Drawing and naming the alcohols
4 marks · NormalTable 1 shows information about some alcohols.
| Name | Molecular formula | Structural formula |
|---|---|---|
| methanol | CH4O | CH3OH |
| ethanol | C2H6O | CH3CH2OH |
| ? | C3H8O | CH3CH2CH2OH |
| butan-2-ol | C4H10O | CH3CHOHCH2CH3 |
Name the alcohol in Table 1 with the molecular formula C3H8O and the structural formula CH3CH2CH2OH.
How many carbon atoms are present in ethanol?
Write the displayed formula for methanol, showing all bonds.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) propan-1-ol · must show Accept 'propanol'
(b) 2
(c) — · must show All bonds shown: H—C—O—H
Must show: Displayed formula for methanol must show C–O–H with all bonds, including the O–H bond
Also accept: For part a: Accept 'propan-1-ol' or 'propanol'
Common mistakes: Omitting the O–H bond; Incorrect structure
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly names 'propan-1-ol' (accept 'propanol')
B1 (b) · 1 mark · States that ethanol contains 2 carbon atoms
B1 (c) · 2 marks · Draws displayed formula for methanol showing C–O–H with all bonds (CH3–O–H displayed or equivalent)
Worked solution
a) The alcohol is propan-1-ol (or propanol).
b) Ethanol has 2 carbon atoms.
c) Displayed formula for methanol: