Calculating the Concentration of N/5 HCl After Removal of 3.65g

  • Context: Chemistry 
  • Thread starter Thread starter xiphoid
  • Start date Start date
  • Tags Tags
    Concentration Hcl
Click For Summary

Discussion Overview

The discussion revolves around calculating the concentration of a hydrochloric acid (HCl) solution after the removal of a specific mass of HCl following the boiling of the solution. The context includes concepts of concentration, molarity, and normality, with a focus on the implications of these definitions in the calculation process.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents a homework problem involving the boiling of 1 liter of N/5 HCl and the subsequent removal of 3.65g of HCl, asking for the resulting concentration.
  • Another participant suggests using the definition of concentration and prompts the original poster to consider the amount of solvent and moles of HCl before and after boiling.
  • A different participant emphasizes the importance of understanding molality and suggests looking up the relevant equation, while also indicating that the original poster should already be familiar with it.
  • One participant corrects a previous statement about molality, clarifying that the focus should be on molarity, and discusses the historical context of normality and its complexities in chemical calculations.
  • A participant expresses confusion about the term "normality" and acknowledges a previous misunderstanding regarding molarity.

Areas of Agreement / Disagreement

There is no consensus on the approach to solving the problem, with participants discussing different aspects of concentration definitions and expressing confusion about terminology. The discussion remains unresolved regarding the correct method to calculate the concentration after the removal of HCl.

Contextual Notes

Participants mention the historical context of normality and its relevance in certain fields, indicating potential limitations in understanding modern terminology and practices in chemistry.

xiphoid
Messages
57
Reaction score
0

Homework Statement


On boiling 1litre of N/5 HCl, the volume of the aqueous solution decreases to 250ml. If 3.65g of HCl is removed from solution, then the concentration of resulting solution becomes?
N/5
N/2.5
N/20
N/10

Homework Equations


HCl=36.5g/ mol


The Attempt at a Solution


no idea
 
Physics news on Phys.org
Use concentration definition. You start with 1L of solution - how much solvent? How many moles of HCl? How much solvent after the boiling? How much HCl?
 
At this point you should know about Molality.
There should be an equation for it (Molality) in your textbook... I think that Borek wants you to look it up rather than me tell you what the equation is. You'll really need to memorize what the equation is anyway (don't worry, it's straight forward).
 
ohms law said:
At this point you should know about Molality.
There should be an equation for it (Molality) in your textbook... I think that Borek wants you to look it up rather than me tell you what the equation is. You'll really need to memorize what the equation is anyway (don't worry, it's straight forward).

not molality (m) but molarity (M). There is a subtle, but important difference. And I do not think that that is where your problem lies because normality (N) is a "drop in" substitute for molarity (M) for monofunctional reagents.

"Equivalent weights" and "Normality" are no longer used by chemists (since a IUPAC ruling in the mid 1960s), but they have lingered on in engineering and in sections of the chemical industry. They become problematic because of ambiguities, where, for example, nitric acid as oxidant may have functionalities of 1, 3, 4, or 5, for its various oxidation reactions, meaning that the exact same solution could be regarded as 0.1 N, 0.3 N, 0.4 N, or 0.5 N!
 
oops, sorry. That's what I meant (Molarity). Damn.
I've never heard of "normality" before.

Molality (m=mol/kg) is what we were doing about two weeks ago, so... *shrug*
 

Similar threads

Concentration of the resulting solution in this question
  • · Replies 1 ·
Replies
1
Views
2K
How Do You Calculate NaCH3COO Concentration and Predict pH at Equivalence Point?
  • · Replies 4 ·
Replies
4
Views
4K
How Do You Calculate Equilibrium Concentrations in a Redox Reaction?
  • · Replies 2 ·
Replies
2
Views
4K
How Can Ammonia Be Used to Adjust the pH of a Highly Acidic Solution?
  • · Replies 11 ·
Replies
11
Views
4K
Finding a rock porosity change after an acid mix treatment
  • · Replies 1 ·
Replies
1
Views
2K
Calculating the molar concentration of H3O+ and pH of solutions
  • · Replies 4 ·
Replies
4
Views
6K
Expected concentration of fluoride released from PFAA
  • · Replies 3 ·
Replies
3
Views
2K
Electrochemistry, emf vs HCL concentration
  • · Replies 1 ·
Replies
1
Views
3K
Calculate the HCl concentration in H2O from the conductivity
  • · Replies 5 ·
Replies
5
Views
6K
Determine volume of HCl added to propionic acid to get pH=1
  • · Replies 1 ·
Replies
1
Views
5K