M Ch. 10 (Hybridization and x calculate the heat released x ezto.mheducation.com

ID: 870295 • Letter: M

Question

M Ch. 10 (Hybridization and x calculate the heat released x ezto.mheducation.com /hm.tpx Chemistry 1320: Spring 2015 CHEMISTRY Ch. 10 (Hybridization and Delocalized Bonds) and Ch. 6 Thermochemistry v next pre Question #9 (of 10) 9. value points 20 1 out of 5 attempts NetCalculator Enter your answer in the provided box. Assistance Calculate the heat released when 1.00 L of Ci20g) with a density of 1.88 g/L reacts with an Check My Work excess of sodium metal at 25 C and 1 atm to form sodium chloride Print kJ Question Help Report a Problem references Hill Education. All rights reserved. Surface b43 Allison Mikesell instructions I help save & exit submit assignment 5:50 PM 5/5/2015

Explanation / Answer

Mass of Cl2 = 1.88g/L x 1L = 1.88g

Number of mol = 1.88g/71g/mol= 0.0265 mol Cl2

Substance

dHof

kJ/mol

Cl2(g)

Na(s)

NaCl(g)

-181

NaCl(s)

-411

Assume the product is NaCl(s).

Cl2(g) + 2 Na(s) = 2NaCl(s)

dHo = 2(-411) - 2x0 - 0 = - 822 kJ per reaction, i.e per mol Cl2.(see table)

Heat released = - 822 kJ/molCl2 x 0.0265 mol Cl2 = - 21.8 kJ

(as heat released could be also with +)

10.

From 3 molN2 and 9 mol H2, the product is 6 mol NH3.

3+9-6= 6 mol less

Molar volum at 25C and 1 atm is 22.4L

The contraction dV is -6x22.4 = -134.4L = -0.1344 m3

1 atm = 101 325 Pa = 101 325 N/m2

w = - p x dV = - 101 325 N/m2 x (-0.1344 m3 )= 13 618 J

dU = 3 x dHorxn + w

= 3 mol x (-92.6 kJ/mol) + 13.6 kJ

= - 277.8 kJ + 13.6 kJ =

= - 264.2 kJ