Home > Subjects > Chemistry > Level 2 > 2.1 Quantitative analysis > Key tips
- Subject: Chemistry
- AS: 91161
- Level: 2
- Credits: 4
- Internal
Chemistry 2.1 Carry out quantitative analysis
Key tips
- Accuracy when carrying out your titration is extremely important. Your average titre will be compared to a value that your teacher will determine by carrying out the titration themselves. If you are careless when carrying out your titration, you will limit your achievement.
- Make sure you read the burette to two decimal places and record two decimal places for all your readings. The smallest gradations on a burette are 0.1 mL but you can estimate the second decimal place, based on where the bottom of the meniscus lies between two 0.1 marks on the burette. A higher level of accuracy is gained if you read a burette, for example, to 0.05 mL or 0.02 mL, rather than just 0.1 mL. Consequently, the average titre will then be of greater accuracy too. Also, if your burette reading is 14.00mL, do not abbreviate it to 14 as this decreases the accuracy of your reading.
- Record your titration data systematically using a table that includes spaces for initial and final titre values. Make sure units are clearly shown.
- When carrying out calculations, show all working in a systematic and logical way. Include units.
- There are two main approaches to rounding, both of which are acceptable. You can round your answers to 3 significant figures at each step of the calculation, and use the rounded figure in the next step. Or you can record a rounded answer at each step, while leaving the unrounded answer in your calculator and using this in subsequent steps of the calculation, leaving rounding to the end. The most important thing is that the final answer is rounded to 3 significant figures.
- Ask yourself if your final answer makes sense. If you have made an error in your calculation, often the final answer will be way too big or way too small. If it looks wrong, it probably is! Go back and check.
