If V1 x M1 = V2 x M2, then why here 2V1 x M1 = V2 x M2?

  • Thread starter Indranil
  • Start date
In summary, the conversation discusses two chemical reactions and the use of the equation V1 x M1 = V2 x M2. However, the user is advised to understand the concepts behind the equation and not rely on it blindly. They are encouraged to revise their understanding of molecules, moles, molarities and chemical formulae from their textbook.
  • #1
Indranil
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1. The problem statement, all variables, and given/known data
In the first rection, NaOH + HCl = NaCl + H2O
From the first rection, we can write V1 x M1 = V2 x M2
In the second rection, 2NaOH + H2SO4 =Na2SO4 + H2O
From the second rection, Can we write V1 x M1 = V2 x M2?

Homework Equations


1. NaOH + HCl = NaCl + H2O
2. 2NaOH + H2SO4 =Na2SO4 + H2O

The Attempt at a Solution


From the second rection, I wrote the equation V1 x M1 = V2 x M2 but my book says I am wrong.
 
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  • #2
Indranil said:
1. The problem statement, all variables, and given/known data
In the first rection, NaOH + HCl = NaCl + H2O
From the first rection, we can write V1 x M1 = V2 x M2
In the second rection, 2NaOH + H2SO4 =Na2SO4 + H2O
From the second rection, Can we write V1 x M1 = V2 x M2?

Homework Equations


1. NaOH + HCl = NaCl + H2O
2. 2NaOH + H2SO4 =Na2SO4 + H2O

The Attempt at a Solution


From the second rection, I wrote the equation V1 x M1 = V2 x M2 but my book says I am wrong.

Your equation 2 is telling you the two molecules of NaOH react with one of H2SO4!

Do not rely too much on remembering blind formulae without understanding what they mean.
 
  • #3
epenguin said:
Your equation 2 is telling you the two molecules of NaOH react with one of H2SO4!

Do not rely too much on remembering blind formulae without understanding what they mean.
According to you what will be the solution for the second reaction?
 
  • #4
Indranil said:
According to you what will be the solution for the second reaction?

Why don't you try to follow the stoichiometry and find out what the right approach is?

m1v1=m2v2 is one of the worst things taught in schools. Even if it is SOMETIMES true, people apply it blindly everywhere. Just forget you were ever taught it.
 
  • #5
Sorry, it sounds as though you need to revise from your books quite elementary ideas of what molecules, moles, molarities and chemical formulae are and mean.
We help out here with misunderstandings of textbook material, but we do not write the textbooks, i.e. cannot do everything from zero, and we do not spoonfeed or give answers. (overlapped Borek's post.)
 

1. Why is there a 2 in front of V1 in the second equation?

The 2 in front of V1 represents a doubling of the original volume, indicating that the resulting volume will be twice as large as the original volume.

2. How is this equation derived?

This equation is derived from the law of conservation of mass, which states that the total mass of a closed system remains constant over time. In this case, the volume and molarity of a solution are directly related to its mass, so the equation shows that the initial and final masses must be equal.

3. Why is it important to use the correct units in this equation?

The units used in this equation (volume in liters and molarity in moles per liter) are important because they correspond to the units used to measure mass. Using the correct units ensures that the equation accurately reflects the law of conservation of mass.

4. Can this equation be applied to all solutions?

Yes, this equation can be applied to any solution where the law of conservation of mass applies. However, it is important to note that this equation assumes that the solution is well-mixed and has a constant density throughout.

5. What are the practical applications of this equation?

This equation has many practical applications in various fields such as chemistry, biology, and environmental science. It can be used to calculate the concentration of a solution, determine the amount of solute needed to make a solution, and predict the outcome of a chemical reaction. It is also useful in understanding and predicting the behavior of solutions in natural systems.

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