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Definition:

Equation

Parameters

Diagram

Calculate Properties of
Solution:
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Parameter

Value

Units

Special
Values

<

Inputs:

D
(diameter)

meterscentimetersmillimetersmicrometersnanometersinchesfeetmilsyardsmileskilometerslightyearsangstrom (ũastronomical unit
(AU)fermi (fm)micron
(um)nautical mile (nmi)parsec (pc)statute mile
(mi)yard (yd)____________________

l
(length)

(AU)fermi (fm)micron
(mi)yard (yd)____________________

R
(resistance)

OhmskiloOhmsMegaOhmsmilliOhmsmicroOhmsnanoOhms____________________

Outputs:

C's (conc.
solute)

grams/liter (g/l)grams/cubic meter
(g/m?)grams/millilitter (g/ml)grams/cubic foot (g/ft?)grams/cubic
inch (g/in?)grams/cup {US, liquid}grams/gallon
(g/gal){US}_________________

C'w (conc.
water)

grams/liter (g/l)grams/cubic meter
(g/gal){US}_________________

C's
(alternate)

grams/liter (g/l)grams/cubic meter
(g/gal){US}_________________

V (volume)

cubic
meter (m?)liter (l)cubic
centimeter (cm?)cubic foot (ft?)cubic inch (in?)cubic yard
(yd?)_________________teaspoon
(tsp)tablespoon (tbsp)cup {US, liquid}pint {US,
liquid}quart {US, liquid}gallon (gal){US}_________________cup {UK}cup {US,
dry}gallon (gal){UK}

ρ
(resistivity)

Ohm-meterskiloOhm-metersMegaOhm-metersmicroOhm-metersmicroOhm-centimetersOhm-centimetersOhm-feet____________________

A
(area)

square
meterssquare centimeterssquare
millimeterssquare micrometerssquare nanometerssquare
inchessquare feetsquare milssquare
yardssquare milessquare
kilometerssquare lightyears____________________

Output
Format:
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Format:

Scientific

Engineering

Fixed

Notes:
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The alternate value for
C'S is obtained from a fit to measured data found here.  This is a fit to
measured data that covers much higher resistivities.  The equation is
log(C's)=(log(1553)-log(ρ))/0.7465, where C'S is in
g/l and ρ is in Ohm-cm.

You should use de-ionized water and
copper electrodes to reduce resistance change over
time.

Example:  Suppose you
want to make a 1000 ohm resistor out of 1" inner-diameter Tygon tubing
with copper electrodes inserted at each end with 1 foot between
electrodes.  The calculator gives C's=19.653 g/l and
C'w= 991.41 g/l.  So, to make one liter of solution, fill
a jar with 991.41 g of water and 19.653 g of
CuSO4*5H2O (or make a smaller batch keeping the same
proportions).  Note:  you could just add the amount,
C's, to one liter of water with negligible error (you have to
do this for the alternate version of C's).  Also, if you
want to make just enough then use the volume (in liters) from the
calculator and multiply this by C's to get the amount of
CuSO4*5H2O you need, then fill with water.

CuSO4*5H2O is
know by several names (copper sulfate, cupric sulfate, cupric sulfate
pentahydrate,...) and appears as blue crystals.

Calculator assumes solution
temperature of 20oC (68oF).  Actual resistance
is a function of water
temperature.

In the table below, the left three
columns are data from the CRC Handbook of Chemistry and Physics.  H%
is the percent of hydrate (CuSO4*5H2O) by weight in
the solution.  D204 is the relative density of
the solution at 20oC compared to water at 4oC.
γ is the specific conductance at 20oC.  The right three
columns are derived from the others for this
calculator.

H%

[by wt.]

D204

g

[mS/cm]

Cs'

[g/l]

CW'

[g/l]

r

[W-m]

1.56

1.0085

5.4

15.7

992.8

1.852

3.13

1.0190

9.3

31.9

987.1

1.075

4.69

1.0296

12.8

48.3

981.3

0.781

6.26

1.0403

16.0

65.1

975.2

0.625

7.82

1.0511

19.0

82.2

968.9

0.526

9.39

1.0620

21.9

99.7

962.3

0.457

10.95

1.0730

24.6

117.5

955.5

0.407

12.52

1.0842

27.2

135.7

948.5

0.368

14.08

1.0955

29.7

154.2

941.3

0.337

15.64

1.1070

32.2

173.1

933.9

0.311

17.21

1.1186

34.4

192.5

926.1

0.291

18.77

1.1304

36.6

212.2

918.2

0.273

20.34

1.1424

38.6

232.4

910.0

0.259

21.90

1.1545

40.5

252.8

901.7

0.247

23.47

1.1669

42.3

273.9

893.0

0.236

25.03

1.1796

44.0

295.3

884.3

0.227

26.59

1.1926

45.6

317.1

875.5

0.219

28.16

1.2059

47.0

339.6

866.3

0.213

Note that CRC Handbook gives values
for Cs and Cw, but these count the 5H2O
as part of the solution, not the solute, which would result in a slight
error if not accounted for (this is why my values have the prime symbol).

Density of 20oC water is
actually 0.99823 [g/ml] from this
table.

If you want to use anhydrous CuSO4
(gray powder) then multiply amount of solute by 0.639 (you need less) and
use more water given by the difference.

Copyright ?2003  Raymond J. Allen