Chemistry - October 2007

Sodium carbonate is a reagent that may be used to standardize acids. In such standardization, it was found that a 0.302 g sample of sodium carbonate required 25.4 mL of a sulfuric acid solution to reach the end point for the reaction:
Na2CO3 (aq) + N2SO4 (aq) --> H2O (l) + CO2 (g) + Na2SO4 (aq)
What is the molarity of the H2SO4? What is the normality of the H2SO4?

2007-10-28 12:08:22 · 1 answers · asked by Anonymous

Suppose your laboratory instructor inadvertently gave you a sample of KHP that was contaminated with NaCl to standardize your NaOH. How would this affect the normality you calculated for your NaOH solution?

2007-10-28 12:03:10 · 2 answers · asked by Anonymous

Also why is I(-) a better nucleophile than F(-) in protic solvents?

2007-10-28 11:17:11 · 1 answers · asked by Anonymous

explain what an element is and why the periodic table is so important

2007-10-28 11:15:07 · 2 answers · asked by Saran S 1

Determine the specific heat of a metal.

0.755 J/g°C

1.22 J/g°C

.887 J/g°C

.3820 J/g°C

2007-10-28 11:14:19 · 1 answers · asked by wtimm99 1

For the reaction, S2O3 (-2) + H2O -> HS ( -) + HSO3, please answer the following:
a) is this a redox reaction?
b) which species is reduced? (be very specific)
c) which species is oxidized? (be very specific)
d) which species is the oxidizing agent? (be very specific)

- Basically, can it be a redox reaction if the same thing is being oxidized and reduced? And if it is, wouldn't Sulfur be the answer for B, C, and D?

2007-10-28 11:13:31 · 1 answers · asked by Anonymous

2007-10-28 10:49:26 · 4 answers · asked by JitterBug589 3

why are there fewer electrons closer to the nucleus and more electrons farther away from the nuecleus?

2007-10-28 10:46:43 · 9 answers · asked by orangethursday20 1

2007-10-28 10:37:36 · 2 answers · asked by ori_culumn 1

What Volume of 0.750 M Na3PO4 is required to precipitate all the lead(II) ions from 130.0 mL of 0.250 M Pb(NO3)2?

2007-10-28 10:31:10 · 1 answers · asked by Anonymous

Sparingly soluble bases and salts, such as Fe(OH)2, and FeCO3 are more soluble in acidic than in neutral solutions. why?

can someone please help me answer this question?
thank you

2007-10-28 10:24:31 · 1 answers · asked by xyz 1

it's for a science project.

2007-10-28 10:22:27 · 1 answers · asked by queen_bernie 2

Chapter 5 is kicking my butt. I have a few questions that I just can't seem to figure out, can you please help. Thanks.

A compound of gallium with chlorine has a melting point of 77 C and a boiling point of 201 C. Is the compound ionic or covalent? What is a likely formula?

Assume that you were given samples of two white, crystalline compounds, one of them ionic and one covalent. Describe how you might tell which is which.

Is the planar triangular molecule boron (BCI3) polar? Explain.

Which of the following contains a coordinate covalent bond?
(a) H20 (b) HOClO (c) H30+

Molecular geometry (linear, planar triangular, bent w/one lone pair), tetrahedral, pyramidal, bent (w/2 lone pairs) for the following: CHCl3, H2S, O3, CS2, HNO2.

Thanks for any help you can provide.

2007-10-28 10:21:44 · 2 answers · asked by Anonymous

In general, when will a sparingly soluble salt precipitate from solution?

can someone please help me answer this question?
thank you

2007-10-28 10:21:37 · 1 answers · asked by xyz 1

I have this paper that asks me the family number of an element and the family name. How do I find out the family name?

2007-10-28 10:15:07 · 2 answers · asked by Coco M 1

2007-10-28 10:13:45 · 2 answers · asked by chaseslaws12 2

I would appreciate it if someone could answer it.

Again the question is:
Is there a consistent relationship between component masses and the formula of a compound? What is it?

