Write the structure for the alkane:
molecular mass = 72 u; forms four monochlorination products.
Well since its 72u and its an alkane, I figured out that the formula is C5H12. But what does it mean that it "forms 4 monochlorination products"?
A Cl atom sticks to four separate sites to give four separate products.
The statement "forms four monochlorination products" indicates that when the alkane undergoes chlorination, it can yield four different products with the incorporation of a single chlorine atom in different positions of the molecule.
To determine the possible monochlorination products, we need to consider the different positions in the alkane molecule where a chlorine atom can substitute a hydrogen atom.
For an alkane with the molecular formula CᵦH₂ₙ₊₂ where ᵦ represents the number of carbon atoms and ₂ represents the number of hydrogen atoms, we can determine the total number of hydrogen atoms (H) in the molecule using the formula ₂H = ₂ₙ + ₂.
In this case, the molecular mass is given as 72 u, which is equal to the molecular weight of C5H12. To calculate the number of hydrogen atoms, we can subtract the molecular weight of carbon atoms (C) from the molecular mass and then divide by the atomic weight of hydrogen (H).
The atomic weight of carbon is approximately 12 g/mol, and the atomic weight of hydrogen is approximately 1 g/mol.
((72 u - 5 * 12 g/mol) / 1 g/mol) = 12.
So, the alkane has 12 hydrogen atoms.
Now we can determine the possible monochlorination products by substituting a single hydrogen atom with a chlorine atom in different positions within the alkane molecule.
For an alkane with the formula C5H12, we would create four monochlorination products by substituting one hydrogen atom at a time in each possible position:
1. Chlorination at the first carbon position: C₅H₁₁Cl
2. Chlorination at the second carbon position: C₄H₁₁Cl
3. Chlorination at the third carbon position: C₃H₁₁Cl
4. Chlorination at the fourth carbon position: C₂H₁₁Cl
These are the four possible monochlorination products for the given alkane with the molecular mass of 72 u.