Posted by Sally on Thursday, December 2, 2010 at 3:21pm.
A 5.0-g 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?
- Chemistry - DrBob222, Thursday, December 2, 2010 at 5:37pm
Try reading your question. It needs to be cleaned up. It makes no sense as is.
- Chemistry - j, Sunday, January 25, 2015 at 1:00pm
-q = dH ( dH = change in enthalpy Kj/mol)
Use q=mc(Tf-Ti) and then convert to deltaH
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
Tf-Ti= 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
Answer This Question
More Related Questions
- Chemistry - A 5.0-g Sample of KBr at 25.0 degrees celsius dissolves 25.0 mL of ...
- Chemistry - A 5.0g KBr sample, at 25 degrees celsius, dissolved in 25 ml of ...
- Physics - The water from two buckets is mixed together. One bucket contains 5kg ...
- Chemistry - A 100g sample of water at 90 degrees celsius is added to a 100g ...
- Physics 20 - 1. How much heat energy is required to change 500 grams of water at...
- Chemistry-Thermochemistry (grade 12) - A 65.0 g sample of 0.600 M HI at 18.46 ...
- Chemistry - Calculate the joules of energy involved when 11 grams of water at 10...
- Physics - Please Help! I am having difficulties grasping these concepts. Explain...
- Chemistry - A coffee-cup calorimeter initially contains 125 g water at 24.2 ...
- chemistry - Calculate the enthalpy change for converting 10.0g of ice at -25 ...