5.00g of urea is dissolved in 250.0ml of water at 30.0 degrees celcius in a coff

Question

5.00g of urea is dissolved in 250.0ml of water at 30.0 degrees celcius in a coffee cup calorimeter. When this is done, 27.6kJ of heat is absorbed. *refer to picture* Directions: You can use any resource, but one that "breathes". The quiz is due to me by the date stated on BB. If it is turned in later than this date, you will earn a 0 : It can be turned in electronically or paper form. Answer the folowing questions (10 points) 1. 1. 5.00 g of urea, (NH,),CO is dissolved in 250.0 mL of water(density 1.00 g/mL) at 30.0°C in a coffee cup calorimeter. When this is done, 27.6 k3 of heat is absorbed(that is the reaction is absorbing the heat). (5 points) a. Is the solution process(the reaction) exothermic or endothermic? b. What is qte c. What is the final temperature of the solution(specific heat constant of water is 4.18 3/g.°c)? 2. How many mL of water at 10.0 must be added to 75.0 mL of water at 35.0 to obtain a final temperature of 19.0°C(assume that no heat is lost to the surroundings and that density of water 1.00 g/mL)? (5 points) 104025099-di-content-rid-110654036.2/courses/LF298.CHM.111.1WOV.FA17/014 docs

Explanation / Answer

Q1)

a) As heat is absorbed the process is ENDOTHERMIC

b) q water = heat given by water

= -the heat absorbedby the reaction =- 27.6kJ

c) -q water = mass of water x specific heat of water x difference in temperature

-27.6 x1000 J = 250g x 4.18J/g.C (t-30)

Thus final temperature t =3.588 C

Q2) heat absorbed by cold water = heat given by hot water

mass x 4.18J/g.C x (19-10) = 75g x 4.18J/g.C ( 19-35)

Thus mass of water =133.33 g

Related Questions

Navigate

• Browse (All)
• Browse 5
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.