Question

1. choose the best answer.

when an ionic compound is dissolved in water it separates into separate ions, which is called ____.
○ a dissociation
○ a synthesis reaction
○ a precipitate
○ a gas bubble

1. choose the best answers.

which arrow shows a catalyst has been added?
○ elec →
○ pd →
○ δ →

Explanation:

Question 16

To solve this, we analyze each option:

• a dissociation: Dissociation is the process where an ionic compound breaks into ions when dissolved in water. This matches the description.
• a synthesis reaction: A synthesis reaction is combining substances, not separating into ions. Eliminate.
• a precipitate: A precipitate is a solid formed from a reaction, not ion separation. Eliminate.
• a gas bubble: A gas bubble is related to gas formation, not ion separation. Eliminate.

In chemical equations, a catalyst is often written above the reaction arrow. Among the options:

• "elec" likely represents electricity (electrolysis), not a catalyst.
• "Pd" (Palladium) is a common catalyst, so the arrow with "Pd" indicates a catalyst was added.
• The triangle ($\Delta$) represents heat, not a catalyst.

Answer:

A. a dissociation

Question 17