How to calculate normmality in chemistry?

Najam Academy

15 Aug 202220:58

EducationalLearning

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TLDRThis chemistry lecture introduces the concepts of dissociation, equivalent mass, and normality. It explains how acids like HCl and bases like sodium hydroxide ionize in water, producing hydrogen or hydroxide ions. The lecture then delves into calculating equivalent mass, which measures a molecule's reactive capacity, using the molar mass and the number of dissociable ions. It also covers the calculation of normality, which is the concentration of a solution based on the number of grams equivalent of solute per liter. The script provides step-by-step examples for calculating equivalent mass and normality, helping students understand these fundamental chemistry concepts.

Takeaways

🌟 The video explains the concept of equivalent mass, equivalent weight, and gram equivalent, which are used to measure the reactive capacity of a molecule.
🔍 When acids like HCl are dissolved in water, they ionize into hydrogen ions (H+), with x representing the number of ions produced per molecule, which is 1 for HCl.
🌀 Similarly, bases like sodium hydroxide (NaOH) ionize into sodium ions (Na+) and hydroxide ions (OH-), with x also being 1 for NaOH.
📚 The molar mass of a molecule, such as H2SO4, is calculated by adding the molar masses of its constituent atoms and represents the mass of one mole of the substance.
⚖️ The equivalent mass of a substance is calculated by dividing the molar mass by the number of ions (x) it produces, indicating the reactive capacity per gram of the substance.
🧪 The video demonstrates how to calculate the equivalent mass for various substances, including HCl, NaOH, Na2CO3, and H2SO4, using the formula: Equivalent mass = Molar mass / x.
📉 To find the number of grams equivalent for a given mass of a substance, divide the given mass by the equivalent mass.
📚 Normality (N) is defined as the number of gram equivalents of solute dissolved in one liter of solution, and it measures the concentration of a solution based on its reactive capacity.
🔄 The relationship between molarity (M) and normality (N) is given by N = M * x, where x is the number of ions per formula unit of the solute.
📈 The video provides step-by-step calculations for determining the normality of solutions, including converting volumes to liters, calculating equivalent masses, and using the normality formula.
📝 An advanced example is given to calculate the mass of H2SO4 in a semi-normal solution, illustrating the application of normality in solving practical chemistry problems.

Q & A

What is the basic concept of dissociation or ionization of acids and bases in water?
-Dissociation or ionization refers to the process where an acid or base breaks down into ions when added to water. For example, HCl ionizes into hydrogen ions (H+) and chloride ions (Cl-), while sodium hydroxide (NaOH) ionizes into sodium ions (Na+) and hydroxide ions (OH-).
What does 'x' represent in the context of acid and base ionization?
-In the context of acid and base ionization, 'x' represents the number of hydrogen ions (H+) or hydroxide ions (OH-) produced when one molecule of the acid or base dissociates in water.
How is molar mass different from equivalent mass?
-Molar mass refers to the mass of one mole of a substance, usually expressed in grams per mole (g/mol). Equivalent mass, on the other hand, is a measure of the reactive capacity of a molecule and is calculated by dividing the molar mass by the number of ions 'x' that the molecule can produce.
What is the molar mass of H2SO4, and how is it calculated?
-The molar mass of H2SO4 is 98 grams per mole. It is calculated by adding the molar masses of its constituent atoms: 2 hydrogen atoms (2 x 1 g/mol), 1 sulfur atom (32 g/mol), and 4 oxygen atoms (4 x 16 g/mol).
How do you calculate the equivalent mass of H2SO4?
-To calculate the equivalent mass of H2SO4, divide the molar mass (98 g/mol) by the number of hydrogen ions 'x' it can produce, which is 2. The equivalent mass is therefore 98 g/mol divided by 2, resulting in 49 g.
What is the concept of normality in chemistry?
-Normality in chemistry is a measure of the concentration of a solution, specifically the number of gram equivalents of solute dissolved in one liter of solution.
How is normality related to molarity?
-Normality (N) is related to molarity (M) by the formula N = M x x, where 'x' is the number of ions produced by the dissociation of one molecule of the solute.
What is the difference between molarity and normality?
-Molarity measures the number of moles of solute per liter of solution, while normality measures the number of gram equivalents of solute per liter of solution.
How can you calculate the normality of a solution if you know the mass of the solute and the volume of the solution?
-To calculate the normality of a solution, first determine the equivalent mass of the solute, then calculate the number of grams equivalent of solute by dividing the given mass by the equivalent mass. Finally, divide the number of grams equivalent by the volume of the solution in liters to obtain the normality.
What does it mean if a solution is described as 'binormal'?
-A 'binormal' solution has a normality of 2N, meaning that there are two gram equivalents of solute dissolved in one liter of solution.
Can you provide an example of calculating the mass of solute in a given volume of a solution with a known normality?
-Yes, for example, in a 200 ml (0.2 L) binormal (2N) H2SO4 solution, first convert the volume to liters, then use the normality to find the number of grams equivalent of solute (0.2 L x 2N = 0.4 g-equiv). Knowing the equivalent mass of H2SO4 (49 g), divide the grams equivalent by the equivalent mass to find the mass of H2SO4 present.

