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Comparing Two Bicarbonate Powders by Mass 4 questions
Comparing Two Bicarbonate Powders by Mass
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A classroom model compares pure sodium bicarbonate, NaHCO3, and pure potassium bicarbonate, KHCO3. Each bicarbonate formula unit can produce one CO2 molecule when it reacts completely. The model supplies enough acid for both samples and collects all the CO2.
| Powder | Sample mass (g) | Molar mass used (g/mol) |
|---|---|---|
| NaHCO3 | 8.40 | 84.0 |
| KHCO3 | 8.40 | 100.0 |
Question 1
Which sample is predicted to produce more moles of CO₂?
- NaHCO₃ only
- KHCO₃ only
- They produce equal amounts.
- The sample masses prevent a comparison.
Question 2
Calculate the predicted moles of CO₂ from each sample.
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The display wants the same CO2 output as the original sodium bicarbonate sample but uses only potassium bicarbonate in a repeat.
Question 3
Calculate the potassium bicarbonate mass needed to give that output.
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The class also tests an 8.40 g blend. It contains equal masses of the two powders. The class uses excess acid and captures all the gas.
Question 4
A student predicts that the blend will give the same amount of CO₂ as the pure sodium bicarbonate sample. Calculate the expected output from the blend and use it to evaluate the claim.
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