Question

1. explain the difference between heat of neutralization and enthalpy of neutralization.

2. You mix 50.0 mL of a weak monoprotic acid with 50.0 mL of NaOH solution in a coffee cup calorimeter. Both solutions (and the calorimeter) were initially at 22.0^OC. The final temperature of the neutralization reaction was determined to be 22.5^OC.

a)What is the total amount of heat evolved in this reaction? Show all work. (3 points)

b) If 0.135 moles of the monoprotic acid were neutralized in this reaction, what is the molar heat of neutralization (enthalpy) for this reaction? (3 points)

3. Imagine you are at a local water park on a hot summer day and your feet begin to get hot from the cement.Looking ahead, you notice that there are two paths you can take to your favorite waterslide. One path is comprised of sand while the other path consists of water.You opt for the water path because you know it will be cooler on your feet.Assuming that both paths were exposed to the same heatsource (the sun) and that both paths have the same mass, explain why water does not get as hot as sand.

Answer 1

1. explain the difference between heat of neutralization and enthalpy of neutralization.
they are the same. heat of neutralization is usally the heat measured in an experiment of neutralization. The nethalpy of neutralization is the enthalpy change when there is neutralization. Recall that Heat = Q and Enthalpy = H. If constant pressure is assuemd, then Q = H

2. You mix 50.0 mL of a weak monoprotic acid with 50.0 mL of NaOH solution in a coffee cup calorimeter. Both solutions (and the calorimeter) were initially at 22.0OC. The final temperature of the neutralization reaction was determined to be 22.5OC.

a)What is the total amount of heat evolved in this reaction? Show all work. (3 points)

V = 50 ml of HA

V = 50 ml of NaOH

Ti = 22°C

Tf = 22.5°C

m = 50+50 = 100g

Cp = 4.184 J/gC

Q = m*cp(Tf-Ti) =100*4.184*(22.5-22)= 209.2 J

b) If 0.135 moles of the monoprotic acid were neutralized in this reaction, what is the molar heat of neutralization (enthalpy) for this reaction? (3 points)

n = 0.135 mol of HA

find H/n

H = 209.2 J --> 0.135 mol

H = 209.2/0.135 = 1549.6 J/mol = 1.55 kJ/mol

3. Imagine you are at a local water park on a hot summer day and your feet begin to get hot from the cement.Looking ahead, you notice that there are two paths you can take to your favorite waterslide. One path is comprised of sand while the other path consists of water.You opt for the water path because you know it will be cooler on your feet.Assuming that both paths were exposed to the same heatsource (the sun) and that both paths have the same mass, explain why water does not get as hot as sand.

Sand has a lower Cp, meaning it will transfer heat faster, there will change temperature faster with your skin. Also, sand has color, so radiation will heat higher

Water has a higher Cp, meaning it will not change temperature drastically with your skin. It also is colorless so it wont get hot Also, water can vaporize molecules so it will take out heat energy from the bulkg water, therefore it stays at lower T