Write down ONE controlled variable for this investigation.
About this question
Question 3.3 of Technical Sciences Grade 12 Paper 2, NSC Preparatory Examination (Eastern Cape DoE, September 2025). It tests the Term 2 ATP topic Organic Chemistry Structure.
- TermTerm 2
- ATP topicOrganic Chemistry Structure
- PaperPaper 2
- Marks1 mark
Learners investigated the melting points of various organic compounds.
| Compound | Name | Melting point (\(^\circ\text{C}\)) |
|---|---|---|
| P | Ethanoic acid | \(16{,}6\) |
| Q | Ethanol | \(-114{,}1\) |
| R | 1-Chloroethane | \(-138{,}7\) |
| S | Ethane | \(-182{,}8\) |
Chain length (the number of carbon atoms).
More Questions On Organic Chemistry Structure
INCREASE.
Electrode X is the cathode, where reduction takes place: \(\text{Cu}^{2+}\) gains electrons and copper metal is deposited on X, so its mass goes up.
An electrolytic cell is an electrochemical cell in which electrical energy is converted to chemical energy.
Carboxylic acids (ethanoic acid, compound P, melts at \(16{,}6\ ^\circ\text{C}\)).
The lead half-cell is the cathode (it is the positive electrode), so X is the anode.
\[ E^\theta_{cell} = E^\theta_{cathode} - E^\theta_{anode} \]\[ 0{,}63 = -0{,}13 - E^\theta_{X} \]\[ E^\theta_{X} = -0{,}76\ \text{V} \]From the table of reduction potentials this is zinc.
X is zinc (\(\text{Zn}\)).