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What is the specific gravity of the oil if a plummet weighs 12.64 g in air, 9.12 g in oil, and 8.57 g in water?
What is the specific gravity of the oil if a plummet weighs 12.64 g in air, 9.12 g in oil, and 8.57 g in water?
How much would 50 mL of a liquid with a specific gravity of 1.2 weigh?
How much would 50 mL of a liquid with a specific gravity of 1.2 weigh?
If 3620 mL of alcohol has a specific gravity of 0.820, what is its weight in grams?
If 3620 mL of alcohol has a specific gravity of 0.820, what is its weight in grams?
What formula would be used to calculate grams given milliliters and specific gravity?
What formula would be used to calculate grams given milliliters and specific gravity?
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What is the volume of 492 g of nitric acid with a specific gravity of 1.40?
What is the volume of 492 g of nitric acid with a specific gravity of 1.40?
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Which of the following best describes a practical application of specific gravity in pharmaceuticals?
Which of the following best describes a practical application of specific gravity in pharmaceuticals?
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What is the specific gravity of water considered to be?
What is the specific gravity of water considered to be?
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Why is specific gravity important in urinalysis?
Why is specific gravity important in urinalysis?
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If a liquid has a specific gravity less than 1, how does it compare to water?
If a liquid has a specific gravity less than 1, how does it compare to water?
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In calculating specific gravity, what does the weight of displaced liquid represent?
In calculating specific gravity, what does the weight of displaced liquid represent?
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What is the formula used to calculate density?
What is the formula used to calculate density?
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What unit is specific gravity measured in?
What unit is specific gravity measured in?
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If a substance has a specific gravity of 0.8, what can be inferred about its density relative to water?
If a substance has a specific gravity of 0.8, what can be inferred about its density relative to water?
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Which of the following is considered the standard substance for specific gravity calculations of liquids and solids?
Which of the following is considered the standard substance for specific gravity calculations of liquids and solids?
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At what temperature is specific gravity typically standardized for most substances, according to the USP?
At what temperature is specific gravity typically standardized for most substances, according to the USP?
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Which of the following measurements would give a specific gravity of 1 for a substance?
Which of the following measurements would give a specific gravity of 1 for a substance?
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When comparing a liquid's density to water, what does a density of 1 g/mL imply?
When comparing a liquid's density to water, what does a density of 1 g/mL imply?
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Which of the following substances is used as the standard for calculating the specific gravity of gases?
Which of the following substances is used as the standard for calculating the specific gravity of gases?
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What is the normal specific gravity range of urine in adults with normal fluid intake?
What is the normal specific gravity range of urine in adults with normal fluid intake?
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Which condition is indicated by a higher-than-normal specific gravity of urine?
Which condition is indicated by a higher-than-normal specific gravity of urine?
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What effect does age generally have on the specific gravity of urine?
What effect does age generally have on the specific gravity of urine?
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Which of the following indicates dilute urine?
Which of the following indicates dilute urine?
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What is the significance of urine specific gravity in clinical settings?
What is the significance of urine specific gravity in clinical settings?
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In newborns, what is the typical range of urine specific gravity?
In newborns, what is the typical range of urine specific gravity?
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Which method is commonly used to determine urine specific gravity in modern clinical laboratories?
Which method is commonly used to determine urine specific gravity in modern clinical laboratories?
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Which of the following factors may lead to a low specific gravity of urine?
Which of the following factors may lead to a low specific gravity of urine?
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What might a specific gravity of urine above 1.025 indicate?
What might a specific gravity of urine above 1.025 indicate?
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Which of these conditions could NOT result in low specific gravity urine?
Which of these conditions could NOT result in low specific gravity urine?
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What is the specific gravity of a liquid that weighs 601 g and displaces the weight of 473 g of water?
What is the specific gravity of a liquid that weighs 601 g and displaces the weight of 473 g of water?
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Why is specific gravity considered a dimensionless quantity?
Why is specific gravity considered a dimensionless quantity?
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What measurements are necessary to calculate the specific gravity using a pycnometer?
What measurements are necessary to calculate the specific gravity using a pycnometer?
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If a substance has a specific gravity of 0.78, what can be inferred about its density compared to water?
If a substance has a specific gravity of 0.78, what can be inferred about its density compared to water?
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What principle underlies the calculation of specific gravity using the displacement method?
What principle underlies the calculation of specific gravity using the displacement method?
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What is the equivalent weight of 54.96 mL of water in grams?
What is the equivalent weight of 54.96 mL of water in grams?
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Which method is specifically mentioned for determining specific gravity in a laboratory setting?
Which method is specifically mentioned for determining specific gravity in a laboratory setting?
