Chemistry - March 2007

"if 86.5 ml of 0.002 M NaOH are required to reach the equilibrium point determine the concentration of the benzoic acid if you started the titration with 15 ml of benzoic acid. What will be the pH?"

I find this hard but for NaOH moles I got 0.00173 mol NaOH. And for Benzoic acid at 15ml i got 0.015 mol Benzoic acid.

I am stuck. I need help and directions.

2007-03-10 12:42:18 · 3 answers · asked by avalentin911 2

2007-03-10 12:29:12 · 3 answers · asked by torinaishere 1

2007-03-10 12:23:39 · 4 answers · asked by J-dub 1

I am having yet another problem that I need help with. Thanks a lot

"A compound that would release ammonia gas when it is heated with aqueous sodium hydroxide and would give a precipitate with a 1:1 ion ratio when added to aqueous barium chloride. This chemical may be found in fertilizer such as Miracle Grow for Tomatoes.

The primary ingredients in the Miracle-Gro powder are as follows:

• 5.8% Ammoniacal Nitrogen
• 9.2% Urea Nitrogen
• 30% Available Phosphate
• 15% Soluble Potash
• 0.02% Boron
• 0.07% Copper
• 0.15% Iron
• 0.05% Manganese
• 0.005% Molybdenum
• 0.06% Zinc

Write the chemical formula and the name of the compound."

2007-03-10 12:02:13 · 3 answers · asked by Anonymous

I'm doing a chemistry project and I'd like to know the colour of representation for Magnesium and Oxygen Ion in a lattice structure when it forms compound MgO.

I do you that the universal colour of representation for oxygen is red. How about magnesium?

Do help me out!

2007-03-10 12:01:13 · 3 answers · asked by Anonymous

I would like to know how i can separate salt, sand and water so that i have three different containers holding salt, sand and water.

2007-03-10 11:55:11 · 19 answers · asked by Shakey_101 2

How do I calculate the relative molecular or relative formula masses of the following:
a) ethanol, C2H5OH
b) oxalic acid dehydrate, H2C2O4.2H2O
c) potassium dichrromate, K2Cr2O7
d) calcium hydroxide, Ca(OH)2
e) silver iodide, AgI

Note: I am asking for help on how to do these questions. What are the processes I must do to calculate these relative molecular or relative formula masses of the above examples? Thanks for helping. I don't mind you showing me how to do a couple of them completely if you don't mind. I'm having trouble with these ones. I do have a large chemistry book but I can't work these ones out. Thanks for helping me.

2007-03-10 11:52:10 · 4 answers · asked by Anonymous

1. The percentage by mass of hydrogen in calcium dihydrogenphosphate is given approximately by:

a) (1*2*100)/((40) + 2(1 + 31 + 64))

b) (1*2*2*100)/((40) + (4y1) + (2*31) + (8*16))

c) (1*2*2*100)/((12) + (4*1) + (2*31) + (8*16))

d) (1*2*100)/((40) + 2(2+ 31 +64))

e) (1*2*100)/((40) + (2*1) + 31 + 64

2. Which of the following is highest in mass?
a) 15.0 moles of helium, He
b) 5.0 moles of carbon, C
c) 2.0 moles of nitrogen monoxide, NO
d) 0.50 moles of yellow phosphorous, P4
e) 1.50moles of sodium hydroxide, NaOH

Thanks for helping me. For the 1st question I put a set of brackets for the whole numerator and a set of brackets for the denominators of the fractions. / means divide by. Thanks so much!

2007-03-10 11:46:48 · 3 answers · asked by Anonymous

2007-03-10 11:45:42 · 7 answers · asked by combat2463 1

2007-03-10 11:40:54 · 2 answers · asked by Anonymous

i bought a UV light and all over my walls in the bathroom and kitchen there is YELLOW. yellow stains dripping and stuff just coming down the walls ALL OVER.

i tryed cleaning it and it wont clean. without the UV light u cant even see it. what could this stuff be????

2007-03-10 11:40:10 · 1 answers · asked by seifer1237490 1

2007-03-10 11:35:24 · 8 answers · asked by ::) 1

2007-03-10 11:27:04 · 1 answers · asked by Anonymous

I have a 50% sodium hydroxide caustic. Is there a way to determine its molarity?

2007-03-10 10:59:41 · 4 answers · asked by Anonymous

If one were to combine 100 mL of 0.3 Molar BaCl2 solution and 150 mL of 0.4 Molar NaCl solution, what would the final molar concentration of chloride ions be in the resulting solution?

This was a problem on a chemistry test that I recently took. I am convinced the answer is 0.2 M, although my chemistry teacher tells me that it is 0.48 M. What do you think?

2007-03-10 10:56:44 · 6 answers · asked by Sir Drew M 2

which of the following statements are true?


a) For an acid H-A : the greater the electronegativity of A, the stronger the acid HA

b) For an acid H-A : the stronger the H-A bond, the stronger the acid H-A

c) HBr is a stronger acid than HF

d) H2SO3 is a weaker acid than H2SO4

e) HIO is a stronger acid than HBrO

f) For carboxylic acids : the smaller the electronegativities of the atoms in the group bonded to the carboxyl group, the stronger the acid


I Tried:
1. ACDEF
2. ADF
3. D

2007-03-10 10:38:48 · 4 answers · asked by Russell M 1

Calculate [ OH - ] of a 0.330 M solution of Pyridine C5H5N Kb = 1.70e-9

2007-03-10 10:37:23 · 1 answers · asked by Russell M 1

What is [ OH - ] for a solution where pH = 8.40?

