Organic Constructive ResponsesDon’t focus on how hard something is, put your effort towards finding a solution.

Ethene and hydrogen can react at a faster rate in the presence of the catalyst platinum. The equation below represents a reaction between ethene and hydrogen.

1) State the number of electrons shared between the carbon atoms in one molecule of the reactant ethene.

2) Explain why the reaction is classified as an addition reaction.

Jan 2014#59-61

Double bond represents 4 shared electrons.

The hydrogen combined with the ethene to produce only one product (ethane).

Table sugar, sucrose, is a combination of two simple sugars, glucose and fructose. The formulas the right represent these simple sugars.

3) Identify the functional group that appears more than once in the fructose molecule.

4) Explain, in terms of atoms and molecular structure, why glucose and fructose are isomers of each other.

Jan 2014#64-65

Glucose and fructose both have the formula C6H12O6

“-OH”

Rubbing alcohol, typically composed of 2-propanol and water, is a product available at most pharmacies and supermarkets. The boiling point of 2-propanol is 82.3°C at standard pressure.

5) Explain, in terms of electronegativity differences, why a C-O bond is more polar than a C-H bond.

6) Identify a strong intermolecular force of attraction between an alcohol molecule and a water molecule in the solution.

7) Explain, in terms of charge distribution, why a molecule of the 2-propanol is a polar molecule.

8) Draw the structural formula for 2-propanol. Jan 2014#71-75

C-O has a 0.8 electronegativity difference, whereas the C-H is 0.4, thus C-O is a more polar covalent bond.

Hydrogen bonding (dipole attraction)

The “O” in 2-propanol is slightly negative where the “H” is slightly positive.

There are several isomers of C6H14. Theformulas and boiling points for two ofthese isomers are given in the table to the right.

9) Identify the homologous series to which these isomers belong.

10) Write the empirical formula for isomer 1. 11) Explain, in terms of intermolecular forces, why isomer 2 boils at a lower temperature than isomer 1.

Jun 2013#63-65

Alkane

C3H7

Due to symmetry, the second isomer is more of a nonpolar molecule thus is has a weaker intermolecular forces of attraction.

The equation below represents the reaction between 1-butene and bromine to formthe compound 1,2-dibromobutane, C4H8Br2.

12) Explain, in terms of bonding, why the hydrocarbon reactant is an unsaturated hydrocarbon.

13) Write the empirical formula for the product.

Jan 2013#59-61

1-butene has a double bond, thus it is considered to be unsaturated.

C2H4Br

In one method of making bread, starch is broken down into glucose. Zymase, an enzyme present in yeast, acts as a catalyst for the reaction in which the glucose reacts to produce ethanol and carbon dioxide. The carbon dioxide gas causes the bread dough to rise. The balanced equation below represents the catalyzed reaction.

C6H12O6(aq) 2CH3CH2OH(aq) + 2CO2(g)

14) Identify the type of organic reaction represented by this equation.

15) Identify the functional group in an ethanol molecule.

Jan 2013#83-85

zymase

fermentation

“-OH”

One type of soap is produced when ethyl stearate and sodium hydroxide react.The soap produced by this reaction is called sodium stearate. The other product of the reaction is ethanol. This reaction is represented by the balanced equation below.

16) Identify the type of organic reaction used to make soap.

17) To which class of organic compounds does ethyl stearate belong?

18) Identify the two types of bonds in the compound sodium stearate.

Jun 2012#79-81

saponification

ester

covalent and ionic

Two hydrocarbons that are isomers of each other are represented by the structuralformulas and molecular formulas below.

19) Explain, in terms of bonds, why these hydrocarbons are unsaturated.

20) Explain, in terms of structural formulas and molecular formulas, why these hydrocarbons are isomers of each other.

Jan 2012#58-59

Hydrocarbons with double or triple bonds are considered unsaturated.

Both have the same number of atom (C5H8), however they have different structures.

Natural gas is a mixture that includes butane, ethane, methane, and propane. Differences in boiling points can be used to separate the components of natural gas. The boiling points at standard pressure for these components are listed in the table to the right.

Jan 2011#69-70

21) Identify a process used to separate the components of natural gas.

22) List the four components of natural gas in order of increasing strength of intermolecular forces.

Fractional distillation

Methane (easiest to boil), ethane, propane, butane (most difficult to boil)

A reaction between bromine and a hydrocarbon is represented by the balancedequation below.

23) Identify the type of organic reaction.

24) Write the name of the homologous series to which the hydrocarbon belongs.

Jun 2011#64-65

Addition, halogenation or bromation

Alkene (note: hydrocarbon refers to a molecule with only hydrogen and carbon)

In one industrial organic reaction, C3H6 reacts with water in the presence of a catalyst. This reaction is represented by the balanced equation below.

25) Explain, in terms of bonding, why C3H6 is classified as an unsaturated hydrocarbon.

26) Write the IUPAC name for the organic reactant.

27) Identify the class of compound to which the product of the reaction belongs.

Jan 2011#78-80

C3H6 has a double bond in it, thus it is unsaturated.

propene

The product is an alcohol

Gasoline is a mixture composed primarily of hydrocarbons such as isooctane, which is also known as 2,2,4-trimethylpentane. Gasoline is assigned a number called an octane rating. Gasoline with an octane rating of 87 performs the same as a mixture that consists of 87% isooctane and 13% heptane. An alternative fuel, E-85, can be used in some automobiles. This fuel is a mixture of 85% ethanol and 15% gasoline.

28) State the octane rating of a gasoline sample that performs the same as a mixture consisting of 92% isooctane and 8% heptane.

29) Identify the functional group in a molecule of ethanol.

