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Thermochemistry, heat calculation. 
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#1
Jan1012, 01:59 PM

P: 28

1. The problem statement, all variables and given/known data
When 10.00 mL of a solution of strong acid is mixed with 100.00 mL of a solution of weak base in a coffeecup calorimeter, the temperature rises from 22.8 oC to 26.8 oC. Determine q for the acidbase reaction, assuming that the liquids have densities of 1.00 g/mL and the same heat capacities as pure water. 2. Relevant equations total volume V=110.0mL change in temperature delta T = 4 mass m = 110.0g heat capacity for water C=75.291J/(mol[itex]\circ[/itex]C q = nC[itex]\Delta[/itex]T q = mC[itex]\Delta[/itex]T 3. The attempt at a solution so I used the formula q = mC[itex]\Delta[/itex]T because with the information given i couldn't find the number of moles and because only the molar heat capacity is given to use i had to find the mass based heat capacity and I found it to be C = 4181.3J/KgK and then found q = 460J which then the computer told me it was wrong. It seemed odd that i had to go find the heat capacity rather than use the one provided. So I feel already there's my first mistake. But i know the formula is right so I can't see why it wouldn't work. However clearly my chemistry isn't that strong so perhaps I'm missing something. Any guidance would be appreciated! Thanks 


#2
Jan1812, 07:20 AM

HW Helper
Thanks
P: 10,537

How did you get 460 J for q=mcΔT when m=0.11 kg, ΔT=4 and c=4181.3 J/kgK?
ehild 


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