12 Question (3 points) A 94.2 ml sample of 1.00 M NaOH is mixed with 47.1 ml of

Question

12 Question (3 points) A 94.2 ml sample of 1.00 M NaOH is mixed with 47.1 ml of 1.00MH,SO, 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 22.05 °C. After adding the NaOH solution to the coffee cup and stirring the mixed solutions with the thermometer, the maximum temperature measured is 30.10 °C. Assume that the density of the mixed solutions is 1.00 g/mL, that the specific heat of the mixed solutions is 4.18 ng·°C), and that no heat is lost to the surroundings O See page 236 1st attempt See Periodic Table Part 1 (1 pt) 12:16 > 9:50 PM ^ di11/14/2017

Explanation / Answer

Solution- a. The balanced reaction is

2NaOH(aq) + H2SO4(aq) --> Na2SO4(aq) + 2H2O(l)

b. Moles NaOH: 0.0942 L x 1.00M = 0.0942 moles base
Moles H2SO4: 0.0471 L x 1.00M = 0.0471 moles acid
Here the mole ratio base to acid 2:1,
0.0471 moles acid needs double base, so they  both reacts completely into products, Hence nothing is left

c. If no heat lost, q = mass x specific heat x delta T
94.2 mL + 47.1 mL = 141.3mL solution x 1.00g/mL = 141.3g
q = 141.3g x 4.18 J/g C x (30.10 - 22.05)
q = 4754.60 J

Enthalpy change per mole: [ 4754.60J x (1kJ/1,000J)]/ 0.0942 mol
= 50.47 kJ/mol

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