Q1 emistry: An Introduction to General, Organic and Biological dition by Timberl
ID: 559044 • Letter: Q
Question
Q1
emistry: An Introduction to General, Organic and Biological dition by Timberlake as well as review the online resources in th tempting the problems in this tutorial h. For the reaction: 25() + 302(g) 2SO3(g) +-790 kJ (a) Is the reaction endothermic or exothermic? (b) How many kJ are released when 1.5mol of S reacts (c) How many kJ are released when 125g of SOs is formed? (d) What is the AH, in kilojoules, for the following reaction: 2SOdg) 2S(s) +302(g) exothermic? (e) Is the reaction in part (d) endothermi 2. 147.5mL (6oz) of Coca Cola@ is placed in a calorimeter containing 1 an initial temperature of 25°C. After the completion of the combus Cola® the temperature of the water rose to 65 C. (a) What is the energy value in kcal of the 5 oz of soda?Explanation / Answer
1) The equation is
2S + 3 O2 --------------> 2SO3 + (-790kJ)
As the reaction is given with energy given in the products , energy is liberated in the reaction . that is the reason it is represented with negative sign.
a) the reaction is exothermic (-790kJ)
b)when 2 moles of s are reacted 790 kJ is released. thus
when 1.5 mole of S reacted ,
the heat liberated = 1.5x790 kJ/2
= 592.5 kJ
c) According to the reaction 2 moles of So3 formation gives out 790 kJ
hence 125/80 moles of SO3 give s =( 125/80) 790/2 kJ
= 617.19 kJ of heat
d) When the equation is reversed, the sign of delta H is also reversed. In other words, for the reverse reaction it becomes endo thermic.
delta H for reaction
2SO# ------------> 2S + 3O2 is +790kJ
e) It is endo thermic.
If the forward reaction is exothermic, the backward ereation is endothermic.
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