Thanks, so can you fudge the numbers to a certain extent? And what if the stochiometric ratios don’t match up for like a qualitative experiment but you just want to convey the ‘trend’, do you still get penalised?
Well for HSC experiment I can't really think of any that have requirement of meeting the molar ratios, like for instance when you do fermentation you will always end up adding way more glucose than you actually use because the yeast dies when ethanol concentration goes too high, bromine water experiment you add like 2 drops of bromine water. So yeah it doesn't really matter. Here's an example of how you should structure methods:
For bromine water experiment:
1) In a fume cupboard with absence of UV light add 2 mL of hexane and hexene in separate test tubes using a dropper.
2) Add 5 drops of amber bromine water to each test tube using a dropper and swirl. Observe any colour changes that occur
3) Safely dispose of solutions into a waste beaker.
So some things that I as a marker would be looking for are:
- Conditions (does the specific experiment have some type of conditions that the reaction must take place in. So in the above you can't do this experiment in UV light because then substitution reactions will happen. Other experiments where conditions are important include fermentation where you need anaerobic conditions)
- Quantities (just need to be rough numbers --> literally just check if they are there, doesn't matter how much just can't be anything crazy or unreasonable)
- Equipment that are used (how did you add solutions to the test tube --> dropper, how did measure temperature --> thermometer)
- Colours of compounds sometimes are important in experiments that have colour changes (amber bromine water)
- States what observation you are looking for (in this case observe any colour changes that occur. In other experiments this could be observe if any bubbling occurs, observe change in mass etc)