Chemistry
posted by Sally
A 5.0g Sample of KBr at 25.0 degrees celsius dissolves in 25.0 degrees celsius 25.0 mL of water also at 25.0 degrees celsius. The final equilibrium temperature of the resulting soltution is 18.1 degrees celsius. What is the enthalpy of of solution in kilojoules per mole of KBr?

DrBob222
Try reading your question. It needs to be cleaned up. It makes no sense as is.

j
q = dH ( dH = change in enthalpy Kj/mol)
Use q=mc(TfTi) and then convert to deltaH
q=mc(TfTi)
q =?
c= 4.814 J/g*C use specific heat of water since its in aqueous sol and we are not told differently
m= total mass= mass KBr + mass water
mass KBr= 5.0 g
*mass of water from density =1g/mL so
(25.0ml) (1g/ml)=25.0g water
m = 25.0g water + 5.0 g KBr = 30.0g
TfTi= 18.1  25.0 = 6.9C
q= (30g) (4.184 J/gC)(6.9C)
q= 1443 J
q = delta H kJ/mol KBr
dH= (q Joules)( 1 kJ/1000 Joules) / mol KBr
*mol KBr = (5.0 g KBr)(1mol KBr) /119g KBr)= 0.042 mol KBr
dH = (1443 J) (1kJ/1000J)/ 0.042 mol KBr)
dH= 34.4 kJ/mol KBr
Respond to this Question
Similar Questions

Chemistry
Calculate the joules of energy involved when 11 grams of water at 10.0 degrees Celsius cools and then freezes at 0.0 degrees Celsius. How many kilocalories are required to raise the temperature of 305 gtams silver from 30 degrees Celsius … 
Chemistry
A 100g sample of water at 90 degrees celsius is added to a 100g sample of water at 10 degrees celsius. The final temperature of the water is which of the following: a) between 50 degrees celsius and 90 degrees celsius b) 50 degrees … 
Chemistry
A coffeecup calorimeter initially contains 125 g water at 24.2 degrees celsius. Potassium bromide (10.5 g), also at 24.2 degree celsius, is added to the water, and after the KBr dissolves, the final temperature is 21.1 degrees celsius. … 
ChemistryThermochemistry (grade 12)
A 65.0 g sample of 0.600 M HI at 18.46 degrees celsius is added to 84.0 g of solution containing excess KOH, also at 18.46 degrees celsius. The final temperature is 21.96 degrees celsius. Calculate the enthalpy of H for the reaction. … 
chemistry
Calculate the enthalpy change for converting 10.0g of ice at 25 degrees Celsius to water at 80 degrees Celsius. The specific heats of ice, water, and steam are 2.09j/g degrees Celsius, 4.18j/g degrees Celsius, and 1.85j/g degrees … 
Chemistry
A 5.0g KBr sample, at 25 degrees celsius, dissolved in 25 ml of water, also at 25 degrees celsius. the final equilibrium temperature of the resulting solution is 18.1 degrees celsius, What is the enthalpy change in J/g and KJ/mole … 
Chemistry
A 5.0g Sample of KBr at 25.0 degrees celsius dissolves 25.0 mL of water also at 25.0 degrees celsius. The final equilibrium temperature of the resulting soltution is 18.1 degrees celsius. What is the enthalpy of of solution in kilojoules … 
Physics 20
1. How much heat energy is required to change 500 grams of water at 100 degrees Celsius to steam at 100 degrees Celsius? 
Physics
Please Help! I am having difficulties grasping these concepts. Explain please! 1. How much heat energy is required to change 500 grams of water at 100 degrees Celsius to steam at 100 degrees Celsius? 
Physics
The water from two buckets is mixed together. One bucket contains 5kg of water at 20 degrees Celsius and the other contains 1kg of water at 80 degrees Celsius. What is the final temperature of the mixture, assuming no heat is lost …