What is the Difference Between Gram Equivalent and Equivalent Weight

Both gram equivalent and equivalent weight represent the mass of a substance that can participate in a single reaction with a fixed amount of another substance. Although they are very closely related to concepts, there is a difference between gram equivalent and equivalent weight.

What is the difference between gram equivalent and equivalent weight?  Equivalent weight can be in any unit, while gram equivalent specifically refers to grams.

Key Areas Covered

1. What is Gram Equivalent 
      – Definition, Features 
2. What is Equivalent Weight
      – Definition, Features 
3. Similarities Between Gram Equivalent and Equivalent Weight
      – Outline of Common Features
4. Difference Between Gram Equivalent and Equivalent Weight
      – Comparison of Key Differences
5. FAQ: Gram Equivalent and Equivalent Weight
      – Answers to Frequently Asked Questions

Key Terms

Gram Equivalent, Equivalent Weight

What is Gram Equivalent

A gram equivalent is a specific way to express the reactive capacity of a substance in chemistry. It represents the mass of a substance that can combine with or displace a fixed amount of another substance in a reaction. Gram equivalent is the equivalent weight, but specifically expressed in grams. Calculating gram equivalents is relatively straightforward. Moreover, the regular molecular weight (mass of one molecule) of the substance is divided by its valence (the number of electrons it can gain, lose, or share in a reaction) is the calculation of gram equivalent.

There are many applications related to the gram equivalent. For example, in stoichiometry, knowing the gram equivalent of reactants allows you to calculate the amount of product formed or vice versa. By knowing the gram equivalent of a solute, you can determine its normality in a solution.

What is Equivalent Weight

Equivalent weight refers to the mass of a given substance that will combine with or displace a fixed quantity of another substance. This fixed amount is typically:

• 1.008 grams of hydrogen
• 8.0 grams of oxygen

The equivalent weight is calculated by dividing the molar mass of a substance by its valence. This gives the mass that’s equivalent to one “reaction unit” of the substance.

Equivalent weight has several important applications. It is used in stoichiometry to calculate the exact amounts of reactants needed and products formed in a reaction. Moreover, in gravimetric analysis, it is used to determine the mass of a specific element in a compound by analyzing the weight of the precipitate formed in a reaction.

Similarities Between Gram Equivalent and Equivalent Weight

• They both represent the mass of a substance that can participate in a single reaction with a fixed amount of another substance.
• Moreover, they are used in stoichiometric calculations to determine quantities of substances involved in chemical reactions.

Difference Between Gram Equivalent and Equivalent Weight

Definition

• Equivalent weight is a more general term referring to the mass of a substance (element, ion, or compound) that can combine with or displace a fixed amount of another substance in a reaction. Meanwhile, gram equivalent is a specific type of equivalent weight, referring to the mass, in grams, of one equivalent of a substance.

Measurement

• Equivalent weight can be expressed in any unit of mass, like grams (g), kilograms (kg), or even atomic mass units (amu), while gram equivalent is basically the equivalent weight expressed in grams.

Conclusion

In conclusion, gram equivalent and equivalent weight are closely related concepts used to express a substance’s reactive capacity in a chemical reaction. Equivalent weight can be in any unit, while gram equivalent specifically refers to grams. Thus, this is the main difference between gram equivalent and equivalent weight

FAQ: Gram Equivalent and Equivalent Weight

1. Is equivalent weight the same as gram equivalent?

No, Equivalent weight is the general term used to describe the mass of a substance that can combine with or displace a fixed quantity of another substance in a chemical reaction. Gram equivalent, on the other hand, is the term that states the unit of the equivalent weight, which is grams.

2. What is the difference between normality and gram equivalent weight?

Gram equivalent is a specific type of equivalent weight. Normality, on the other hand, is the number of gram equivalents of a solute dissolved per litre of solution. This is the main difference between gram equivalent and normality.

3. What is the formula for eq weight?

Eq. Wt. = Molecular Weight / Valence

Molecular weight is the total mass of one molecule of the substance, typically expressed in grams per mole (g/mol). Valence is the combined capacity of an atom or ion.

4. What is the law of gram equivalence?

In a chemical reaction, the number of gram equivalents of each reactant consumed will be equal to the number of gram equivalents of each product formed. This is the core idea of the law of gram equivalence.

5. How to calculate the gram equivalent?

Steps to calculate gram equivalent are as follows.

1. Identify the molecule or ion for which you want to calculate the equivalent weight.
2. Find the molecular weight of the substance from the periodic table or a reliable source.
3. Determine the valence of the substance based on the type of reaction it’s involved in (acid, base, redox, etc.).
4. Plug the molecular weight and valence into the formula: Eq. Wt. = MW / Valence
5. Calculate the result. The gram equivalent will be in grams (g).

Reference:

1. “Equivalent Weight.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “Chemicals in the Environment” By André Künzelmann – Helmholtz Centre for Environmental Research (UFZ) (CC BY-SA 3.0) via Commons Wikimedia