Please do #6 part a and B Name uS II State Section Prelab Questions 1. What is t
ID: 588941 • Letter: P
Question
Please do #6 part a and BName uS II State Section Prelab Questions 1. What is the temperature of melting ice? 32 F Date 2. Why do we use nested foam cups? For more Srability 3. In Part B, why does the mass of the water decreasert easco iSt or the watex was oS 4. The heat of fusion of water and the heat of vaporization of nitrogen are given in the following Complete the table by showing the problem sétup (with unrounded answer) used to convert the given values to units of J/g, cal/mol, and J/mol. Write the rounded answer in the blank provided water, 13yt12 || 80.0 cal/g . Molar heat of fusion of cal/mol rmol water Heat of vaporization of nitrogen, AH 74 cal.ISS Molar heat of vaporization 2 of nitrogen, N cal/mol /mol 103 cal; 1.90 x 101) 5. How much heat is needed to melt 56.77 g of ice at 0°C? b. In J? (3.63 x 10' cal; 1.52 × 10 How much heat is needed to vaporize 2.72 moles of nitrogen? a. In cal? 5,5 x 2.72 Kylmol 6. b. In J? 7. What is the boiling point of nitrogen (in C)?las &c; Instructor's Initials Lab 13 149
Explanation / Answer
6.
a) molar mass of N2 = 28.0134 gm/lmole then 2.72 mole of nitrogen = 2.72 X 14.0134 = 76.196 gm
Heat of vaporization of nitrogen = 47.6 cal / gm then for 76.196 gm of nitrogen heat of vaporization =
76.196 X 47.6 = 3627 Cal = 3.63 X103 cal
Heat of vaporization of 2.72 mole nitrogen = 3.63 X103 cal
b) 1 cal = 4.184 joule
then 3.63 X103 cal = 3.63 X103 X 4.184 = 1.52 X 104 J
Heat of vaporization of 2.72 mole nitrogen = 1.52 X 104 J