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Firefox File Edit View History Bookmarks Yahoo Tools Window Help WN7496: Homework 8 d a search wwnorton.co m/sw/mod/smartwork/view.php?id 354737 LIVE Yahoo Search Print calculator Periodic Table book Question 11 of 14 (1 point) COAST Tutorial Problem A 90.0 mL sample of 1.00 M NaOH is mixed with 45.0 mL of 1.00 M H2SO4 in a large Styrofoam coffee cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 21.30C. After adding the NaOH solution to the coffee cup and stirring the mixed solutions with the thermometer the mixed solutions is 1.00 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g. C), and that no heat is lost to the surroundings (a) Write a balanced chemical equation for the reaction that takes place in the Styrofoam cu (b) Is any Na or H2SO4 left in the Include phases in the balanced chemical Styrofoam cup when the reaction is over? equation. Type an open parenthesis to add a phase. Phases should not be subscripted. Use the left and right arrow kevs to move the cursor Yes out of a superscript or subscript in the module No (c) Calculate the enthalpy change per mole of H2SO4 in the reaction. Check Answer View S tion Hin Progress Record my Grade Activity Grande. Points Possible 63% D Fri Mar 13 12 23 PM a E CHEM LAB ENGR 1201 Important olde Pictures Presentatio n 3 Screen Shot 2015...6 PM Screen Shot 2015...1 PM Lab Rebort M...n.pdf

Explanation / Answer

Hi,

A) This is a classic neutralization between a strong base (NaOH) and a strong acid (H2SO4), resulting in the formation of a salt (Na2SO4) and water:

2NaOH (aq) + H2SO4 (aq) --> Na2SO4 (aq) + 2H2O
B) Moles NaOH: 0.090 L x 1.00M = 0.090 moles base
Moles H2SO4: 0.045 L x 1.00M = 0.045 moles acid
Mole ratio base to acid 2:1,
0.045 moles acid needs x2 base, there is enough
for both to completely react into products, so none left

C) If no heat lost, q = mass x specific heat x delta T
90 mL + 45 mL = 135mL solution x 1.00g/mL = 135g
q = 135g x 4.18 J/g C x (31.9 - 21.3)
q = 5981.6 J
Moles H2SO4: 0.045 moles
Enthalpy change per mole: [ 5981.6 J x (1kJ/1,000J)]/ 0.045 mol
= 132.9 kJ/mol

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