Question

30. How much heat energy, in joules, is required to raise the temperature of 1 mole of sulfur from 100. to 500.°C? Specific heat for sulfur is 0.705 J/g-°C. a. 280 b. 1.28 X 104 c. 9.04 X 103 d. 22.6 e. 567 31. What is the final temperature, in °C, when 60.0 g of water at 80°C is mixed with 40.0 g of water at 25°C? The specific heat of water is 4.184 J/g-°C. a. 53 b. 58 c. 70 d. 35 e. 42 32. Calculate the number of grams of ice that will melt, if 1000.0 g of iron at 500°C is dropped into an ice water mixture. The heat of fusion for water is 335 J/g. Specific heat for iron = 0.448 J/g-°C. a. 669 b. 1000 c. 335 d. 13500 e. 1342 33. 100.0 g of water, at 80.°C, is treated with 10. g of ice cubes. The heat of fusion is 335 J/g and the specific heat is 4.18 J/g-°C. Calculate the final temperature, in °C, of the mixture. (hint: treat as 3-component system, hot water, ice, and ice-water) a.0.0 b. 10.6 c. 30.7 d. 65 e. 53.2 34. The Ahº of formation for H2O(g) and H,0(1) is -241.82 and -285.83 kJ/mol, respectively. Calculate the AH of vaporization, in kJ/mol, for water. a. 263 b.44.01 c. - 286 d. - 242 e. -44 35. Calculate the heat of formation of ozone, 0, from the following reaction: Pb(s) + C(s) + O2(g) → Pbco(s) AĦ° = ? The heat of reaction is -841.0 kJ and the heat of formation of lead carbonate is -699.0 kJ/mol. a. -142 b.770 c.-770 d. - 1540 e. 142

Answer 1

30. Ans :- Option (c) " 9.024 x 10³ J " is the correct answer.

Explanation :-

Heat absorb or evolve (q) = Mass of sulfur (m) x Specific heat capacity (C_s) x Change in temperature (ΔT) .........(1)

Because, Number of moles = Given mass in g / Gram molar mass

So,

Mass of Sulfur = Number of moles of Sulfur x Gram molar mass of Sulfur

= 1 mol x 32 g/mol

= 32 g

Put this value in equation (1) :

q = (32 g).(0.705 J/g.⁰C).(500-100) ⁰C

q = (32 g).(0.705 J/g.⁰C).(400) ⁰C

q = 9.024 x 10³ J

So,

Heat absorb (q) = 9.024 x 10³ J

Hence, Option (c) is the correct answer.