Confusing Stoichiometry Question

[pure kirk]

I got this question as an example question and I have no clue on how to solve part B

Chlorine can be produced by the reaction:
2KMnO4 + 16HCl ->2KCl + 2MnCl2 + 5Cl2 + 8H2O
(a)What mass of KMnO4 is required to produce 2.5 L of Cl2 gas measured at STP?

For part A I got 7.05 g ( 0.044615 moll)
(b) Calculate the volume of commercial hydrochloric acid required (Commercial grade hydrochloric acid is 36.0% HCl by weight, and has a density of 1.18 g mL^(–1)).

 

[DrClaude]

I got this question as an example question and I have no clue on how to solve part B

Chlorine can be produced by the reaction:
2KMnO4 + 16HCl ->2KCl + 2MnCl2 + 5Cl2 + 8H2O
(a)What mass of KMnO4 is required to produce 2.5 L of Cl2 gas measured at STP?

For part A I got 7.05 g ( 0.044615 moll)

That is much too low. Please show your calculations.

(b) Calculate the volume of commercial hydrochloric acid required (Commercial grade hydrochloric acid is 36.0% HCl by weight, and has a density of 1.18 g mL^(–1)).

Can you start by figuring what mass of HCl you need?

 

[Borek]

That is much too low. Please show your calculations.

I got 7.051 g as well:

 

[DrClaude]

I'm sorry for the mistake. I used the density of Cl₂ given by WolframAlpha, which is much higher.

 

[Borek]

Looks like they are listing density of a liquid Cl₂ - which doesn't make much sense at STP...

 

[DrClaude]

Looks like they are listing density of a liquid Cl₂ - which doesn't make much sense at STP...

Indeed. Very strange.

I feel ashamed because I didn't follow the rule that I always tell my students: when you get a numerical answer, always try to figure out if the order of magnitude makes sense. I should've checked with the ideal gas law...