If you wanted to get to .04% hydrogen peroxide by mixing saline water with 3% hydrogen peroxide (with resulting amount being around 500 ml), how many ml of hydrogen peroxide should you mix with how many ml of hydrogen peroxide?
What about if you wanted to get to .1%?
== SolCalc - Laboratory Report ==
March 01, 2022 13:08:17
HYDROGEN PEROXIDE
w(H2O2) = 0.04 %
=======================
To prepare 500 mL of a 0.04 % solution of hydrogen peroxide we will need to dilute 6.59425 mL of 3 % H2O2 to a final volume of 500 mL with deionized (distilled) water.
SOURCE:
-------------
Name: Hydrogen peroxide
Formula: H2O2
Formula weight: 34.015 g/mol
CAS Number: 7722-84-1
NFPA: Health 3, Flammability 0, Instability 1, Special OX
CALCULATION:
-------------
The key concept is that the amount of solute in the desired solution must be equal to the amount of solute in the source solution. Remember, the concentration is the amount of a solute divided by the volume of the solution.
Before we make any calculations we have to make sure that we only use one system and one unit of measurement. DO NOT mix measurement systems and units.
Desired solution:
V0 = 500 mL * (1 L)/(1000 mL) = 0.5 L
w0 = 0.04 % = 0.04 * 1/100 = 0.0004
d0 = 0.99854 kg/L * (1 g/L)/(0.001 kg/L) = 998.54 g/L
Source solutions:
w1 = 3 % = 3 * 1/100 = 0.03
d1 = 1.00951 kg/L * (1 g/L)/(0.001 kg/L) = 1009.51 g/L
--------------------------------
First, we calculate the concentration of the desired solution
c0 = d(solution) * w(H2O2) / M(H2O2)
c0 = 998.54 g/L * 0.0004 / 34.0147 g/mol
c0 = 0.0117425 mol/L
Then, we determine the concentration of the source (stock) solution
c1 = d(H2O2) * w(H2O2) / M(H2O2)
c1 = 1009.51 g/L * 0.03 / 34.0147 g/mol
c1 = 0.890356 mol/L
Since the total amount of solute is the same before and after dilution, the volume of stock solution needed is
V1 = V0 * c0 / c1
V1 = 0.5 L * 0.0117425 mol/L / 0.890356 mol/L
V1 = 0.00659425 L
To convert the result into a desired unit we will use dimensional analysis again
V(3 % H2O2) = 0.00659425 L * (1000 mL)/(1 L) = 6.59425 mL
PROCEDURE:
-------------
First of all, fill the volumetric flask about halfway with deionized water to avoid violent reactions. NEVER add water to concentrated acid.
Choose a clean pipette of suitable size and transfer the liquid to the volumetric flask. When the whole solution has been drained, touch the tip of the pipette to the side of the volumetric flask to allow the last of the liquid to drain out. DO NOT blow out the remaining solution.
Allow the solution to reach room temperature because a volumetric flask is only accurate at the temperature at which it has been calibrated (usually 20 °C). Very carefully fill the flask to the mark on the neck of the flask, using a dropping pipette to add the last few milliliters of liquid. Mix your solution thoroughly, by inverting the flask and shaking. NEVER hold large volumetric flasks by the neck alone - provide support at the bottom.
Transfer the prepared solution to a clean, dry storage bottle and label it. NEVER store solutions in a volumetric flask.
SAFETY NOTES:
-------------
- When making chemical solutions, always use the appropriate safety equipment.
- As a general rule, always add the more concentrated solution to the less concentrated solution.
- All chemicals that you are unfamiliar with should be treated with extreme care and assumed to be highly flammable and toxic.
DISCLAIMER:
-------------
Use SolCalc at your own risk! If you don't understand the results, DON'T use them.
=======================
Everything for chemists: from the periodic system in online and PDF versions, to online calculators and free software for chemists. English-Croatian chemistry dictionary and glossary is always at hand.
www.periodni.com
== SolCalc - Laboratory Report ==
March 01, 2022 13:10:42
HYDROGEN PEROXIDE
w(H2O2) = 0.1 %
=======================
To prepare 500 mL of a 0.1 % solution of hydrogen peroxide we will need to dilute 16.4893 mL of 3 % H2O2 to a final volume of 500 mL with deionized (distilled) water.
SOURCE:
-------------
Name: Hydrogen peroxide
Formula: H2O2
Formula weight: 34.015 g/mol
CAS Number: 7722-84-1
NFPA: Health 3, Flammability 0, Instability 1, Special OX
CALCULATION:
-------------
The key concept is that the amount of solute in the desired solution must be equal to the amount of solute in the source solution. Remember, the concentration is the amount of a solute divided by the volume of the solution.
Before we make any calculations we have to make sure that we only use one system and one unit of measurement. DO NOT mix measurement systems and units.
Desired solution:
V0 = 500 mL * (1 L)/(1000 mL) = 0.5 L
w0 = 0.1 % = 0.1 * 1/100 = 0.001
d0 = 0.998765 kg/L * (1 g/L)/(0.001 kg/L) = 998.765 g/L
Source solutions:
w1 = 3 % = 3 * 1/100 = 0.03
d1 = 1.00951 kg/L * (1 g/L)/(0.001 kg/L) = 1009.51 g/L
--------------------------------
First, we calculate the concentration of the desired solution
c0 = d(solution) * w(H2O2) / M(H2O2)
c0 = 998.765 g/L * 0.001 / 34.0147 g/mol
c0 = 0.0293628 mol/L
Then, we determine the concentration of the source (stock) solution
c1 = d(H2O2) * w(H2O2) / M(H2O2)
c1 = 1009.51 g/L * 0.03 / 34.0147 g/mol
c1 = 0.890356 mol/L
Since the total amount of solute is the same before and after dilution, the volume of stock solution needed is
V1 = V0 * c0 / c1
V1 = 0.5 L * 0.0293628 mol/L / 0.890356 mol/L
V1 = 0.0164893 L
To convert the result into a desired unit we will use dimensional analysis again
V(3 % H2O2) = 0.0164893 L * (1000 mL)/(1 L) = 16.4893 mL
PROCEDURE:
-------------
First of all, fill the volumetric flask about halfway with deionized water to avoid violent reactions. NEVER add water to concentrated acid.
Choose a clean pipette of suitable size and transfer the liquid to the volumetric flask. When the whole solution has been drained, touch the tip of the pipette to the side of the volumetric flask to allow the last of the liquid to drain out. DO NOT blow out the remaining solution.
Allow the solution to reach room temperature because a volumetric flask is only accurate at the temperature at which it has been calibrated (usually 20 °C). Very carefully fill the flask to the mark on the neck of the flask, using a dropping pipette to add the last few milliliters of liquid. Mix your solution thoroughly, by inverting the flask and shaking. NEVER hold large volumetric flasks by the neck alone - provide support at the bottom.
Transfer the prepared solution to a clean, dry storage bottle and label it. NEVER store solutions in a volumetric flask.
SAFETY NOTES:
-------------
- When making chemical solutions, always use the appropriate safety equipment.
- As a general rule, always add the more concentrated solution to the less concentrated solution.
- All chemicals that you are unfamiliar with should be treated with extreme care and assumed to be highly flammable and toxic.
DISCLAIMER:
-------------
Use SolCalc at your own risk! If you don't understand the results, DON'T use them.
=======================
Everything for chemists: from the periodic system in online and PDF versions, to online calculators and free software for chemists. English-Croatian chemistry dictionary and glossary is always at hand.
www.periodni.com
