How to Dilute Solutions

PDF download Download Article
PDF download Download Article

Dilution is the process of making a concentrated solution less concentrated. There are a variety of reasons why one might want to perform a dilution. For example, biochemists dilute solutions from their concentrated form to create new solutions for use in their experiments. As a more casual type of dilution, bartenders often dilute hard liquor with a soft drink or juice to make a cocktail more palatable. For diluting solutions in lab experiments, the formal formula for calculating a dilution is C 1 V 1 = C 2 V 2 , where C 1 and C 2 represent the concentrations of the initial and final solutions, respectively, and V 1 and V 2 represent their volumes.

Method 1
Method 1 of 2:

Accurately Diluting Concentrates via Dilution Equation

PDF download Download Article
  1. Performing a dilution in chemistry usually means taking a small amount of a solution whose concentration you know, then adding a neutral liquid (like water) to make a new solution with a larger volume but a lower concentration. This is done very frequently in chemistry labs, as, for efficiency's sake, reagents are often stored at relatively high concentrations which are then diluted for use in experiments. Usually, in most real-world situations, you will know the concentration of your starting solution and both the concentration and volume you want in your second solution, but not the volume of the first solution you need to use to get there. [1]
    • However, in other situations (especially in schoolwork problems), you may need to find some other part of the puzzle - for instance, you may be given an initial volume and concentration, then asked to find the final concentration if you dilute the solution to a given volume. In the case of any dilution, it's helpful to take stock of known and unknown variables before beginning.
    • Let's tackle an example problem. Say that we're tasked with diluting a 5 M (molar) solution with water to make 1 liter (0.3 US gal) of a 1 mM (millimolar) solution. In this case, we know the concentration of the solution we're starting with and the target volume and concentration we want, but not how much of the initial solution we need to add water to get there.
      • Reminder: In chemistry, M is a measure of concentration called Molarity , which indicates moles of a substance per liter.
  2. In this formula, C 1 is the concentration of the starting solution, V 1 is the volume of the starting solution, C 2 is the concentration of the final solution, and V 2 is the volume of the final solution. Plugging your known values into this equation will allow you to find the unknown value with minimum difficulty. [2]
    • You may find it helpful to put a question mark in front of the variable that you are solving for.
    • Let's continue our example. We would plug our known values in as follows:
      • C 1 V 1 = C 2 V 2
      • (5 M)V 1 = (1 mM)(1 L). Our two concentrations have different units. Let's stop here and proceed to the next step.
    Advertisement
  3. Because dilutions involve changes in concentration (which can sometimes be quite large), it's not uncommon for two variables in your equation to be in different units. Though this is easily overlooked, mismatching units in your equation can cause your answer to be orders of magnitude off. Before solving, convert all values with differing concentration and/or volume units. [3]
    • In our example, we use different units for concentration M (molar) and mM (millimolar). [4] Let's convert our second measurement to M:
      • 1 mM × 1 M/1,000 mM (There are 1,000 mM per 1 M.)
      • = 0.001 M
  4. When all your units match, solve your equation. This almost always can be done with simple algebra. [5]
    • We left our example problem here: (5 M)V 1 = (1 mM)(1 L). Let's solve for V 1 with our new units.
      • (5 M)V 1 = (0.001 M)(1 L)
      • V 1 = (0.001 M)(1 L)/(5 M).
      • V 1 = 0.0002 L., or 0.2 mL.
  5. Let's say you have found your missing value, but you're unsure of how to apply this new information to a real-world dilution you need to perform. This is understandable - the language of math and science sometimes doesn't lend itself to the real world. When you know all four values in the equation C 1 V 1 = C 2 V 2 , perform your dilution as follows: [6]
    • Measure the volume V 1 of the solution with concentration C 1 . Then, add enough diluting liquid (water, etc.) to make a total volume V 2 . This new solution will have your desired concentration (C 2 ). [7]
    • In our example, for instance, we would first measure 0.2 milliliters (0.007  fl oz) of our 5 M solution. Next, we would add enough water to increase the volume of the solution to 1 L: 1 L - 0.0002 L = 0.9998 L, or 999.8 milliliters (33.8  fl oz). In other words, we would add 999.8 milliliters (33.8  fl oz) of water to our tiny sample of solution. Our new, diluted solution has a concentration of 1 mM, which is what we wanted in the first place.
    6. Advertisement
Method 2
Method 2 of 2:

Making Simple, Practical Dilutions

PDF download Download Article
  1. There are a wide variety of reasons why you might want to make a dilution at home, in the kitchen, or in another non-chemistry lab setting. For instance, the simple act of making orange juice from concentrate is a dilution. In many cases, products that need to be diluted include information about the dilution that needs to be made somewhere on the packaging. They may even have precise directions to follow. [8] Here are some things to look for when searching for information:
    • The volume of the product to use
    • The volume of the diluting liquid to use
    • The type of diluting liquid to be used (usually water)
    • Special mixing instructions
    • You probably won't see information about the precise concentrations of the liquids being used. This information is superfluous to the average consumer.
  2. For simple household dilutions, such as the ones you might make in the kitchen, you only really need to know the volume of concentrate you're using and the approximate final concentration you'd like before beginning. Dilute the concentrate with an appropriate amount of diluting liquid, which is determined relative to the initial volume of concentrate being used. [9] See below:
    • For example, if we want to dilute 1 cup of concentrated orange juice to 1/4 its initial concentration, we would add 3 cups of water to the concentrate. Our final mixture would have 1 cup of concentrate in 4 cups of total liquid - 1/4 its initial concentration.
    • Here's a more complex example: If we wanted to dilute 2/3 cup of concentrate to 1/4 its initial concentration, we would add 2 cups of water, because 2/3 cup is 1/4th of 2&2/3 cups total liquid.
    • Be sure to add your substances to a vessel that's big enough to accommodate the final volume you want - a large bowl or similar container.
  3. Adding powders (like certain drink mixes) to liquids usually doesn't need to be thought of as a "dilution." The volume change created by the addition of a small amount of powder to a liquid is usually small enough that it can be effectively ignored. In other words, when adding small amounts of powder to a liquid, just add the powder to the final volume of liquid you want and mix.
    4. Advertisement


Video

Community Q&A

Search
Add New Question
  • Question
    How can I prepare 5% of hydrochloric acid solution from concentrate HCl?
    Community Answer
    Measure out 5 ml. of HCl acid, transfer it to a 100 ml. volumetric flask, and fill the flask to the mark with deionized water.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 20 Helpful 26
  • Question
    Why should I dilute cleaning chemicals?
    Community Answer
    If they are concentrated, the fumes can be very harmful if they are breathed in, as they can damage the 'hairs' in the trachea. Furthermore, if they touch the skin, they can cause severe to mild irritation. Apart from this, they can also be harmful to the surface that you are trying to clean, especially if it is wood, or other such sensitive materials. All this is because cleaning products are usually strong alkalis.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 4 Helpful 14
  • Question
    How do I dilute a 0.9 percent solution of 500 ml to a .45 percent solution?
    Community Answer
    Provided that your solvent (a major component) is nearly pure, then you need another 500 ml. Hence you will have 0.45 percent solution since you haven't changed the solute (a minor component). This is because you increased the total solution to 1L.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 10 Helpful 28
See more answers
Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Submit
      Thanks for submitting a tip for review!

      Warnings

      • Follow any safety guidelines provided by the manufacturing company or that your company requires. This is especially important if you need to dilute an acid solution. [10]
        Thanks
        Helpful 0 Not Helpful 0
      • Working with an acid solution may require more detailed steps and safety guidelines than diluting non-acid solutions. [11]
        Thanks
        Helpful 0 Not Helpful 0
      Advertisement

      You Might Also Like

      How to
      Dilute an Acid
      How to
      Conduct the Squeaky Pop Experiment
      How to
      Make Natural Outdoor Fly Repellent with Essential Oils
      How to
      Make Copper Sulfate
      How to
      Balance Chemical Equations
      How to
      Find Valence Electrons
      How to
      Find the Number of Protons, Neutrons, and Electrons
      How to
      Measure VO2 Max
      How to
      Electroplate Household Metals
      How to
      Make an Explosion
      How to
      Find Oxidation Numbers
      How to
      Read the Periodic Table
      How to
      Store Dry Ice
      How to
      Make a Small 3D Atom Model
      Advertisement

      References

      1. ↑ https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Beginning_Chemistry_(Ball)/11%3A_Solutions/11.04%3A_Dilutions_and_Concentrations
      2. ↑ https://chem.libretexts.org/Courses/Heartland_Community_College/CHEM_120%3A_Fundamentals_of_Chemistry/07%3A_Solutions/7.19%3A__Concentrations%3A_Dilution
      3. ↑ https://www.ncbi.nlm.nih.gov/books/NBK560924/
      4. ↑ https://www.mathcentre.ac.uk/resources/uploaded/module2textbooklike.pdf
      5. ↑ https://chem.libretexts.org/Courses/Heartland_Community_College/CHEM_120%3A_Fundamentals_of_Chemistry/07%3A_Solutions/7.19%3A__Concentrations%3A_Dilution
      6. ↑ https://chem.libretexts.org/Courses/Heartland_Community_College/CHEM_120%3A_Fundamentals_of_Chemistry/07%3A_Solutions/7.19%3A__Concentrations%3A_Dilution
      7. ↑ https://www.mathcentre.ac.uk/resources/uploaded/diluting-a-solution.pdf
      8. ↑ https://www.nidirect.gov.uk/articles/chemical-safety-home
      9. ↑ https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Map%3A_Introductory_Chemistry_(Tro)/13%3A_Solutions/13.07%3A_Solution_Dilution
      1. ↑ https://www.ehs.harvard.edu/sites/default/files/lab_safety_guideline_hydrochloric_acid.pdf
      2. ↑ https://www.snc.edu/chemicalhygiene/docs/labsafety/SolutionPrep.pdf

      About This Article

      Article Summary X

      To dilute solutions, such as simple household solutions, make sure you know the volume of concentrate you’re using and the approximate final concentration you’d like to wind up with. For example, if you want to dilute 1 cup of concentrated orange juice to ¼ its initial concentration, add 3 cups of water for a total of 4 cups liquid. To learn how to accurately dilute concentrates with dilution equations, keep reading!

      Did this summary help you?
      In other languages
      Thanks to all authors for creating a page that has been read 426,434 times.

      Did this article help you?

      Advertisement