Dilution is a process in science and household applications that involves reducing the concentration of a substance by mixing it with a fluid, known as a diluent or solvent. This process works by maintaining the amount of the original substance, the solute, while increasing the total volume of the mixture. Dilutions are expressed as ratios that describe the relationship between the concentrated substance and the final volume of the entire solution. Understanding these ratios dictates how much the original concentration has been weakened to achieve a desired strength.
The Meaning of the 1:10 Ratio
The 1:10 ratio, when used in the context of dilution, signifies a ten-fold reduction in concentration, often called a 10-fold dilution. This means the final solution is one-tenth (1/10) the strength of the starting material. The ratio is interpreted as one part of the concentrated substance (solute) being contained within ten total parts of the final solution. For this to occur, one part of the solute must be combined with nine parts of the diluent.
The distinction between the solute and the final volume is important for accurate preparation. A common point of confusion arises when people interpret the ratio as 1 part solute to 10 parts diluent, which would result in 11 total parts and a less concentrated final solution of 1/11th strength. In standardized contexts, a 1:10 dilution ensures the concentration is exactly 10% of the original, achieved by making the final volume ten times the initial volume of the solute.
Step-by-Step Calculation and Preparation
To prepare a 1:10 dilution, the goal is to mix the concentrated substance and the diluent so that the initial volume is precisely one-tenth of the final volume. This calculation relies on the arithmetic of parts: 1 part solute plus 9 parts diluent equals 10 total parts. The amount of solute needed is determined by dividing the total desired final volume by 10.
For example, if 100 milliliters (mL) of the final 1:10 solution is required, 10 mL of the concentrated substance is needed (100 mL divided by 10). The remaining volume is the diluent, so 10 mL of solute is added to 90 mL of diluent (100 mL – 10 mL) to make the total 100 mL. For household quantities, one-tenth of a cup of concentrate is combined with nine-tenths of a cup of diluent. The same principle applies to any unit of volume.
Common Practical Applications
The 1:10 dilution ratio is widely used across various fields. In microbiology, this dilution factor is fundamental to a technique called serial dilution, which systematically reduces the concentration of bacteria or other microorganisms in a sample. This allows researchers to achieve a manageable number of cells for accurate counting and analysis.
In household and medical settings, a 1:10 dilution is frequently the recommended ratio for preparing disinfectant solutions, such as those using household bleach. This specific ratio ensures the active ingredient is sufficiently reduced for safety while maintaining effectiveness. Furthermore, the 1:10 dilution is often used in chemistry and biochemistry to create standard curves for quantitative analysis.