Chemistry (3rd time I've posted this)

Can someone check my answers? I've posted this a couple times and no one has responded. Is no one responding because they're all right or what?

1.) If you were involved in an acid rain monitoring project with several other samplers, why would it be important that all of you collect your samples on the same day and do the alkalinity tests within 24 hours?

Acid rain on another day may not have the same pH as the rain on that day. The pH may also decrease over time.

2.) A student did an alkalinity determination correctly, except that the sample titrated had a volume of 90.0 mL. Volume A was found to be 4.50 mL and Volume B was 7.00 mL.
a)Calculate the alkalinity value from these data and then calculate the correct value.
A=(2(4.50-7.00)=2.0 mL^-1
answer = 2.02mL^-1

b)What percent error would there be?

answer = .99%

c) Would there be an error in the classification of the stream? Explain concisely.

There would not have been an error in the classification. It was just a measurement error in this case.

3) EPA acidity tests can be performed by titrating a water sample to a pH of 8.2. What titrant in what concentration would you suggest for EPA acidity determinations?

The titrant I would suggest for EPA acidity determinations is sulfuric acid under a standard concentration.

And I've read it all three times. Sone of the questions I simply dn't uuderstand. For what it's worth, here goes.
1. I think your answer to #1 is poor. Probably everyone knows that the pH may/will change. Probably they also know that the pH will change over time. I think the question is asking, "WHY will the pH be different on different days and WHY will the pH decrease over time. You might address that the same amount of rain may differ on diffrerent days, that the rain front may have come from different loations of the world thus carrying different amounts of gases that causes the rain to be acid, etc. As to the alkalinity changing, WHY does it change; that is, WHY is it important to measure the alkalinity within a short time of sample collection. The answer is that the dissolved gases causing the rain to be acid have a vapor pressure and that over time they will slowly "evaporate" from the solution. Evaporate is not a good word but you can substitute a better one. You probably knew all of this but you need to spell it out, especially if this is for an assignment. If it's for general dissemination, it is even more vital to be specific.

2. I don't understand the volume A and volume B bit so I've skipped all of #2.

3. Again, I don't think you answer will cut it but it is a better answer than your #1. You were specific about using H2SO4 and that is good. I think the answer would be greatly imporoved if you specified the recommended concentration or give a range. To say "a standard concentration" will make the reader (your prof?) glance at the paper again and he/she may wonder if you know or if you are just evading the question.

I hope this helps a little although I couldn't answer all of the question.

And my addition. I have read it three times also, and ibid on DrBob's comments. It is confusing.
On the last, my thought is IF you are titrating an acid rain water sample you need a standard base sample (NaOH), especially if you want it to get to a pH of 8. However, it is not clear to me in number three what you are trying to titrate.
The clarity of your questions makes understanding very difficult. If you ask someone something three times, and they don't answer, it is quite likely they don't understand what you are talking about. If those folks are experts, and don't understand you, well, think about that. It is part of learning the art of communication.

  1. 👍 0
  2. 👎 0
  3. 👁 241
  1. I.d The others are right

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    1. Simplify. 3x^2+ 5x-5x^2-4x+5-2 A.-8x^2-9x+3 B.2x^2+x+3 C.-2x^2-9x+3*** D.-2x^2+x+3 2. Add or Subtract.(8x – 2y) + (3x – 4y) A.11x+8y B.4x-y C.11x-6y*** D.5x+2y 3.(5x^2-4x-1)-(-4x^2-4) A.-9x^2-8x-1 B.9x^2-4x+3*** C.x^2-4x-3

  2. @Cray

    I have removed the entire test you posted -- without any thoughts of your own, sad to say. If you wish to post the 4 or 5 that you absolutely cannot figure out after reading and re-reading your text, please do so, but be sure to

  3. Jiskha

    I typed several questions and answers regarding the subject of Geography, and suddenly, as I was waiting for a reply from Ms. Sue, it seemed as though my questions were deleted from the webpage where all of the other questions are

  4. Math HELP

    I have my answers at the bottom but please do these questions so I can check my answers. Check my answers as well. Subtract these fractions. !Reduce them! 1. 5/7 - 3/10= 2. 11/18 - 5/12= 3. 1/3 - 1/6= 4. 7/12 - 1/16= 5. 7/8 -

  1. Physics

    Please help me with the following problem: Joe is on a cross-country trip from New York to Los Angeles. He drives for 45.0 min at 70.0 km/h, 10.0 min at 95 km/h, and 30.0 min at 55.0 km/h, and he spends 20.0 min eating lunch and

  2. Programming

    The Romance World Cruise Line provides special gifts for passengers who are newlyweds, as well as for those who have been married more than 40 years. Design a pseudocode for a program that accepts a couple's last name, ship cabin

  3. Spanish-Please check SraJMcGin

    Hi, I redid some of the answers as suggested yesterday from someone who responded to my post. Could you please see if I did them correctly-Thank you- I made the corrections-someone yesterday redid a question but the questions

  4. To Troyer 0269

    I deleted your last science post, as I promised I would a couple of weeks ago. You posted five questions that I'm sure you could answer by reading your text. As you know, we don't give answers, but help students with problems they

  1. Science

    How do thermometers relate to the kinetic energy of particles of matter? Can someone please help quick I need help and I need the answer to be at least a couple of sentences I have no clue what the answer is but this is only the

  2. chemistry

    hi, Can you please double check to see if i have got this right? Is the empirical formual for oxide of arsenic As2O5? Cheers ;) Arsenic forms two oxides with oxygen. One is As2O5, the other is As2O3. I'm glad you posted today;



  4. English

    Now, let's check how well you can use the expressions you've learned. I will distribute handouts. You have to solve the problems. Are you finished? Then, I'll check the answers. Look at the answers on the blackboard. Check your

You can view more similar questions or ask a new question.