2007-03-10 10:36:50 · 2 answers · asked by Russell M 1

what problems might result from using a tracer the contained a radioisotope that was either too stongly or too weakly radioactive?
also, scientict have been inserting tracer molecules containing phosphouse-32 into a population of bacteria to see where they store phosphorus. Which method might the scientist use to moniter the movement of tracers within the bacteria?

2007-03-10 10:36:48 · 2 answers · asked by ♥♥♥♥♥ 1

Cheryl dissolves an unknown gaseous substance in water and tests the solution for various properties. The results of her test are summarized below:

Test:
1. Use analog volt-ohm-meter (VOM) to check for electrical conductivity
2. Test for reaction with magnesium metal
3. Test solution with litmus paper

Results:
1. high electrical conductivity
2. vigorous exothermic reaction with Mg; hydrogen gas forms
3. blue litmus paper turns red

question:
Judging from the result of Cheryl's litmus test, is the solution acidic, basic, or neutral? Explain your answer.

2007-03-10 10:36:26 · 4 answers · asked by Anonymous

We are in the thermochemistry portion of class and I missed a lecture so Im a bit behind and don't know if Im solving this correctly.

Here is the question given: When 4.21 g of hydroxide are added to 250ml of water, the temperature rises 4.14(C). Assume that the density and specific heat of the dilute aqueous solutions are the same as those of H2O and calculate the molar heat of solution of potassium hyroxide.

Ok I think Im getting confused with the term "molar heat".

Do I basically use the q=MC(delta)T?

Add grams of water and grams of KOH together and solve for q?

Then divide the J I get into moles of KOH?

Or would I use q of solution=-q of reactants?

Please dont do it for me I just need a step in the right direction. Any help would be appreciated.

2007-03-10 10:32:47 · 3 answers · asked by MandyH 2

1) The pKa of vitamin c (ascorbic acid) is 4.17. Could we determine the amount if vitamin C in orange juice by acid-base titration? Why or why not?

2) Could we determine the amount of vitamin C in a vitamin C tablet by acid-base titration. Why or why not?

3) Based on the stoichiometry given in equations 1 and 2, what do you expect the titer value of a .01000 M KIO3 solution to be?
[ titer = mg ASCORBIC ACID / mL of KIO3 ]

2007-03-10 10:11:43 · 4 answers · asked by purple222 2

Thanks for looking. I ned help on a project. I need to know

Were calcium comes from?
What it reacts with?
How this element is used either as a elemt or compound? Something interesting about this element
Two traits asossed with the family it is in.

Thanks so MUCH! plz answer as many as you can. PLZ ANSWER though. Thanks!

2007-03-10 10:04:00 · 1 answers · asked by hi 1

I am working on a homework assignment, and I am completely lost on this question.

"A salt that breaks down to four ions per formula unit, imparts a yellow color when ignited by a Bunsen flame in the so called "flame test" and reacts with silver nitrate solution to give a precipitate that is soluble in both aqueous ammonia and nitric acid. This is an ingredient in Cascade dishwasher detergent.

Write the chemical formula and the name of the compound.

What common product(s) is the compound found in?

Use the following website as a reference: http://www.herc.org/library/msds/cascade...

Thanks very much for any help.

2007-03-10 09:47:05 · 3 answers · asked by Anonymous

when warmed in dilute sulfuric acid, 1-phenyl-1,2-propanediol undergoes dehydration and rearrangement to give 2-phenylpropanal.
why do we get at the end the 2-phenylpropanal and not the 1-phenyl-1-propanone?

explanation please,

thanx

2007-03-10 09:32:43 · 2 answers · asked by Anonymous

What is the difference between electronegativity and electron affinity?

My book says:
electron affinity: the ability of an atom to attact additional electrons
and electronegativity: the ability of an atom to attract a bonding pair of electrons to itself when bonded to another atom.

and i can see that obviously those are two different statements and that's the difference between them, but i don't understand the differerence.

thanks

2007-03-10 09:05:05 · 4 answers · asked by Anonymous

I have got a science study guide due on monday march 12. I have no idea how to do this

2007-03-10 09:00:40 · 7 answers · asked by Anonymous

how do you convert moles to grams . and grams to moles??
whats the formula??


i have a problem how do i solve it??

iron(IV) sulfide is burned in pure oxygen to yield iron(III) oxide and sulfur dioxide. if 0.012mol iron(III) oxide was produced, calculate the number of grams of iron (IV) sulfide used in the reaction.




little help please.. thanks..

2007-03-10 08:51:40 · 7 answers · asked by Anonymous

what is the molarity of an aqueious NaOH solution made with 5 kg of water and 3.6 mol NaOH (molar mass = 40.00)



How much methanol, CH3 OH (molar mass = 32.05 g/mol) is needed to make a .90 m solution in 250 g of water

2007-03-10 08:43:44 · 2 answers · asked by Anonymous

Describe how an understanding of chemical reactions has led to the development of new consumer products or technological processes.

PLease give example thanks

2007-03-10 08:37:12 · 1 answers · asked by 154 1