Answered

Knowledge Check

Question 13

In the table below, there are descriptions of an experiment on samples of three different chemical compounds. Decide whether the compound is ionic or molecular if you can. If there is not enough information to decide, choose "can't decide" in the third column.

\begin{tabular}{|c|l|c|}
\hline
Compound & \multicolumn{1}{|c|}{Description} & Ionic or Molecular? \\
\hline
1 &
\begin{tabular}{l}
Compound 1 is a clear liquid with a strong, pleasantly fruity smell. If \\
cooled, it freezes at about [tex]$-10{ }^{\circ} C$[/tex]. In the solid state, it does not \\
conduct electricity.
\end{tabular} & Molecular \\
\hline
2 &
\begin{tabular}{l}
Compound 2 is a yellow solid made up of clusters of needle-like crystals. \\
It's a good electrical insulator when solid, but if crushed and dissolved in \\
water, the solution is a good conductor.
\end{tabular} & Can't Decide \\
\hline
3 &
\begin{tabular}{l}
Compound 3 is a deep red solid with a noticeable, unpleasant smell. It \\
dissolves slightly in water, and a solution of 2 g in 100 mL of water \\
doesn't change the electrical conductivity of the water.
\end{tabular} & Molecular \\
\hline
\end{tabular}



Answer :

GinnyAnswer
Sure, let's analyze the properties of each given compound and determine whether each is ionic or molecular (covalent) based on their characteristics.

### Compound 1
Description:
- Clear liquid with a strong pleasantly fruity smell.
- Freezes at around -10°C.
- Does not conduct electricity in the solid state.

Analysis:
The fact that Compound 1 is a clear liquid with a pleasant smell and has a freezing point of around -10°C suggests that it is an organic compound with low molecular weight, likely a molecular (covalent) compound. The lack of electrical conductivity in the solid state further supports it being molecular, as ionic compounds typically conduct electricity when dissolved in water due to their ions.

Conclusion: Molecular.

### Compound 2
Description:
- Yellow solid made up of clusters of needle-like crystals.
- Good electrical insulator when solid.
- Conducts electricity when crushed and dissolved in water.

Analysis:
The compound's property of not conducting electricity in the solid state but conducting when dissolved in water suggests the presence of ions in solution. This is a characteristic behavior of ionic compounds. However, since we can't be entirely certain without knowing the complete chemical structure or additional information, it might be ambiguous.

Conclusion: Can't decide.

### Compound 3
Description:
- Deep red solid with a noticeable unpleasant smell.
- Dissolves slightly in water.
- Solution of 2 grams in 100 mL of water doesn't change the electrical conductivity of the water.

Analysis:
The slight solubility in water without changing water’s conductivity indicates that no ions are produced in the solution. This typically suggests it is a molecular compound because ionic compounds would dissociate into ions and change the conductivity of the water.

Conclusion: Molecular.

Therefore, according to the analysis:
- Compound 1 is molecular.
- Compound 2 can't be definitively classified without more information.
- Compound 3 is molecular.

Other Questions