Question

given the value of n write the names and molecular formulas of strain chain alkanes​

Answer 1

Answer:

Alkanes are hydrocarbons in which the carbon atoms are held together by single bonds. Their general formula is CnH2n+2 for molecules which do not contain ring structures.

Alkanes are in some respect the most boring of the organic compounds, since they are unreactive (mostly) towards acids, bases, oxidizing agents, reducing agents, and most of the other reagents that organic chemists have in their arsenals. On the other hand, alkanes are important for their ability to undergo combustion with molecular oxygen (O2): alkanes of various lengths are the major components of the hydrocarbon fuels that we burn for energy, whether for cooking (methane, propane, butane) or for transportation (gasoline, diesel fuels):

CnH2n+2 + (3n+1)/2O2 ® nCO2 + (n+1)H2O + energy

Straight-Chain and Branched Alkanes

The straight-chain (normal) and branched alkanes have the general formula CnH2n+2. The molecules consist of either straight chains of carbon atoms, connected one after the other, with the appropriate number of hydrogen atoms on each carbon, or as branched chains of carbon atoms having carbon substituents (alkyl groups) attached at various points along the chain.

Straight-chain alkanes are named by using a stem that indicates the number of carbon atoms (meth = 1 C, eth = 2 C's, prop = 3 C's, etc.) to which is added the suffix -ane, indicating that the molecule is an alkane (that is, that the carbon atoms are all connected by single bonds). Thus, the word "propane" indicates that there are three carbon atoms in the chain, all connected by single bonds.

Number of

Carbons Stem

1 meth-

2 eth-

3 prop-

4 but-

5 pent-

6 hex-

7 hept-

8 oct-

9 non-

10 dec-

Answer 2

We previously introduced the three simplest alkanes—methane (CH4), ethane (C2H6), and propane (C3H8) and they are shown again in Figure 12.3.112.3.1.

The flat representations shown do not accurately portray bond angles or molecular geometry. Methane has a tetrahedral shape that chemists often portray with wedges indicating bonds coming out toward you and dashed lines indicating bonds that go back away from you. An ordinary solid line indicates a bond in the plane of the page. Recall that the VSEPR theory correctly predicts a tetrahedral shape for the methane molecule (Figure 12.3.212.3.2).