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Science-Related Homework Help Chemistry Topic started by: tater218 on Apr 14, 2012



Title: A 5.00-mL sample of a phosphoric acid solution of unknown concentration is titrated with a 0.1221 M
Post by: tater218 on Apr 14, 2012
Part 1 of 1 -   27.0/ 50.0 Points
Question 1 of 12    4.0/ 4.0 Points
A 0.15 M solution of BaCl2 contains:

A. 0.30 M Ba2+ ions and 0.30 M Cl- ions.   

B. 0.30 M Ba2+ ions and 0.15 M Cl- ions.   
   

C. 0.15 M Ba2+ ions and 0.30 M Cl- ions.   

D. 0.15 M Ba2+ ions and 0.15 M Cl- ions.   

E. none of the above   


Answer Key: C
Question 2 of 12    0.0/ 4.0 Points
Solubility of gases in water:

A. is independent of pressure above solution.   

B. decreases with increasing pressure above solution.   

C. increases with increasing pressure above solution.   

D. Gases are not soluble in water.   
   

E. none of the above   


Answer Key: C
Question 3 of 12    4.0/ 4.0 Points
How many moles of KOH are contained in 750. mL of 5.00 M KOH solution?

A. 56.1 mol   

B. 6.67 mol   
   

C. 3.75 mol   

D. 3.75 x 103 mol   

E. none of the above   


Answer Key: C
Question 4 of 12    4.0/ 4.0 Points
What is the molality of a solution made by dissolving 14.7 g of C6H12O6 into 150.0 mL of water? Assume the density of water is 1.00 g/mL.

A. 10.2   
   

B. 0.544   

C. 0.0816   

D. 0.980   

E. none of the above   


Answer Key: B
Question 5 of 12    0.0/ 4.0 Points
Which of the following compounds is a strong electrolyte?

A. C4H8O2   

B. C6H12O6   

C. C7H14O5   

D. NaC2H3O2   
   

E. all of the above   


Answer Key: D
Question 6 of 12    0.0/ 4.0 Points
Which of the following is NOT an acid-base conjugate pair?

A. H2CO3 and HCO3-   

B. NH4+ and NH3   

C. H2S and OH-   
   

D. H2O and OH-   

E. none of the above   


Answer Key: C
Question 7 of 12    0.0/ 4.0 Points
A neutralization reaction between an acid and sodium hydroxide formed water and the salt named sodium sulfate. What was the formula of the acid that was neutralized?

A. H2SO4   

B. Na2SO4   

C. H2S   
   

D. HCl   

E. none of the above   


Answer Key: A
Question 8 of 12    4.0/ 4.0 Points
What is the pH of a solution that has a H+ concentration equal to 1.7 x 10-5 M?

A. 0.22   

B. 5.20   

C. 10.20   
   

D. 4.77   

E. none of the above   


Answer Key: D
Question 9 of 12    4.0/ 4.0 Points
The Bronsted-Lowry definition of an acid is:
   

A. a proton donor.   

B. produces H+ in solution.   

C. a proton acceptor.   

D. produces OH- in solution.   

E. none of the above   


Answer Key: A
Question 10 of 12    4.0/ 4.0 Points
A 35.0 mL sample of 0.225 M HBr was titrated with 42.3 mL of KOH. What is the concentration of the KOH?

A. 0.272 M   

B. 0.157 M   
   

C. 0.186 M   

D. 0.303 M   

E. none of the above   


Answer Key: C
Question 11 of 12    3.0/ 5.0 Points
Define “indicator”

a chemical compound that is designed to change color or shape when exposed to certain substances.

Model Short Answer: An indicator is a weak, organic acid that is one color in an acidic environment and another color in a basic environment.


Please see the definition in your book.
Question 12 of 12    0.0/ 5.0 Points
A 5.00-mL sample of a phosphoric acid solution of unknown concentration is titrated with a 0.1221 M Sodium Hydroxide solution. A volume of 5.99 mL of the base was required to reach the endpoint. What is the concentration of the unknown acid solution? Write the neutralization reaction, balance it, name the products THEN Solve the problem above.



Model Short Answer:  H3PO4 +  3 NaOH ? 3 H2O +   Na3PO4