Factor-label method

Definition

The factor-label method, also known as dimensional analysis, is a technique used to convert units by multiplying by conversion factors. It ensures that units cancel appropriately to yield the desired unit of measurement.

5 Must Know Facts For Your Next Test

1. The factor-label method relies on the principle that multiplying by a fraction equivalent to one does not change the value.
2. Conversion factors are derived from equivalence statements between different units (e.g., 1 inch = 2.54 cm).
3. Units should be treated algebraically, meaning they can cancel out like numerical values during multiplication and division.
4. This method is essential for solving problems involving multiple unit conversions in chemistry, such as converting grams to moles or liters to milliliters.
5. Accuracy in setting up conversion factors and ensuring correct unit cancellation is crucial for obtaining accurate results.

Review Questions

• What principle underlies the factor-label method that allows it to convert between units without changing the value?
• How do you derive a conversion factor from an equivalence statement?
• Why is it important to treat units algebraically when using the factor-label method?

Related terms

Conversion Factor: A ratio derived from the equality between two different units that can be used to convert from one unit to another.

Dimensional Analysis:

Another term for the factor-label method; a mathematical technique used to ensure that equations and calculations involving physical quantities are dimensionally consistent.

Equivalence Statement: A statement that expresses the equality between two different units (e.g., $1 \text{ inch} = 2.54 \text{ cm}$), allowing for conversion between those units.