Chemistry Clarification. Thats it
"In a student lab, 60.0mL of 0.700mol/L sodium hydroxide solution was neutralized with 40.0mL of excess sulfuric acid solution. The temperature increased by 5.6 C."
Calculate the molar enthalpy of neutralization for calcium hydroxide.
I got -44.6 kJ/mol as the answer, but my textbook has -5.57 kJ/moL.
I'm wondering if I'm wrong, or if this is just another one of my textbook's many typos.
December 16, 2012
9 Comments • Newest first
[quote=aznseal]Use q=mcdeltaT where q is your answer, m is mass, c is specific heat, delta T is change in temperature.
You have 0.042 moles of NaOH (.700 M * .060 L).
Next, if you use q=mcdeltaT, you have to assume the solution is water (acid/base neutralization creates H2O), and H2O has a specific heat of 4.186 J/g * C. Since you have 60 mL of base and 40 mL of acid, the total is 100 mL so assume 100 mL of water, so assume a mass of 100 g. Then q = (100g)(4.186)(5.6) = 2344.16 J. That's for 0.042 moles though. If you use a ratio for 1 mole, you get 55813.3 J.
Source: I teach chemistry.[/quote]
ohhh.
Had to add the masses.
Didn't do that.
Aight, thanks.
Edited my original post with the work.
@ZzXxskyxXzZ: You use q=mcdeltaT.
I'm pretty sure Q=MCdeltaT isn't the only thing you use here, or if you use it at all.
[quote=aznseal]Use q=mcdeltaT where q is your answer, m is mass, c is specific heat, delta T is change in temperature.[/quote]
Yah.
I used this equation: 2NaOH + H2SO4 > 2H2O + Na2SO4
And I got -44.6 kJ/mol as the answer.
I'm nearly completely certain that that's the answer; I just needed some clarification/
Use q=mcdeltaT where q is your answer, m is mass, c is specific heat, delta T is change in temperature.
You have 0.042 moles of NaOH (.700 M * .060 L).
Next, if you use q=mcdeltaT, you have to assume the solution is water (acid/base neutralization creates H2O), and H2O has a specific heat of 4.186 J/g * C. Since you have 60 mL of base and 40 mL of acid, the total is 100 mL so assume 100 mL of water, so assume a mass of 100 g. Then q = (100g)(4.186)(5.6) = 2344.16 J. That's for 0.042 moles though. If you use a ratio for 1 mole, you get 55813.3 J.
Source: I teach chemistry.
[quote=lncognito]Books [b]almost[/b] always right.[/quote]
Not always though.
And these Nelson textbooks seem to be marred with them, when compared with textbooks from other publishers.
draw a picture of walter white
[quote=cchpm]Text your friends and ask what they got.[/quote]
They're all working/having lives ATM, and probably won't be doing it until 10-11 PM.
Text your friends and ask what they got.