Question

1. Which item of volumetric equipment should be use to: a. measure approximately 10mL of solution? b. measure 10.10mL of solution?
2. Why is it necessary to rinse a buret or pipet with the liquid to be measured?
3. Indicate whether the following errors are random or systematic.
a. The graduation mark on a pipet is incorrect by +0.11mL.
b. Three students read a buret and obtain values of 25.10, 25.12, and 25.09ml.
c. The balance is not zeroed and a series of weighings are made with the balance initially at 0.0200 g. 

Answer 1

1. (a) To measure approximately 10 mL of solution we can use Graduated Cylinders, which used where volume is not required very exactly.

(b) We can use the measuring pipets to measure 10.10 mL.

2. To rinse the buret and pipet reduce the concentration variation by removing the solvent stuck to the wall of buret and pipet.

3. We know the random error occurs due to the inability to reproduce the measured the data again, it can be reduced when the number of measurements increases and systematic error are the error which we can not reduce by increasing the measurements. So, we can say the systematic error is a permanent error.

Now move to answer the question:

(a) Systematic Error (We can not neglect this error by statistically, this is permanent error)

(b) Random Error ( Here the difference in the values are small, we can reduce them by taking more data)

(c) Systematic Error (Permanent Error)