What is the weight of 1000 ml of serum protein whose specific gravity is 1.27?

Specific gravity is the ratio of the density of a substance to the density of a reference substance, which for liquids is typically water (density ≈ 1 g/mL). Therefore, the density of the serum protein is numerically equal to its specific gravity, i.e., 1.27 g/mL. The weight (mass) of a substance can be calculated by multiplying its volume by its density. Weight = Volume × Density Weight = 1000 mL × 1.27 g/mL Weight = 1270 g

B. 127mg: This represents a significant miscalculation in both magnitude and units; it would be the weight of approximately 0.1 mL.
C. 12.7mg: This is incorrect in both magnitude and units, representing a calculation error of several orders of magnitude.
D. 12.7gm: This is a decimal placement error; it would be the correct weight for a volume of 10 mL, not 1000 mL.
E. 1.27gm: This is also a decimal placement error; it would be the correct weight for a volume of 1 mL.

1. Ansel, H. C., & Stoklosa, M. J. (2016). Pharmaceutical Calculations (15th ed.). Wolters Kluwer. In Chapter 5, "Density, Specific Gravity, and Specific Volume," the text explains that the weight of a substance can be found by multiplying its volume by its specific gravity (p. 63, Example Calculation).

2. United States Pharmacopeia and National Formulary (USP 43-NF 38). (2020). General Chapter Specific Gravity. This chapter defines specific gravity and its relationship to density, confirming that for a substance with a specific gravity of X, its density is X g/mL when referenced to water.

3. University of Toledo, College of Pharmacy and Pharmaceutical Sciences. Pharmaceutics I (PHPR 2050) Course Packet. The section on "Pharmaceutical Calculations" covers the relationship between weight, volume, and specific gravity, defining the formula: Weight (g) = Volume (mL) × Specific Gravity (p. 12).