2007-10-28 10:12:35 · 2 answers · asked by Anonymous

...what will be the atomic number and mass of the resulting element? Thanks.

2007-10-28 10:09:58 · 6 answers · asked by higherlovetx 5

calculate the number of moles of 5 mL of 0.004M AgNO3 and number of moles of CrO4^2- in 5mL of 0.0024M K2CrO4.

can someone please help me answer this question?
thank you

2007-10-28 10:07:47 · 7 answers · asked by abc 1

2Al2O3(s) → 4Al(s) + 3O2(g).

I think ΔH° is 3340 kJ/mol for 2Al2O3(s) but..

What confuses me is that since it is on the product side, I think it would be positive. The enthalpies for Al and O2 are both zero.

So... 0 - 3340 = -3340, or it is 3340 because its on the product side?

2007-10-28 10:07:08 · 2 answers · asked by Phobia 1

a piece of gold, mass 35.0 grams, absorbs 185 joules of heat energy when its temperature increases by 41 degrees C. What is the specific heat of gold?

2007-10-28 10:04:27 · 3 answers · asked by Chrishonda Alston 3

Considering which elements are being oxidized and reduced, determine how many moles of electrons are transferred between the elements being oxidized and reduced.

2007-10-28 09:53:44 · 3 answers · asked by Anonymous

also what does the period number of a row represent?

2007-10-28 09:48:09 · 8 answers · asked by trevor_mccurdy587 2

i am planning to hydrolyse glycerol triethanoate and then see how changing the concentration of the enzyme affects the rate of the reaction.
i am using the enzyme lipase.
what would be the best way to do this?
im not sure if i should use the method of saponification because then my catalyst would be NaOH as opposed to lipase.
there is also a titration involved in this which includes making a standard solution, but im not sure what my standard solution should be and why exactly i need to do a titration.
can someone please help me with this? ive somehow got myself REALLY confused!
thank you

2007-10-28 09:37:52 · 1 answers · asked by Anonymous

the principles with the proton-transfer reaction stuff are relatively simple but in certain equations how do you know what the base will be and what the acid will be?

like in this one water is the acid while ammonia is the base

NH3 (AQ) + H20 (L) ===> (BACK AND FORTH ARROW) NH4+ (AQ) + OH- (AQ)

Ok I get why they say that H20 is the acid, but if you weren't given the products, how would you know which one would transfer the proton and which one would accept it? cause otherwise i have no idea how to find the products. Thanks in advance.

2007-10-28 09:37:00 · 1 answers · asked by Anonymous

2007-10-28 09:34:18 · 1 answers · asked by max t 1

Calculate the moles of oxygen in the tank.

a) 383
b) 4.57
c) 0.0505
d) 0.383
e) 0.00378

thanks

2007-10-28 09:27:31 · 2 answers · asked by bocabrunette714 1

N2(g) + 3 H2 (g) --> 2NH3 (g) what is the maximum volume, in liters of NH3 that can be formed from 15.0 L of H2?

a) 7.50
b) 10.0
c) 15.0
d) 22.5
e) 30.0

2007-10-28 09:24:55 · 2 answers · asked by bocabrunette714 1

"Soft water" has been treated to replace the polyvalent metal cations with sodium and potassium ions. Why are the problems of scale and bathtub ring not associated with soft water?
...and/or...
What mineral(s) would be sources of the calcium in hard water?

2007-10-28 09:21:52 · 2 answers · asked by JitterBug589 3

17.78 mL of KMnO4 solution to oxidize all the Fe2+ ions to Fe3+ by the following reaction.

MnO4-(aq) + Fe2+(aq) Mn2+(aq) + Fe3+(aq) (unbalanced)

(a) What was the concentration of Fe2+ ions in the sample solution? in M

What volume of 0.0150 M K2Cr2O7 solution would it take to do the same titration? The reaction is shown below. in mL

Cr2O72-(aq) + Fe2+(aq) Cr3+(aq) + Fe3+(aq) (unbalanced)

2007-10-28 09:16:28 · 1 answers · asked by mark 2