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how do I figure out the final temperature? The AH for the solution process when

ID: 893159 • Letter: H

Question

how do I figure out the final temperature? The AH for the solution process when solid sodium hydroxide dissolves in water is 44.4 kj/mol. What amount of NaOH dissolves in 250.0g of water in a coffee-cup calorimeter that causes a temperature increase from 24.0 degree C to 39.0 degree C? Assume the solution has the same specific heat as liquid water (4.18 J/g degree C). A 5.00g sample of copper has an initial temperature of 95 degree C The initial temperature for a 25.0g sample of water is 22.5 C What is the final temperature of this mixture? Specific heat of copper is 0.385 |/g ^aC The combustion of titanium with oxygen produces titanium (IV) oxide: Tl (s) o2 (g) -> TIo^2 (s) f 1.750g of titanium is combusted In a bornb calorimeter, the temperature of the calorimeter increases from 25.0*C to 93.6 degree C. If in a separate experiment, the heat capacity of the calorimeter is determined to be 9.84 k|/ degree C calculate the heat of reaction for the combustion per mole of Ti (kl/mol).

Explanation / Answer

10 .

specific heat of water s = 4.18 J/(gC)

mass of water = 250 grams

DT = 39-24 = 15

q absorbed by water = m*s*DT

           = 250*4.18*15 = 15.675 kj

from the data 1 mole = 44.4 kj

so that ? mole    = 15.675 kj

         = 15.675/44.44 = 0.3528 mole

mass of NaOH = 0.3528*40 = 14.112 grams


11.

qmetal lost = q water absorbed

m*s*DT = m*s*DT

5*0.385*(95-Tf) = 25*4.18*(Tf-22.5)

Tf= final temperature of mixer = 23.811 c

12.

heat capacity of calorimeter = 9.84 kj/C

heat absorbed = 9.84*(93.6-25) = 675.024 kj

No of moles of Ti = 1.75/47.867 = 0.03656 mole


heat of reaction = 675.024/0.03656 = 18463.457 kj/mol