Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Exam 2 Practice Problems - Chemistry II | CH 126, Exams of Chemistry

Material Type: Exam; Class: Chemistry II; Subject: Chemistry; University: Emporia State University; Term: Spring 2000;

Typology: Exams

Pre 2010

Uploaded on 08/06/2009

koofers-user-kpl
koofers-user-kpl 🇺🇸

10 documents

1 / 7

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
CH 126 NAME:
Spring 2000
EXAM #2
1) Below is a graph showing the titration of 50.00 mL of an HA (a monoprotic acid)
solution with 0.1334 M NaOH. Use this graph to answer the following questions.
a) Estimate the Ka of HA? (5 points)
b) What is the initial concentration of the HA solution (the concentration before any
NaOH was added). (7 points)
Titration of HA with 0.1334 M NaOH
0
2
4
6
8
10
12
14
0 10 20 30 40
Volume NaOH Adde d (mL)
pH
pf3
pf4
pf5

Partial preview of the text

Download Exam 2 Practice Problems - Chemistry II | CH 126 and more Exams Chemistry in PDF only on Docsity!

CH 126 NAME:

Spring 2000 EXAM #

  1. Below is a graph showing the titration of 50.00 mL of an HA (a monoprotic acid) solution with 0.1334 M NaOH. Use this graph to answer the following questions. a) Estimate the Ka of HA? (5 points) b) What is the initial concentration of the HA solution (the concentration before any NaOH was added). (7 points)

Titration of HA with 0.1334 M NaOH

Volume NaOH Added (mL)

pH

  1. Calculate [H+], [OH-], pH, and pOH for 0.500 M solutions of the following? a) KOH (8 points) [H+]: [OH-]: pH: pOH: b) NaCN (8 points) [H+]: [OH-]: pH: pOH: c) HNO 2 (8 points) [H+]: [OH-]: pH: pOH:
  1. What is the pH of a buffer prepared by combining 200.0 mL of 0.366 M HNO 2 with 300.0 mL of 0.288 M NaNO 2? (8 points)
  2. Write the equilibrium constant expression, K, for each of the following reactions. (3 points each) a) 2H 2 S(g) + 3O 2 (g) = 2H 2 O(g) + 2SO 2 (g) b) H 2 (g) + FeO(s) = H 2 O(g) + Fe(s)
  3. For the reaction below determine the effect of: PCl 5 (g) = PCl 3 (g) + Cl 2 (g) a) adding PCl3, (3 points) b) increasing the pressure on the system by decreasing the volume, (3 points) c) removing Cl2. (3 points)
  1. A mixture of 0.100 mol of NO, 0.050 mol of H 2 , and 0.100 mol H 2 O is placed in a 1.00 L vessel. At equilibrium, [NO] = 0.062 M. Use the equilibrium reaction below to answer the following questions. 2NO(g) + 2H 2 (g) = N 2 (g) + 2H 2 O(g) a) Calculate the equilibrium concentrations of H 2 , N 2 , and H 2 O. (8 points) b) Calculate Kc. (5 points)
  2. For the equilibrium reaction below K = 6.0 x 10-5. Use the information provided to answer the following questions. (4 points each)

N 2 (g) + O 2 (g) = 2NO 2 (g)

a) Determine the “direction” of reaction if the reaction mixture contains [N 2 ] = 0.900 mol/L, [O 2 ] = 0.800 mol/L, [NO 2 ] = 0.0050 mol/L.

b) What is K for the reaction 2NO 2 (g) = N 2 (g) + O 2 (g)?

Henderson-Hassalbalch Equation:

Acid Ka HCN 2.1 x 10- HNO 2 5.1 x 10-         [acid] [base] pH pKa log