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Finding a Missing Ion Count in a Mixture 4 questions
Finding a Missing Ion Count in a Mixture
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A teaching model combines two ionic solids. Each solid contains the negative ion X-. Solid P contains M2+ and X-, and solid Q contains N+ and X-. The solids are electrically neutral. The model reports the ions that came from both solids together.
| Ion | Count |
|---|---|
| M2+ | 12 |
| N+ | 8 |
| X- | Hidden |
Question 1
How many X⁻ ions must appear in the combined record?
- 20
- 24
- 32
- 40
Question 2
How many X⁻ ions in the combined record came from P? Explain using the formula of P.
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The model makes a second neutral mixture. It replaces four M2+ ions with four N+ ions by changing the amounts of the two solids. The same total number of positive ions remains.
Question 3
Predict the X⁻ count in the second mixture. Show your reasoning.
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Question 4
Explain why counting the total number of positive ions cannot by itself predict the negative-ion count in both mixtures.
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