Example Data Table
| Sample mass |
Purity |
Hydrate |
Molar mass |
Approximate moles |
| 10 g |
100% |
CuCl2·2H2O |
170.48 g/mol |
0.05866 mol |
| 5 g |
98% |
CuCl2·2H2O |
170.48 g/mol |
0.02874 mol |
| 250 mg |
99% |
CuCl2·2H2O |
170.48 g/mol |
0.001452 mol |
Formula Used
Molar mass: Cu + 2Cl + 2H2O
CuCl2·2H2O molar mass: 63.546 + 2(35.45) + 2(18.015) = 170.476 g/mol
Pure mass: entered mass × purity ÷ 100
Moles: pure mass in grams ÷ molar mass
Molarity: moles ÷ solution volume in liters
Formula units: moles × 6.02214076 × 10²³
How to Use This Calculator
- Enter the measured mass of copper II chloride dihydrate.
- Select the correct mass unit.
- Enter purity from the bottle label or certificate.
- Keep hydration waters as 2 for CuCl2·2H2O.
- Add solution volume when molarity is required.
- Enter target moles to estimate needed mass.
- Press the calculate button.
- Download the result as CSV or PDF.
About Copper II Chloride Dihydrate Mole Calculations
What the Calculator Does
Copper II chloride dihydrate is written as CuCl2·2H2O. The dot shows attached water.
This water is part of the crystal formula. It must be included in the molar mass.
A common mistake is using only anhydrous CuCl2. That gives too many moles.
This calculator avoids that error. It uses the hydrate value entered in the form.
Why Purity Matters
Laboratory chemicals are rarely perfect. A bottle may show 97 percent, 98 percent, or 99 percent purity.
The usable mass is lower than the weighed mass. The calculator corrects this automatically.
It multiplies the entered mass by purity. Then it divides by molar mass.
This gives a more realistic mole value for reactions.
Useful Lab Outputs
The result includes several chemistry values. It shows moles of the hydrate compound.
It also shows copper ion moles and chloride ion moles. One formula unit gives one copper ion.
It gives two chloride ions. The calculator also estimates hydrate water moles.
These values help with stoichiometry, dilution work, and ionic concentration planning.
Solution Planning
A volume field is included for molarity. Enter the final solution volume after dilution.
The calculator converts milliliters and cubic centimeters into liters. Then it divides moles by liters.
This gives molarity in mol per liter. You can also enter target moles.
The calculator returns the mass needed for that target. Purity is included in that reverse calculation.
Good Measurement Practice
Always use a clean balance. Record the unit carefully. Check the hydrate name before weighing.
Copper II chloride dihydrate and anhydrous copper II chloride are not equal by mass.
Store the compound properly. Hydrates can change if exposed to air.
For formal work, compare results with your lab manual. Use proper safety methods.
FAQs
What is copper II chloride dihydrate?
It is CuCl2·2H2O. Each formula unit contains one copper atom, two chloride atoms, and two water molecules.
What molar mass is used?
The default molar mass is about 170.476 g/mol for CuCl2·2H2O. The calculator can adjust it if hydration waters change.
Why is water included in molar mass?
The water is part of the crystal hydrate formula. Ignoring it makes the molar mass too low and the mole result too high.
How do I calculate moles manually?
Convert mass to grams. Correct for purity. Divide pure mass by 170.476 g/mol for copper II chloride dihydrate.
Can I use milligrams?
Yes. Select milligrams in the mass unit field. The calculator converts milligrams to grams before calculating moles.
What does purity percent mean?
Purity percent shows how much of the weighed sample is actual compound. A 98 percent sample has 0.98 grams of compound per gram weighed.
How is molarity calculated?
Molarity equals moles divided by solution volume in liters. Enter the final prepared solution volume for best results.
Can this calculate required mass?
Yes. Enter target moles. The calculator estimates the required sample mass and corrects that value for purity.