International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

Disable ads (and more) with a membership for a one time $4.99 payment

Prepare for the IGCSE Chemistry Exam with our comprehensive quiz. Practice with multiple choice questions and detailed explanations to boost your understanding. Excel in your examination journey!

Practice this question and more.

What is the structural formula for ethene?

CH2=CH2
C2H4
CH3-CH=CH-CH3
CH2=CH-CH2-CH3

The correct answer is: CH2=CH2

Ethene, also known as ethylene, is an alkene and has the molecular formula C2H4. Its structural formula displays the arrangement of atoms and the type of bonds between them. The correct structural formula for ethene is represented as CH2=CH2, indicating that two carbon atoms are double-bonded to each other, with each carbon atom also bonded to two hydrogen atoms. This structural representation shows that there is a carbon-carbon double bond, making ethene the simplest alkene. The presence of this double bond is a defining characteristic of alkenes, which differentiates them from alkanes that only have single bonds. While C2H4 indicates the molecular composition of ethene, it does not specify how the atoms are arranged or bonded. The other choices either depict more complex structures, such as alkanes and longer carbon chains, or do not represent the simple double bond configuration found in ethene. Therefore, the structural formula CH2=CH2 accurately illustrates the essential features of ethene as it highlights the double bond crucial for its chemical behavior and properties.