanium-47 B. tin-120 C. oxygen-18 D. magnesium-26

A. 22, 22, 25 B. 50, 50, 70 C. 8, 8, 10 D. 12, 12, 14

A bicycle-built-for-three has a frame, two wheels, six pedals, and three seats. The balanced equation for this bicycle is. F + 2W + 6P + 3S → FW2P6S3 How many of each part are needed to make 29 bicycles-built-for-three? A. frames B. wheels C. pedals D. seats

A. 29 frames B. 58 wheels C. 174 pedals D. 87 seats

The equation for one of the reactions in the process of reducing iron ore to the metal is: Fe2O3(s) + 3 CO(g) → 2 Fe(s) + 3 CO2 (g) A. What is the maximum mass of iron, in grams, that can be obtained from 454 g (1.00 lb) of iron(III) oxide? B. What mass of CO is required to reduce the iron(III) oxide to iron metal?

A. 347 g Fe B. 239 g CO

The reaction of fluorine with ammonia produces dinitrogen tetrafluoride and hydrogen fluoride. 5F2 (g) + 2NH3 (g) → N2F4 (g) + 6HF(g) A. If you have 66.6 g NH3, how many grams of F2 are required for complete reaction? B. How many grams of NH3 are required to produce 4.65 g HF? C. How many grams of N2F4 can be produced from 225 g F2?

A. 372 g F2 B. 1.32 g NH3 C. 123 g N2F4

Nitric acid and zinc react to form zinc nitrate, ammonium nitrate, and water. 4Zn(s) + 10HNO3 (aq) → 4Zn(NO3) 2 (aq) + NH4NO3 (aq) + 3H2O(l) A. How many atoms of zinc react with 1.49 g HNO3? B. Calculate the number of grams of zinc that must react with an excess of HNO3 to form 29.1 g NH4NO3.

A. 5.70 x 1021 atoms Zn B. 95.2 g Zn

Lithium nitride reacts with water to form ammonia and aqueous lithium hydroxide. Li3N(s) + 3H2O(l) → NH3 (g) + 3LiOH( aq) A. What mass of water is needed to react with 32.9 g Li3N? B. When the above reaction takes place, how many molecules of NH3 are produced? C. Calculate the number of grams of Li3N that must be added to an excess of water to produce 15.0 L NH3 (at STP).

A. 51.2 g H2O B. 5.71 x 1023 molecules NH3 C. 23.2 g Li3N

Hydrazine (N2H4) is used as rocket fuel. It reacts with oxygen to form nitrogen and water. N2H4 (l) + O2 (g) → N2 (g) + 2H2O(g) A. How many liters of N2 (at STP) form when 1.0 kg N2H4 reacts with 1.0 kg O2? B. How many grams of the excess reagent remain after the reaction?

A. 7.0 x 102 L N2 B. No reagant in excess

When 50.0 g of silicon dioxide is heated with an excess of carbon, 32.2 g of silicon carbide is produced. SiO2 (s) + 3C(s) → SiC(s) + 2CO(g) A. What is the percent yield of this reaction? B. How many grams of CO gas are made?

A. 96.4% B. 45.0 g

In a reaction chamber, 3.0 mol of aluminum is mixed with 5.3 mol Cl2 and reacts. The reaction is described by the following balanced chemical equation. 2Al + 3Cl2 → 2AlCl3 A. Identify the limiting reagent for the reaction. B. Calculate the number of moles of product formed. C. Calculate the number of moles of excess reagent remaining after the reaction.

A. Al B. 3.0 mol AlCl3 C. 0.8 mol Cl2

Write the formula for each compound. A. aluminum carbonate B. nitrogen dioxide C. potassium sulfide D. manganese(II) chromate

A. Al2(CO3)3 B. NO2 C. K2S D. MnCrO4

Write electron dot formulas for the following atoms. A. Cs B. Br C. Ca D. P

A. Cs B. Br C. Ca D. P See pg. 379

In an experiment, varying masses of sodium metal are reacted with a fixed initial mass of chlorine gas. The amounts of sodium used and the amounts of sodium chloride formed are shown on the following graph. A. Explain the general shape of the graph. B. Estimate the amount of chlorine gas used in this experiment at the point where the curve becomes horizontal

A. Initially, the amount of NaCl formed increases as the amount of Na used increases. For this part of the curve, sodium is the limiting reagent. Beyond a mass of about 2.5 g of Na, the amount of product formed remains constant because chlorine is now the limiting reagent. B. Chlorine becomes the limiting reagent when the mass of sodium exceeds 2.5 g. This corresponds to a mass of about 3.9 g chlorine.

