Quick Reference Guide For Dilution Formulas And Conversion Factors

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Understanding dilution formulas and conversion factors is essential for students and professionals working in laboratories, pharmacies, and scientific research. This quick reference guide provides key formulas and conversion factors to facilitate accurate calculations and conversions in various contexts.

Basic Dilution Formulas

The most common dilution formula involves the relationship between the concentrations and volumes of the stock and diluted solutions:

C1 × V1 = C2 × V2

Where:

  • C1 = initial concentration (stock solution)
  • V1 = volume of stock solution used
  • C2 = final concentration after dilution
  • V2 = total volume of the diluted solution

Calculating Dilution Factors

The dilution factor (DF) indicates how much a solution has been diluted:

DF = Vfinal / Vinitial

Or, when considering concentrations:

DF = Cinitial / Cfinal

Common Conversion Factors

Conversion factors are used to switch between units. Here are some essential ones:

  • 1 milliliter (mL) = 0.001 liters (L)
  • 1 liter (L) = 1000 milliliters (mL)
  • 1 gram (g) = 1000 milligrams (mg)
  • 1 kilogram (kg) = 1000 grams (g)
  • 1 inch = 2.54 centimeters (cm)
  • 1 foot = 12 inches
  • 1 mile = 1,609.34 meters (m)

Converting Concentrations

Concentrations are often expressed in different units. Here are common conversions:

  • 1% solution = 1 gram per 100 mL
  • 1 mg/mL = 1,000 mg per 1,000 mL = 1 g/L
  • To convert from mg/mL to g/L, divide by 1000

Practical Examples

Example 1: You have 10 mL of a 5% solution and want to dilute it to 100 mL. What is the final concentration?

Using the dilution formula:

C2 = (C1 × V1) / V2

Substituting values:

C2 = (5% × 10 mL) / 100 mL = 0.5%

Example 2: Convert 250 mg/mL to g/L.

Divide by 1000:

250 mg/mL ÷ 1000 = 0.25 g/mL = 250 g/L