Density Of A Liquid - Casio fx-7400G PLUS Booklet

EC-1 Density of a Liquid
In exercises that involve measurements, the most common approach is to perform calculations
and draw graphs based on measurement results, and then to study tendencies, estimated
values, and other factors. This exercise is a practical application of a physical chemistry
exercise (physical measurement) using the graphic calculator.
Among physical chemistry exercise types are those that measure the physical properties of
liquid. These types of exercises measure density, viscosity, surface elasticity, index of refraction,
angle of rotation, etc. All such exercises measure physical properties as the concentration of a
liquid changes, and graphs the changes in order to make estimates and to study various
properties affected by the changes.
The practical exercise presented here shows how to graph measurement results.
Exercise
Measuring the Density of a Liquid
Solutions of ethanol and water are prepared in concentrations of 0, 20, 40, 60, 80, and 100
wt%. Each sample is poured into a specific gravity flask, its mass is measured under
constant temperature, and the density of each is calculated. Results are used to create and
study a concentration – density curve.
Results (Example)
Table 1 — Measurement Results
Sample Ethanol Concentration
Number
1 0 (Water)
2
3
4
5
6
When the specific gravity flask mass m
(g/cm 3 ), the volume of the specific gravity flask is:
m
1
V =
Sample solution density ρ (g/cm
m
2
ρ =
Graphic Calculator Operation
1-1. Data Input
From the Main Menu, enter the STAT Mode, and then input
the concentration values into List 1 (0 to 100).
Also, input the measurement results (mass) into List 2.
Specific Gravity Flask +
(wt%)
Sample Mass m
21.0233
20 20.6962
40 20.3251
60 19.8745
80 19.3807
100 18.8342
– m 21.0233 – 11.0205
0
=
ρ 0.9940
w
3 ) is the following:
– m m – m
0 2 0
= ρ
V m – m
1 0
Table 2 — Calculation Results
Ethanol Concentration
(g) (wt%)
2
= 11.0205 (g) and the density of water ρ
0
= 10.063 [cm
m – 11.0205
2
=
w
21.0233 – 11.0205
– 32 –
Density ρ
(g/cm 3 )
0 0.9940
20 0.9615
40 0.9246
60 0.8798
80 0.8308
100 0.7765
3 ]
0.9940 [g/cm 3 ]
is 0.9940
w