Criterion C asks you to turn raw results into a justified conclusion. In chemistry that means careful tables and graphs, a calculation you can follow, and an honest account of the experiment’s limits.
Clear tables and graphs with units, labels and any calculations shown.
You describe the pattern with numbers and explain it using science.
You say whether the evidence supports your hypothesis and how far.
You link specific weaknesses in the method to their effect on the results.
Realistic changes that would fix the weaknesses you found, or the next question to test.
A little of the criterion is addressed. Ideas are basic, partly missing, or not linked to the task.
The main points are there but thin. Some explanations are correct; links to the task or evidence are incomplete.
Mostly accurate, well explained and consistently tied to the task, with only small gaps.
Detailed, precise and justified throughout, with ideas connected and applied to new situations or evidence.
A plain-language guide only. Your teacher marks against the official IB level descriptors.
Evaluate an experiment measuring the temperature rise when a fuel heats water.
Some heat was lost so the results are not accurate. Use a better thermometer.
The temperature rise was lower than the value calculated from the data book because much of the heat from the burning fuel warmed the air and the beaker rather than the water. This makes the calculated energy per gram lower than it should be. Adding a draught shield and a lid, and using a copper calorimeter, would reduce the loss and bring the result closer to the accepted value.
Criterion C is Processing and evaluating. It is marked out of 8 across 5 strands (C.i, C.ii, C.iii, C.iv, C.v). Criterion C asks you to turn raw results into a justified conclusion. In chemistry that means careful tables and graphs, a calculation you can follow, and an honest account of the experiment’s limits.
Show one worked example of each calculation, with units, so a reader can follow the method. For rate data, plot the graph, draw a line or curve of best fit and describe its shape in words and numbers. Use chemical reasoning in the interpretation, such as more collisions per second at higher concentration.
Reporting a calculated value to far more significant figures than the measurements allow. Describing results as good or bad instead of describing the trend. Saying the experiment was unfair without naming the uncontrolled variable.
Written by CritABCD for study and revision, in our own words. The official MYP Chemistry guide and assessment criteria are published by the International Baccalaureate. Official IB guide ↗