Chapter 16 Organic Synthesis Flashcards
What are the advantages of heating a reaction?
To overcome the activation energy
To increase the rate of reaction
What are the advantages of heating under reflux?
Prevents substances escaping the flask
Enables liquids to be continuously heated
Prevents volatile compounds evaporating out
What is the use of anti-bumping granules?
Ensures smooth boiling by preventing large bubbles forming and violently bumping against glassware
Which way does water enter a condenser? What must be attached to the tubing of a condenser? Where should the thermometer go?
Water always enters at the lowest point
A burette clamp to prevent water flowing everywhere
At in the intersection of the condenser and top of the flask ONLY FOR DISTILLATION
NEVER REFLUX
What layers can form with organic products, and how can you tell them apart? What can be used to separate them?
Aqueous/ Water layers forming along with the organic product
Add water, the layer which gets bigger is the water layer
A separating funnel
How do you use a separating funnel?
Close the tap and pour the mixture in
Place the stopper and invert several times
Allow time for the layers to settle. Distinguish the organic layer by seeing which grows when adding water
Remove, by eye, the separate layers by opening the tap
Describe how acid impurities are removed
Add Aqueous Na2CO3, shake in the funnel
Hold upside down
Open the tap slowly to release the CO2 gas
How can an organic compound be dried?
An an anhydrous inorganic salt such as MgS04 or CaCl2 which hydrates to remove water
What are the overall methods used to separate and purify organic products?
Separating funnels
Removing acid impurities in the funnel with sodium carbonate
Separate layers
Add an anhydrous salt like anhydrous MgSO4 to the liquid in the conical flask
Decant
Filtration to remove solids
Redistillation at the boiling point
Which reaction condition requires a thermometer?
Only distillation
NEVER REFLUX NEVER
When an organic compound is soluble in water, what will the density be?
The same as water, so 1g/dm3
Where do each of the purification steps take place?
Separating into separate liquids- separating funnel
Removing acid impurities- Separating funnel
Remove water- conical flask (followed by decanting)
Redistilling- distilling equipment
Do you write aqueous when describing concentrated acids for reagents?
No, loses the mark
What would you do if there was drop in a pipette?
Do not remove it
Volumetric pipettes are calibrated to have the small drop remaining due to surface tension
Why does water enter the lower point in condensers?
More efficient cooling
Prevents air bubbles
