Alkanes have the general molecular formula C_nH_2n+2. Thus, when n= 1, the alkane is CH₄, when n=2, the alkane is C₂H₆ etc. If an alkane has a molar mass between 140 and 150, this alkane is ________.

Question

Quizplus · Accepted Answer

For n = 1, the molar mass is 12+1+(1*1)=14. For n = 2, the molar mass is (12+1)*2+(1*6)=30. Generalizing this, for n, the molar mass is (12+1)*n+(1*(2n+2)). So, for an alkane with molar mass between 140 and 150, we can write the equation: (12+1)*n+(1*(2n+2)) = 140 to 150 Simplifying, 13n + 2 = 20 to 23 11 ≤ n ≤ 15 So, when n = 11, the molar mass is 146, and when n = 12, the molar mass is 158 which is beyond the given range. Therefore, the only possible answer is option C, i.e., C₁₀H₂₂.

Alkanes Have the General Molecular Formula CnH2n+2

Alkanes Have the General Molecular Formula C_nH_2n+2