Pcal Density

• What are the three main objectives of the study material on density, specific gravity, and specific volume?


  To solve problems, demonstrate specific gravity determination, and compute weights and volumes.
• How is density usually expressed?


  Density is usually expressed in g/mL.
• What is the formula for calculating specific gravity?

  Specific gravity is calculated as the weight of the substance divided by the weight of an equal volume of water.
• What is the standard temperature for measuring specific gravity?


  The standard temperature is 25 degrees Celsius.
• What is the specific gravity of water at 25 degrees Celsius?


  The specific gravity of water at 25 degrees Celsius is 1.
• What does a specific gravity less than 1 indicate about a substance?


  A specific gravity less than 1 indicates that the substance is lighter than water.
• What are the core concepts related to density, specific gravity, and specific volume?


  • Density: Measure of mass in a given volume.
  • Specific Gravity: Ratio of a substance's density to the density of water.
  • Mass: Amount of matter in an object.
  • Volume: Space an object occupies.
• What are some related terms in the context of density and specific gravity?

  • Fluid: Substance that can flow.
  • Weight: Force due to gravity on an object.
  • Concentration: Amount of substance in a volume of solution.
  • Pharmaceutical Calculations: Ensuring accurate dosages and drug preparation.
• What are practical applications of understanding density and specific gravity?


  • Dosage Calculations: Correct medication amounts.
  • Compounding: Mixing ingredients for medications.
  • Manufacturing: Ensuring quality and consistency of products.
• What is the first step in using a pycnometer to determine specific gravity?


  The first step is to weigh the empty pycnometer.
• How is the weight of water calculated when using a pycnometer?


  The weight of water is calculated by subtracting the weight of the empty pycnometer from the weight of the filled pycnometer.
• What does Archimedes' Principle state about buoyant force?


  It states that the buoyant force is equal to the weight of the displaced fluid.
• What are the steps in determining specific gravity using a pycnometer?


  1. Weigh the empty pycnometer.
  2. Fill with water and weigh again.
  3. Calculate the weight of water.
  4. Fill with another liquid and weigh.
  5. Determine specific gravity based on the weights.
• What is the first step in the specific gravity determination using the displacement method?


  Weigh the glass plummet in air.
• How do you calculate specific gravity using the displacement method?

  Specific gravity is calculated as the weight of displaced glycerin divided by the weight of displaced water.
• If 14 mL of lemon oil weighs 350 mg, what is its density?

  $\text{Density} =$$\frac{\text{mass}}{\text{volume}} =$$\frac{350 \text{ mg}}{14 \text{ mL}} =$$25 \text{ mg/mL}$
• If 10 mL of sulfuric acid weighs 18 g, what is its density?


  $\text{Density} =$$\frac{18 \text{ g}}{10 \text{ mL}} =$$1.8 \text{ g/mL}$
• If 0.2 mL of a liquid has a density of 1.8 g/mL, what is the liquid’s weight in mg?


  $\text{Weight} =$$\text{Density} \times \text{Volume} =$$1.8 \text{ g/mL} \times 0.2 \text{ mL} =$$0.36 \text{ g} =$$360 \text{ mg}$
• What is the volume (in mL) of a solution that weighs 250 g and has a specific gravity of 0.68?


  $\text{Volume} =$$\frac{\text{Weight}}{\text{SG}} =$$\frac{250 \text{ g}}{0.68} \approx 367.65 \text{ mL}$
• How do you calculate the specific gravity of oil if a glass plummet weighs 12.64 g in air, 8.57 g in water, and 9.12 g in oil?


  $\text{SG} =$$\frac{\text{Weight of displaced glycerin}}{\text{Weight of displaced water}} =$$\frac{12.64 - 9.12}{12.64 - 8.57} =$$\frac{3.52}{4.07} \approx 0.86$
• If 25 g of glycerin measures 20 mL, what is the specific volume of glycerin?


  $\text{Specific Volume} =$$\frac{\text{Volume}}{\text{Weight}} =$$\frac{20 \text{ mL}}{25 \text{ g}} =$$0.8 \text{ mL/g}$