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How is the density of a substance expressed compared to the specific gravity?
How is the density of a substance expressed compared to the specific gravity?
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What is the specific gravity of water when measured in any conditions?
What is the specific gravity of water when measured in any conditions?
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Which of the following is true about the density of substances at different conditions?
Which of the following is true about the density of substances at different conditions?
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Study Notes
Density and Specific Gravity
- Density is mass per unit volume at a constant temperature and pressure.
- Density is measured in grams per cubic centimeter (g/cc) or grams per milliliter (g/mL) in the CGS system.
- In SI units, density can be expressed as kilograms per cubic meter.
- Density is calculated by dividing mass by volume.
- Example: If 10 mL of sulfuric acid weighs 18 grams, its density is 1.8 g/mL.
Specific Gravity
- Specific gravity (sp gr) is a ratio of the weight of a substance to the weight of an equal volume of a standard substance at the same temperature.
- For liquids and solids, water is the standard.
- For gases, hydrogen is the standard.
- Specific gravity is a dimensionless quantity.
- Specific gravity is calculated by dividing the weight of a substance by the weight of an equal volume of water.
- Example: If 10 mL of sulfuric acid weighs 18 g, and 10 mL of water weighs 10 g, the specific gravity of the acid is 1.8.
Density vs Specific Gravity
- Density is a concrete number, specific gravity an abstract number.
- Density varies with the unit of measurement.
- Specific gravity is constant under controlled conditions.
- Density of water can be expressed as 1 g/mL, 1000 g/L, or 62.5 lb/cu ft.
- Specific gravity of water is always 1.
Calculating Specific Gravity (Known Weight and Volume Methods)
- Specific gravity = weight of substance / weight of equal volume of water
- Example 1: If 54.96 mL of oil weighs 52.78 g, its specific gravity is 0.9603.
- Example 2: If a pint of a liquid weighs 601 g, and a pint of water weighs 473 g, its specific gravity is 1.27.
Pycnometer or Specific Gravity Bottle
- A pycnometer is a special glass bottle for determining specific gravity.
- It has a volume ranging from 1 to 50 mL.
- A pycnometer is weighed empty, then filled with water, then filled with the substance and weighed again.
- Example: A 50 mL pycnometer weighs 120 g empty, 171 g when filled with water, and 160 g when filled with an unknown liquid. The specific gravity of the liquid is 0.78
Displacement or Plummet Method
- Based on Archimedes' principle, a body immersed in a fluid displaces an equal volume of fluid.
- A plummet (a weighted object) is weighed in air, water and a liquid of unknown density.
- The difference in weight corresponds to the weights of displaced liquid.
- Example: A glass plummet weighs 12.64 g in air, 8.57 g in water, and 9.12 g in oil. The specific gravity of the oil is 0.865.
Using Specific Gravity in Calculations
- Specific gravity is a factor that helps determine how much heavier or lighter a substance is compared to water (water's specific gravity is 1).
- If a liquid's specific gravity is 1.2, it weighs 1.2 times as much as an equal volume of water.
- Example: 50 mL of a liquid with a specific gravity of 1.2 would weigh 60 grams (50 mL x 1.2 = 60 g)
Calculating Weight, Knowing Volume and Specific Gravity
- Grams = Milliliters x Specific gravity
- Example: What is the weight (in grams) of 3620 mL of alcohol with a specific gravity of 0.820? The answer is 2968 grams
Calculating Volume, Knowing Weight and Specific Gravity
- Milliliters = Grams / Specific gravity
- Example: What is the volume (in milliliters) of 492 g of nitric acid with a specific gravity of 1.40? The answer is 351 mL.
Pharmaceutical Applications
- Specific gravity converts weight to volume and vice-versa.
- It calculates equivalent strength based on weight or volume.
- Pharmacists use it in automated equipment (TPN admixtures).
- It's used to determine weights of components (e.g., dextrose, amino acids, water) in large volume liquid mixtures.
Clinical Application (Urinalysis)
- Specific gravity is crucial in urinalysis.
- Normal adult urine ranges from 1.010 to 1.025.
- Specific gravity decreases with age.
- Newborn urine ranges from 1.001 to 1.020.
- High specific gravity indicates concentrated urine, potential excess waste products, electrolytes, glucose or protein.
- Low specific gravity suggests dilute urine, possibly from diabetes insipidus, renal disease, increased fluid intake, IV hydration, etc.
- Modern labs use refractive index methods to determine specific gravity in comprehensive urinalysis.
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Description
Test your understanding of density and specific gravity concepts. This quiz covers definitions, calculations, and examples relevant to both topics. Perfect for students learning about the physical properties of substances.
