Consider the reaction: 2HCl(aq) + Ba(OH)2(aq) ! BaCl2(aq) + 2 H2O(l) deltaH = \"
ID: 878766 • Letter: C
Question
Consider the reaction: 2HCl(aq) + Ba(OH)2(aq) ! BaCl2(aq) + 2 H2O(l) deltaH = "118 kJ
A) Calculate the heat produced when 700.0 mL of 0.500 M HCl is mixed with 300.0 mL of 0.500 M Ba(OH)2. Note: One of the solutions is the limiting reagent.
B) Calculate the final temperature if both solutions were initially at 25.0° C, and they were mixed together in a calorimeter with a heat capacity of 180.3 J/C° Note: The density specific heat capacity of the solution are the same as that of water: D = 1.00 g/cm3 and C = 4.184 J /g•°C
Explanation / Answer
HCl moles = 0.500 x 700 /1000 =0.35
Ba(OH)2 moles= 0.5 x300 / 1000= 0.15
2HCl(aq) + Ba(OH)2(aq) -----------------> BaCl2(aq) + 2 H2O(l) deltaH = "118 kJ
2mole ------------> 1 mole Ba(OH)2 --------------------> 118 kJ
0.35 ---------------> 0.15 ---------------------------------------> ?
here limiting reagent Ba(OH)2 . the product depends on moles of Ba(OH)2.
1 mole Ba(OH)2 ---------------------> 118 kJ
0.15 mole --------------> ??
heat produced = 118 x 0.15
= 17. 7 kJ
2) reaction between acid +base gives H2O . so the mass of H2O is needed
for 1 mole Ba(OH)2 -----------------> 2 mole H2O
0.15 mole ------------------------> ?
moles of water = 2 x 0.15
= 0.3
weight of water = 0.3 x 18 = 5.4 g
Q = m Cp (T2-T1)
17.7 = 5.4 x 4.184 x (T2 - 25)
T2 = 25.78 Co
final temperature = T2 = 25.78 Co