Calculate %m/v, Mass-Volume Percent + 2 Examples

chemistNATE
18 Oct 202003:29
EducationalLearning
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TLDRThe video explains the concept of mass volume percent, detailing how to measure the grams of solute dissolved in a certain volume of solution, specifically in milliliters. It demonstrates the calculation using an example where 12.4 grams of solute is dissolved to make 125 milliliters of solution, resulting in a 9.92% mass volume percent. The process includes converting units and ensuring significant figures are accurate. Additionally, the video covers how to determine the mass of sodium fluoride in toothpaste with a 0.3% mass volume concentration, emphasizing the importance of units and significant figures in the calculations.

Takeaways
  • 📏 Mass volume percent is a measure of the amount of solute dissolved in a certain volume of solution, typically expressed in grams per 100 milliliters.
  • 📉 The volume of the solution must always be in milliliters, and the mass of the solute must be in grams.
  • 🔢 To calculate mass volume percent, divide the mass of the solute by the total volume of the solution and multiply by 100.
  • 📉 For the example given, dissolving 12.4 grams of a substance in 125 milliliters of solution results in a mass volume percent of 9.92%.
  • 🎼 The calculation involves moving the decimal place two places to the right to convert from a decimal to a percentage.
  • 📦 When calculating mass volume percent, it's important to maintain the correct number of significant figures, as demonstrated with the example of toothpaste containing 0.3% sodium fluoride.
  • 🧴 To find the actual mass of sodium fluoride in a 140 milliliter tube of toothpaste with 0.3% mass by volume concentration, multiply 140 by 0.3 and divide by 100, resulting in 0.42 grams.
  • ⚖️ The final answer for the mass of sodium fluoride should consider the significant figures, which in this case would be rounded to 0.4 grams if following significant figure rules.
  • 📝 The formula for mass volume percent is grams of solute divided by the volume of solution (in milliliters) times 100, expressed as a percentage.
  • 🔍 Understanding mass volume percent is crucial for accurately measuring and preparing solutions in various applications, including scientific experiments and everyday products like toothpaste.
Q & A

  • What is mass volume percent and how is it measured?

    -Mass volume percent is a measure of the concentration of a solute in a solution. It is calculated by the number of grams of solute dissolved in 100 milliliters of the solution and is expressed as a percentage.

  • What units are required for mass and volume when calculating mass volume percent?

    -The mass must be in grams and the volume must be in milliliters when calculating the mass volume percent.

  • How do you calculate the mass volume percent if 12.4 grams of a solute are dissolved to make 125 milliliters of solution?

    -To calculate the mass volume percent, divide the mass of the solute (12.4 grams) by the total volume of the solution (125 milliliters), then multiply by 100 to convert it to a percentage, which in this case would be 9.92%.

  • What does the term 'solution' refer to in the context of mass volume percent?

    -In the context of mass volume percent, 'solution' refers to the combination of solute and solvent.

  • How do you convert a mass volume percent to a decimal?

    -To convert a mass volume percent to a decimal, divide the percentage by 100. For example, a 9.92% mass volume percent would be 0.0992 as a decimal.

  • What is the significance of significant figures in the calculation of mass volume percent?

    -Significant figures are important in scientific calculations to indicate the precision of the measurement. In the example given, both the mass and volume had three significant figures, so the final answer should also have three significant figures.

  • What is the mass volume percent of sodium fluoride in a toothpaste that contains 0.3% mass by volume?

    -The mass volume percent of sodium fluoride in the toothpaste is 0.3%.

  • How much sodium fluoride is in a 140 milliliter tube of toothpaste with a 0.3% mass volume concentration?

    -To find the mass of sodium fluoride, multiply the volume of toothpaste (140 milliliters) by the mass volume percent (0.3%) and then divide by 100, which results in 0.42 grams of sodium fluoride.

  • Why is it important to consider significant figures when reporting the mass of sodium fluoride in the toothpaste example?

    -Considering significant figures is important to maintain the accuracy and precision of the measurement. In the example, the final answer should reflect the precision of the original measurements, which is why it is rounded to two significant figures.

  • What is the general formula for calculating mass volume percent?

    -The general formula for calculating mass volume percent is (mass of solute in grams / volume of solution in milliliters) * 100%.

Outlines
00:00
📊 Understanding Mass Volume Percent

Mass volume percent measures how many grams of solute are dissolved in a certain volume of solution, expressed in milliliters. It is given as a percentage, indicating grams of solute per 100 milliliters of solution. The mass must be in grams and the volume in milliliters. For example, to find the mass volume percent of a solution with 12.4 grams of solute in 125 milliliters of solution, divide 12.4 by 125 and multiply by 100, resulting in 9.92%.

📐 Calculating Sodium Fluoride in Toothpaste

To determine the amount of sodium fluoride in a tube of toothpaste with 0.3% mass by volume in a 140 milliliter tube, the given percent must be used. Here, 0.3% is converted to a decimal (0.003), and by solving for mass using the given volume, the mass of sodium fluoride is found to be 0.42 grams. This calculation considers significant figures, resulting in a final value of 0.4 grams due to the precision of the given numbers.