Outlines

00:00

🧪 Basic Concepts of Normality and Equivalent Mass

This paragraph introduces the fundamental concepts of normality and equivalent mass in chemistry. It explains the dissociation or ionization process of acids and bases in water, using HCl and sodium hydroxide as examples. The number of ions produced is represented by 'x', which is crucial for understanding equivalent mass. The paragraph also covers the calculation of molar mass and equivalent mass, using H2SO4 as an example to illustrate the concept of reactive capacity of a molecule.

05:02

📚 Calculation of Equivalent Mass and Gram Equivalent

This section delves into the calculation of equivalent mass for different substances, emphasizing the importance of knowing the molar mass and the value of 'x'. It provides step-by-step calculations for HCl, sodium hydroxide, and sodium carbonate, demonstrating how to determine the reactive capacity in grams. The paragraph also explains how to calculate the number of grams equivalent given a certain mass of a substance, using H2SO4 and sodium hydroxide as examples.

10:03

🔍 Understanding Normality and Its Calculation

The paragraph explains the concept of normality, which measures the concentration of a solution based on the number of gram equivalents of solute dissolved in one liter of solution. It contrasts normality with molarity, which is based on the number of moles. The paragraph provides a detailed example of calculating the normality of a solution by dissolving a given mass of H2SO4 in water, converting mass to grams equivalent, and then applying the normality formula.

15:04

📘 Advanced Normality Calculations and Concepts

This part of the script covers advanced concepts of normality, including the relationship between molarity and normality, and how to calculate the mass of a solute in a solution when the normality is given. It explains the meaning of 'm' in molarity and 'n' in normality, and uses the example of a 2M H3PO4 solution to illustrate the calculation. The paragraph also provides a numerical example to calculate the mass of H2SO4 in a semi-normal solution.

20:05

📚 Final Thoughts on Normality Calculations

The final paragraph wraps up the lecture on normality by summarizing the key points and reiterating the importance of understanding the concepts of molarity and normality. It emphasizes the practical application of these concepts in chemistry, particularly in the calculation of the mass of a solute in a given volume of solution, and encourages the viewers to remember the formulas and principles discussed throughout the lecture.

Mindmap

Keywords

💡Normality

Normality is a measure of concentration in a solution, defined as the number of gram equivalents of solute dissolved in one liter of solution. It is a fundamental concept in the video, as it is used to understand the reactive capacity of different substances in a solution. For example, the video explains that a one normal solution of HCl means that there is one gram of HCl that has the capacity to react in a liter of solution.

💡Equivalent Mass

Equivalent mass, also referred to as gram equivalent, is the mass of a substance that will either provide or react with one gram equivalent of hydrogen or hydroxide ions. It is central to the video's theme as it helps in understanding the reactive capacity of a molecule. The script illustrates this by explaining that the equivalent mass of H2SO4 is 49 grams, meaning out of 98 grams of H2SO4, only 49 grams have the capacity to react.

