2 Alkanes Alkenes Alkynes

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Naming hydrocarbons : 

Naming hydrocarbons Alkanes, Alkenes, and Alkynes

As simple as it gets : 

I scoured the internet and was unable to find a site that would teach this in simple enough terms. Here are the very basics. As you know from earlier in the class, alkanes are saturated hydrocarbons. The carbons contain the maximum number of hydrogen atoms possible in an alkane. But there are other hydrocarbons. As simple as it gets

Naming alkanes : 

Since the number of hydrogens depends on the number of carbons, alkanes are named by the number of carbons present. See right. Just like with binary molecular, a prefix system is used. Naming alkanes

Naming alkanes : 

As was noted in an earlier class the number of hydrogen atoms is equal to twice that of the carbons plus 2. If a hydrocarbon is not saturated there are other rules and suffixes that must be applied. Naming alkanes

Naming Alkenes : 

For reasons that we will explore next semester, alkenes have two fewer hydrogen atoms than do alkanes. Note the generic formula for an ALKANE: CxH2x+2 The formula for an ALKENE is: CxH2x The number of hydrogen atoms is simply double the number of carbons. Easy enough! Naming Alkenes

Naming alkenes : 

Again, the number of carbons determines the number of hydrogen atoms, just like in an alkane. But instead of doubling and adding two you merely double and call it quits. Note the “ene” suffix Naming alkenes

So what’s the difference : 

If you encountered the word “pentane” you would know instantly from the “pent” that you required five carbon atoms in your molecule. Next you would note the “ane” suffix which indicates that the number of hydrogen atoms is double that of your carbons plus two. 5*2+2=12 Hence the formula is C5H12 So what’s the difference

So what’s the difference : 

If you encountered the word “pentene”, again you would know instantly from the “pent” that you required five carbon atoms in your molecule. However when you noted the “ene” you would merely double the number of carbon atoms to determine the number of hydrogen atoms. 5*2=10 Hence the formula is C5H10 So what’s the difference

Side by side comparison : 

Propane “Prop” = C3 “ane” = H(2x+2) x=32*3+2=8 C3H8 Side by side comparison Propene “Prop” = C3 “ene” = H(2x) x=32*3=6 C3H6

Naming Alkynes : 

Again, for reasons that we will explore next semester, alkynes have four fewer hydrogen atoms than do alkanes and two fewer hydrogen atoms than do alkenes. Note the generic formula for an ALKYNE: CxH2x-2 If you can name an alkane and alkene naming an alkyne is no much different. Simply double your carbon atoms and take away two to determine the hydrogen count. Naming Alkynes

Naming alkenes : 

Yet again, the number of carbons determines the number of hydrogen atoms, just like in an alkane and alkene. But instead of doubling and adding two you double and subtract two. Naming alkenes

Side by side comparison : 

Nonane “Non” = C9 “ane” = H(2x+2) x=92*9+2=10 C9H20 Side by side comparison Nonyne “Non” = C9 “yne” = H(2x-2) x=92*9-2=16 C9H16