30) Draw a structural formula for 2,2,4-trimethylpentane.

Aug 2010#67-69

Rating of 92

-OH

Glycine, NH2CH2COOH, is an organic compound found in proteins. Acetamide,CH3CONH2, is an organic compound that is an excellent solvent. Both glycine andacetamide consist of the same four elements, but the compounds have different functional groups.

31) Identify one functional group in a glycine molecule.

32) In the space in your answer booklet, draw a structural formula for acetamide.

Jun 2010#57-58

“N” or “COOH”

The formula to the right represents a hydrocarbon.

33) Identify the homologous series to which this hydrocarbon belongs.

34) Explain, in terms of carbon-carbon bonds, why this hydrocarbon is saturated.

35) Draw a structural formula for one isomer of this hydrocarbon.

Jan 2010#58-60

alkane

Organic that contain single bonds between the carbons are considered saturated.

Biodiesel, a fuel alternative, is produced by reacting vegetable oil with CH3OH. Methyl palmitate (C15H31COOCH3), a compound found in biodiesel, is made from soybean oil. One reaction of methyl palmitate with oxygen is represented by the balanced equation below.

2C15H31COOCH3 + 49O2→34CO2 + 34H2O + energy

36) Write an IUPAC name for the compound that reacts with vegetable oil to produce biodiesel.

37) Explain, in terms of both atoms and molecular structure, why there is no isomer of CH3OH.

38) Identify the class of organic compounds to which methyl palmitate belongs.

39) Identify the type of organic reaction represented by the balanced equation.

Aug 2009#68-71

methanol

There is only one structure for a molecule with 1C, 4H and an O.

ester

combustion

Bond energy is the amount of energy required to break a chemical bond. The table to the right gives a formula and the carbon-nitrogen bond energy for selected nitrogen compounds.

Aug 2009#59-62

40) Describe, in terms of electrons, the type of bonding between the carbon atom and the nitrogen atom in a molecule of methanamine.

41) State the relationship between the number of electrons in a carbon-nitrogen bond and carbon-nitrogen bond energy.

42) Explain, in terms of charge distribution, why hydrogen cyanide is polar.

Covalent sharing 2 electrons.

The more electrons in the bond, the more energy needed to break the bond

Due to bonding and symmetry, the nitrogen side of hydrogen cyanide is slightly negative, whereas, the hydrogen side is more positive.

Diethyl ether is widely used as a solvent.

43) Draw the structural formula for diethyl ether

44) Draw the structural formula for an alcohol that is an isomer of diethyl ether.

June 2003#55-56

or

Many artificial flavorings are prepared using the type of organic reaction shown below.

45) What is the name of this organic reaction?

46) To what class of organic compounds does reactant 2 belong?

47) Draw the structural formula of an isomer of reactant 2.

Jan 2004#68-70

esterification

alcohol

or

The incomplete equation below represents an esterification reaction. The alcoholreactant is represented by X.

48) What is the functional group for the acid?

49) Write an IUPAC name for the reactant.

50) In the space in your answer booklet, draw the structural formula for the alcohol represented by X.

Aug 2007#64-66

“-COOH”

ethanoic acid (aka acetic acid)

The compound 1,2-ethanediol can be mixed with water. This mixture is added toautomobile radiators as an engine coolant. The cooling system of a small van contains6690 grams of 1,2-ethanediol. Some properties of water and 1,2-ethanediol are given in the table below.

51) Identify the class of organic compounds to which 1,2-ethanediol belongs.

52) State, in terms of molecular polarity, why 1,2-ethanediol is soluble in water.

Jan 2008#66-67

alcohol

The “OH” functional groups are very much like the polar regions of water, thus the alcohol will form hydrogen bonds with water.

Given the balanced equation for an organic reaction between butane and chlorine thattakes place at 300.°C and 101.3 kilopascals:

C4H10 + Cl2 → C4H9Cl + HCl

53) Identify the type of organic reaction shown.

54) In the space in your answer booklet, draw a structural formula for the organic product.

Jun 2006#61-62

substitution, halogenation or chlorination

or

The hydrocarbon 2-methylpropane reacts with iodine as represented by the balanced equation to the right. The boiling point of 2-methylpropane is lower than the boiling point of 2-iodo-2-methylpropane.

Jun 2008#59-61

55) To which class of organic compounds does this organic product belong?

56) Explain, in terms of bonding, why the hydrocarbon 2-methylpropane is saturated.

57) In terms of both molecular polarity and intermolecular forces, explain the difference in the boiling points of 2-methylpropane and 2-iodo-2-methylpropane.

halocarbon

Saturated molecule will have single bonds between all carbon atoms.

2-iodo-2-methylpropane is more polar, thus will tend to form hydrogen bonds (thegreater attraction will cause in increase in boiling point).

The equation below represents the reaction between butanoic acid and an unidentifiedreactant, X.

58) Identify the type of organic reaction represented by the equation.

59) Write the molecular formula of the organic product in the equation.

60) In the space in your answer booklet, draw a structural formula for the unidentified reactant, X, in the equation.

Aug 2008#60-62

esterification

C6H12O2

Ethyl butanoate is an organic compound that contributes to the odor of pineapple. Furthermore, ethyl butanoate is one of the products formed by the reaction of butanoic acid with ethanol.

61) Identify two differences in the structures between a molecule of butanoic acid and a molecule of ethanol. Each of your responses must include both compounds.

62) Identify the type of organic reaction that produces the compound that contributes to the odor of pineapple.

Jan 2009#80-81

a) Butanoic acid has four carbons, whereas ethanol has only 2 carbons. b) Butanoic acid has a “-COOH” functional group, whereas, ethanol has an “-OH” functional group

esterification