📝 Summary of Mass Volume Percent Calculation

Mass volume percent quantifies grams of solute per 100 milliliters of solution. The calculation involves ensuring mass is in grams and volume is in milliliters, multiplying by 100 to express as a percentage. Key points include the necessity of correct units and the impact of significant figures on the final result. The explanation concludes with an encouragement for the application of these concepts.

Mindmap
Keywords
💡Mass Volume Percent
Mass volume percent is a concentration measure that indicates the amount of solute present in a given volume of solution, typically expressed as grams per 100 milliliters. It is a fundamental concept in chemistry and related sciences, used to standardize solutions. In the video, the concept is used to calculate the concentration of a solution where 12.4 grams of solute are dissolved in 125 milliliters of solution, resulting in a 9.92% mass volume percent.
💡Solute
A solute is the substance that is dissolved in a solvent to form a solution. It is one of the two main components of a solution, the other being the solvent. In the context of the video, the solute is an unspecified substance that, when dissolved, helps determine the mass volume percent of the solution. The example given is dissolving 12.4 grams of a solute in 125 milliliters of solution.
💡Solvent
A solvent is a substance, usually a liquid, that has the ability to dissolve other substances (solutes) to form a solution. While the solvent is not explicitly defined in the script, it is implied as the medium in which the solute is dissolved. The video's theme revolves around calculating the mass volume percent, which inherently involves understanding the relationship between solute and solvent.
💡Concentration
Concentration in chemistry refers to the amount of a particular substance in a given volume of a mixture or solution. It is a vital concept for understanding how much of a substance is present in a solution. The video script discusses mass volume percent as a form of concentration, specifically how many grams of solute are dissolved in 100 milliliters of solution.
💡Milliliters
Milliliters (mL) is a unit of volume in the metric system, commonly used to measure the volume of liquids. In the script, milliliters are the specified unit for the volume of the solution when calculating the mass volume percent. The example provided uses 125 milliliters of solution to determine the concentration of the solute.
💡Significant Figures
Significant figures are the digits in a number that carry meaningful information about its precision. They are important in scientific calculations to ensure accuracy and consistency. The video script mentions significant figures when discussing the result of the mass volume percent calculation, emphasizing that the answer should reflect the precision of the original measurements.
💡Percent
Percent means 'per hundred' and is used to express a ratio or fraction of 100. In the context of the video, percent is used to express the mass volume percent, which is the ratio of grams of solute to 100 milliliters of solution. The script explains that the mass volume percent is obtained by multiplying the fraction of grams of solute to milliliters of solution by 100.
💡Toothpaste
Toothpaste is a paste or gel used with a toothbrush to clean and maintain the health of teeth. In the script, toothpaste serves as a real-world application of the concept of mass volume percent. It mentions that a certain brand of toothpaste contains 0.3% mass by volume of sodium fluoride, illustrating how this chemical property is relevant in everyday products.
💡Sodium Fluoride
Sodium fluoride is a chemical compound used in various applications, including toothpaste, where it helps prevent tooth decay. In the video script, sodium fluoride is used as an example to demonstrate how to calculate the mass of a solute (in this case, 0.3% by volume) in a given volume of a solution (140 milliliters of toothpaste), resulting in 0.42 grams of sodium fluoride.
💡Calculation
Calculation refers to the process of computing or determining something, often using mathematical methods. The video script involves several calculations to determine the mass volume percent of a solution and the mass of sodium fluoride in toothpaste. These calculations are central to the video's educational purpose, teaching viewers how to apply mathematical operations to chemical concepts.
Highlights

Mass volume percent is a measure of how many grams of solute is dissolved in a certain volume of solution.

The volume in mass volume percent must always be in milliliters.

Mass volume percent is expressed as a percentage, indicating how many grams dissolve in 100 milliliters.

The mass must be in grams and the volume in milliliters for calculating mass volume percent.

To calculate mass volume percent, use the formula: (grams of solute / volume in milliliters) * 100.

Example calculation: Dissolving 12.4 grams in 125 milliliters results in a mass volume percent of 9.92%.

The unit for mass volume percent is written as percent m over v.

Significant figures in the calculation should match the number of significant figures in the original data.

In a practical example, a 140 milliliter tube of toothpaste contains 0.3% mass by volume of sodium fluoride.

To find the mass of sodium fluoride in the toothpaste, convert the percentage to a decimal and use the formula.

The mass of sodium fluoride in the toothpaste is calculated to be 0.42 grams.

When calculating, ensure the volume is in milliliters and the mass is in grams.

Multiply by 100 to convert the ratio of grams to milliliters into a percentage.

The mass volume percent calculation is crucial for understanding the concentration of solutes in solutions.

Practical applications of mass volume percent include determining the concentration of ingredients in consumer products.

Accuracy in significant figures is important for maintaining the precision of scientific calculations.

Understanding mass volume percent is essential for various scientific and industrial processes.

Transcripts

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