Evaluative Practical F326
- Created by: Labake
- Created on: 17-10-14 20:23
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- Evaluative Practical F326
- "You will be evaluating different methods of determining a formula"
- Thermal Decomposition
- E.g. Carbonates or hydrated salts forming oxides and gases (Redox)
- Can work outmass , mol and ratio of oxide to carbonate (x)
- Heating
- Hydrated salts observations= Water vapour, condensation, gas, glowing splint relights, white solid at end
- E.g. Carbonates or hydrated salts forming oxides and gases (Redox)
- Dehydration
- Gravimetric method
- When determining x in hydrated salts
- Weighing hydrated- heating to anhydrous-- heat to constant mass for accuracy and precision
- Weigh anhydrous mass and take from hydrated for mol of H20 etc
- Heat to constant mass mean keep reheating hydrated salt and reweighing till constant mass reached
- May overheat and decompose, moles increase and Mr decreases
- Weigh anhydrous mass and take from hydrated for mol of H20 etc
- Weighing hydrated- heating to anhydrous-- heat to constant mass for accuracy and precision
- When determining x in hydrated salts
- Gravimetric method
- Titration
- Issues
- Accuracy problem when making the solution
- Dissolving the solid then rinsing the equipment
- If done incorrectly (e.g. solid left on equipment) moles decrease and Mr increases
- Conc. increase= moles increase
- Moles of smaller ratio will decrease
- Mr of smaller ratio increases
- Moles of smaller ratio will decrease
- More decimal places on balance= smaller % error
- Conc. increase= moles increase
- If done incorrectly (e.g. solid left on equipment) moles decrease and Mr increases
- Dissolving the solid then rinsing the equipment
- Accuracy problem when making the solution
- Issues
- Precipitation
- Aqueous +aqueous (e.g.carbonate or halogen formed as solid) forming a solid precipitate
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