💡Molar Mass

Molar mass is the mass of one mole of a given substance, typically expressed in grams per mole. It is a key concept in the video as it is used to calculate the equivalent mass and normality. For instance, the molar mass of H2SO4 is given as 98 grams per mole, which is then used to find its equivalent mass and subsequently its normality in a solution.

💡Dissociation

Dissociation, also known as ionization, is the process by which a compound breaks down into its constituent ions when dissolved in a solvent, such as water. The video uses dissociation to explain how acids like HCl and bases like sodium hydroxide break down into their respective ions, with the number of ions represented by 'x', which is essential for calculating equivalent mass and normality.

💡Acid

An acid is a substance that donates hydrogen ions (H+) when dissolved in a solution. In the context of the video, HCl is used as an example of an acid, which dissociates into hydrogen ions and chloride ions in water. The concept of acid is integral to understanding the reactive capacity and normality calculations in the video.

💡Base

A base is a substance that donates hydroxide ions (OH-) when dissolved in a solution. Sodium hydroxide is used in the video as an example of a base, which dissociates into sodium ions and hydroxide ions in water. The concept of a base is crucial for understanding the video's discussion on the reactive capacity of substances and their normality.

💡Ion

An ion is an atom or molecule that has an unequal number of protons and electrons, resulting in a net electrical charge. The video discusses ions in the context of dissociation, where acids and bases break down into their respective ions, such as hydrogen ions from HCl and hydroxide ions from sodium hydroxide.

💡Molarity

Molarity is a measure of concentration defined as the number of moles of solute dissolved in one liter of solution. While the video primarily focuses on normality, it also touches on molarity and explains the relationship between the two, stating that normality (N) is equal to molarity (M) multiplied by the number of ions (x) a compound dissociates into.

💡Gram Equivalent

Gram equivalent is the amount of a substance that will either provide or react with one gram of hydrogen or hydroxide ions. It is synonymous with equivalent mass and is used in the video to calculate the reactive capacity of different substances in a solution, which is essential for determining normality.

💡Solute

A solute is the substance that is dissolved in a solvent to form a solution. In the video, solutes such as HCl, sodium hydroxide, and calcium hydroxide are discussed in relation to their normality and equivalent mass. Understanding the solute is important for grasping the concepts of molarity and normality.

💡Solvent

A solvent is a substance, usually a liquid, in which a solute is dissolved to form a solution. Water is the most common solvent and is used in the video as the medium in which acids and bases dissolve and dissociate into ions. The role of the solvent is fundamental to the discussion of how substances react and their normality in solution.

Highlights

Introduction to the concepts of equivalent mass and equivalent weight in chemistry.

Explanation of dissociation or ionization of acids and bases in water, using HCl and sodium hydroxide as examples.

The significance of 'x' representing the number of hydrogen or hydroxide ions in a solution.

Calculation of molar mass of H2SO4 and its interpretation in terms of mass per mole.

Introduction to the formula for calculating equivalent mass using molar mass and the value of 'x'.

Illustration of the concept of equivalent mass with the example of H2SO4, resulting in 49 grams.

Explanation of equivalent mass as a measure of the reactive capacity of a molecule.

Calculation of equivalent mass for HCl, sodium hydroxide, and sodium carbonate.

Method to calculate the number of grams equivalent given a mass of a substance.

The relationship between molar mass, equivalent mass, and the reactive capacity of molecules.

Definition and explanation of normality in terms of gram equivalents dissolved per liter of solution.

Comparison between molarity and normality as measures of solution concentration.

Calculation of normality for a solution with given mass and volume, using H2SO4 as an example.

Numerical example calculating the normality of a solution with calcium hydroxide.

Understanding the relationship between normality and molarity using the formula n = m * x.

Advanced numerical example calculating the mass of H2SO4 in a semi-normal solution.

Conclusion summarizing the importance of understanding normality in chemistry.

Transcripts

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Chemistry Basics Equivalent Mass Normality Calculation Acids and Bases Ionization Dissociation Molarity Concentration Chemical Reactions Educational Tutorial