Physics Q . ..?

Question

An undergraduated thermometer attached to a centimeter scale reads 13 cm in pure melting ice and 38 cm in steam at 1 atm. When the thermometer is placed in a certain freezing mixture it reads 11.5 cm. When the thermometer is placed in pure boiling ethanoic acid it read 42.5 cm. What is:

a. the temp of the freezing mixture?

b. the boiling temp of pure ethanoic acid?

Answer 1

It looks like the range from 0 to 100 degrees is covered by a span of 25cm, so there are 4° per centimeter.

11.5 cm is 1.5 cm below zero, or -6°

42.5 cm is 4.5 cm above the boiling point of water, so it is (100° + 4.5 × 4°) 118° (checked it and this is indeed the boiling point of ethanoic acid)

Answer 2

38 cm - 13 cm = 25 cm

a)

100 deg. Celsius = 25 cm

x deg. celsius = 1.5 cm (13 cm - 11.5 cm)

Find x:

x = 100 * 1.5 / 25 cm

x = 6

x = -6 deg C

b)

100 deg C = 25 cm

x deg C = 4.5 cm (42.5 cm - 38 cm)

Find x:

x = 100 * 4.5 / 25 cm

x = 18

x = 118 deg C