Question

The following Table 1 gives the density of water at different temperatures. Use this information to complete the data and calculations in Table 2 and calibrate the true volume of a 10 mL pipet. Please include units and round off to the correct significant figures/decimal places at each step. 1. Table 1 Density Density Temp. "C Temp. C g/mL g/mL 0.99780 22 18 0.99865 0.99757 0.99844 23 19 0.99733 0.99823 24 20 0.99708 21 0.99802 25 Table 2 Trial 3 Trial 2 31.7991 g Trial 1 31.9153 g Mass of container & 31.6538 g water 21.6799 g 21.9211 g 21.8002 g Mass of empty container Mass of water 21°C 19°C 20°C Temp. of water Density of water Volume of water True volume of pipet Average value for volume of pipet

Answer 1

Trial 1:

Step 1: Calculation of mass of water

Mass of water = mass of container & water - mass of container

= 31.6538 - 21.6799

= 9.9739 g

Step 2: Calculation of volume of water.

density = mass / volume

Volume = mass / density. (Given density of water at 19⁰c is 0.99844 g/ mL)

Volume of water = 9.9739 g / 0.99844 g/mL

= 9.9894 mL.

True volume of pipet = 9.9894 mL.

Trial 2:

Step 1: Calculation of mass of water

( Procedure is same as above mentioned)

Mass of water = 31.7991 g - 21.8002 g

= 9.9989 g

Step 2: Calculation of volume of water

Volume = mass / density

= 9.9989 g /0.99823 g/mL

Volume = 10.0166 mL

TreT volume of pipet = 10.0166 mL.

Trial 3 :

Step 1: Calculation of mass of water

Mass of water = 31.9153 g - 21.9211g

Mass of water = 9.9942 g

Step 2: Calculation of volume of water

Volume of water = Mass of water/ density of water at 21⁰c

Volume of water = 9.9942 g/ 0.99802 g/mL

Volume of water = 10.014 mL

True volume of pipet = 10.014 mL.

Average value for volume of pipet = sum of the volume of water in the three trials divided by three.

Average value for volume of pipet = 9.9894 mL + 10.0166 mL + 10.014 mL / (3).

Average value for volume of pipet = 10.00667 mL

After rounding off

Average value for volume of pipet = 10 mL.