Interpret each chemical equation in terms of interacting particles. A. 2KClO3 (s) → 2KCl(s) + 3O2 (g) B. 4NH3 (g) + 6NO(g) → 5N2 (g) + 6H2O(g) C. 4K(s) + O2 (g) → 2K2O(s)

A. Two formula units KClO3 decompose to form two formula units KCl and three molecules O2. B. Four molecules NH3 react with six molecules NO to form five molecules N2 and six molecules H2O. C. Four atoms K react with one molecules O2 to form two formula units K2O.

Interpret each equation in Problem 36 in terms of interacting numbers of moles of reactants and products.

A. Two mol KClO3 decompose to form two mol KCl and three mol O2. B. Four mol NH3 react with six mol NO to form five mol N2 and six mol H2O. C. Four mol K react with one mol O2 to form two mol K2O.

Identify the larger atom of each pair. A. sodium and chlorine B. arsenic and nitrogen C. fluorine and cesium

A. chlorine B. arsenic C. cesium

Name these ions. A. PO4 3− B. Al 3+ C. Se 2− D. NH4 +

A. phosphate ion B. aluminum ion C. selenide ion D. ammonium ion

Name each substance. A. SiO2 B. K2SO4 C. H2CO3 D. MgS

A. silicon dioxide B. potassium sulfate C. carbonic acid D. magnesium sulfide

Identify the spectator ions in each reaction in Problem 83.

A. sodium ion and nitrate ion B. aluminum ion and nitrate ion C. magnesium ion and sulfate ion

When comparing ultraviolet and visible electromagnetic radiation, which has (Chapter 5) A. a higher frequency B. a higher energy C. a shorter wavelength

A. ultraviolet B. ultraviolet C. ultraviolet

What is the molecular formula of oxalic acid, molar mass 90 g/mol? Its percent composition is 26.7% C, 2.2% H, and 71.1% O.

C2H2O4

Write a balanced chemical equation for the complete combustion of ribose, C5H10O5.

C5H10O5 + 5O2 -> 5CO2 + 5H2O

For the reaction below there is a 100.0 g of each reactant available. Which reagent is the limiting reagent? 2MnO2 + 4KOH + O2 + Cl2 → 2KMnO4 + 2KCl + 2H2O

KOH is the limiting reagent

Distinguish among single, double, and triple covalent bonds.

Single Bond: one pair shared electrons Double Bond: two pairs of shared electrons Triple Bond: three pairs of shared electrons

Given a certain quantity of reactant, you calculate that a particular reaction should produce 55 g of a product. When you perform the reaction, you find that you have produced 63 g of product. What is your percent yield? What could have caused a percent yield greater than 100%?

The percent yield is 115%; such a yield could be attributed to experimenter error, or to unreacted starting material, or to outside materials contaminating the product.

What is the significance of the limiting reagent in a reaction? What happens to the amount of any reagent that is present in an excess?

The reaction that is only partially consumed is reagent excess. The formed can be that product of amount maximum determines limiting.

How would you identify a limiting reagent in a chemical reaction?

To identify the limiting reagent, express quantities of reactants as moles; compare to the mole ratios from the balanced equation.

Would the law of conservation of mass hold in a net ionic equation? Explain.

Yes, a net ionic equation is balanced and thus obeys the law of conservation of mass.

Can a compound have both ionic and covalent bonds? Explain your answer.

Yes, an ionic compound with at least one polyatomic ion has covalent bonds.

What is the mass, in grams, of a molecule of benzene (C6H6)?

1.30 x 10^-22 g

Which of these elements form ions with a 2+ charge? A. potassium B. sulfur C. barium D. magnesium

C and D

What information about a chemical reaction is derived from the coefficients in a balanced equation?

The coefficients indicate the relative number of moles (or particles) of reactants and products.