Summary of Writing Conversion Factors in Chemistry

Writing Conversion Factors

  • Conversion factors can express relationships between units (e.g., 1 h = 60 min).

  • Any equality can be represented by two conversion factors: 60 min/1 h and 1 h/60 min.

Importance of Significant Figures

  • Exact numbers (like those from definitions) do not affect significant figures in calculations.

  • Measured values (derived from instruments) count towards significant figures.

Common Relationships

  • Metric to U.S. examples include:

    • 1 kg = 2.20 lb

    • 1 g = 1000 mg.

Dosage Problems

  • Dosages can be represented with conversion factors (e.g., 1 capsule of Keflex = 250 mg).

Percent as a Conversion Factor

  • A percent relationship indicates parts per 100 (e.g., 18% body fat means 18 g of fat per 100 g of body).

Conversion Factor Applications

  • Tools like dimensional analysis use conversion factors to convert units accurately.

  • One must determine the relationship between given and needed units.

Density Usage

  • Density connects mass and volume, allowing conversion between them: density=massvolumedensity = \frac{mass}{volume}.