Worksheet: Atom Economy

In this worksheet, we will practice calculating the atom economy for reactions using the formula masses of the reactants and desired products.

Q1:

Which of the following is the best definition for the atom economy of a reaction?

  • AThe mass of useful products as a percentage of the mass of reactants
  • BThe number of atoms in the useful products as a percentage of the number of atoms in the reactants
  • CThe percentage of atoms in the reactants that are converted to waste
  • DThe ratio of the number of atoms in the products to the number of atoms in the reactants
  • EThe percentage of atoms in the reactants derived from economical sources

Q2:

Which of the following reactions has the greatest atom economy for the production of hydrogen?

  • ACHO+7HO12H+6CO6105222
  • BCH+HOCO+3H422
  • CCO+HOCO+H222
  • DZn+2HClZnCl+H22
  • E2Al+2NaOH+6HO2Na[Al(OH)]+3H242

Q3:

What is the formula for calculating the atom economy of a reaction?

  • AAtomeconomysumofrelativeformulamassesofthereactantssumofrelativeformulamassesoftheproducts=
  • BAtomeconomynumberofatomsintheusefulproductnumberofatomsinthereactants=×100%
  • CAtomeconomyrelativeformulamassoftheusefulproductsumofrelativeformulamassesofthereactants=×100%
  • DAtomeconomynumberofatomsinthereactantsnumberofatomsintheusefulproduct=
  • EAtomeconomysumoftherelativeformulamassesoftheproductssumofrelativeformulamassesofthereactants=×100%

Q4:

Shown in the table are the molar masses of calcium oxide, calcium carbonate and carbon dioxide.

SubstanceCaOCaCO3CO2
Molar Mass (g/mol)5610044

Calcium oxide can be made from calcium carbonate by heating, according to the equation: CaCOCaO+CO32.

To the nearest percentage unit, what is the atom economy for the production of calcium oxide via this process?

Q5:

Barium sulfate (BaSO)4 can be made by adding sodium sulfate (NaSO)24 to a solution of barium chloride (BaCl)2, as illustrated by the equation: BaCl()+NaSO()BaSO()+2NaCl()2244aqssaq.

To the nearest percentage unit, what is the atom economy for the production of barium sulfate via this process?

Q6:

Calcium metal can be used to produce pure rubidium from its chloride according to the equation: Ca()+2RbCl()CaCl()+2Rb()sssl2.

What is the atom economy for the production of rubidium by this process, to the nearest percentage unit?

Q7:

Raising agents are used in baking to help things rise. This is done by the production of CO2, such as in the reaction shown. 2NaHCO+Ca(HPO)NaHPO+CaHPO+2CO+2HO324224422

Which product in this chemical reaction gives the highest atom economy?

  • ACO2
  • BNaHPO24
  • CHO2
  • DCaHPO4

Q8:

Which of the following statements about atom economy is not true?

  • AReactions with a low atom economy produce more waste products.
  • BReactions with a low atom economy are not sustainable.
  • CReactions with a low atom economy are not usually profitable.
  • DReactions with a low atom economy are usually greener.
  • EReactions with a low atom economy use up resources more quickly.

Q9:

Which of the chemical reactions below does not have an atom economy of 100%?

  • A2H+O2HO222
  • BS+OSO22
  • CNi+4CONi(CO)4
  • DCO+HOCO+H222
  • EN+3H2NH223

Q10:

The atom economy of a chemical reaction is not the only factor that industries need to consider. Which of the following is not an important factor of a chemical reaction that a company needs to consider?

  • APercentage yield
  • BReversible reactions
  • CReaction conditions
  • DRate of reaction
  • EAppearance

Q11:

A chemical reaction for the formation of compound E has an atom economy of 52.3%. The relative formula masses of A and B are 117 and 36 respectively. What is the relative formula mass of E? Give your answer to the nearest whole number. A+BC+D+E

Q12:

Phenol (CHOH)65 is a very important commercial molecule that can be produced in numerous ways. Put the chemical reactions below in order of increasing atom economy. CHSOH+2NaOHCHOH+NaSO+HO(1)CHCl+NaOHCHOH+NaCl(2)CH+NOCHOH+N(3)CHCH+2OCHOH+CO+HO(4)65365232656566265265326522

  • A4, 1, 3, 2
  • B3, 4, 2, 1
  • C2, 3, 1, 4
  • D1, 4, 2, 3
  • E1, 2, 4, 3

Q13:

Elemental silicon can be produced through two different methods. The chemical reaction for each method is shown below. SiO+2CSi+2CO(1)3SiO+4Al3Si+2AlO(2)2223

By calculating the atom economy for each reaction, determine which reaction is more economical.

Q14:

Sodium azide (NaN)3 is an important compound found in car airbags. One method of producing NaN3 is shown in the following equation. 2NaNH+NONaN+NaOH+NH2233

By calculating the atom economy, determine the percentage of the wasted starting materials.

Q15:

The formation of a commercially important compound is shown in the following chemical equation. 4NO+2HO2HNO+otherproducts22X

If the atom economy of the reaction is 57.27%, what is the value of 𝑋?

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