Chemistry - April 2007

If 44g of a gas is found to have a volume of 24.5 L under a pressure of 50.66 kPa at 298 K, what is the molar mass of the gas?

I have three others like this and i dont know how to do them, please help me out here.

2007-04-30 14:59:10 · 1 answers · asked by Eddie G 1

A solution is 0.10 M AgNO3 and 0.10 M Ba(NO3)2. If solid Na2SO4 is added to the solution, what is [Ba2+] when Ag2SO4 begins to precipitate? (Ksp BaSO4 = 1.1 x 10^-10, Ag2SO4 = 1.1 x 10^-5)

The answer is: 1.0 x 10^-7 but I don't know how they got that. Please show how you would find that answer. Thanks!! :)

2007-04-30 14:49:13 · 1 answers · asked by 123haha 1

DATA TABLE

length of Mg ribbon--- .6cm
mass of Mg---.00828g
evidence of chemical reaction--- fizzy, white bubbles
volume of H2 gas---8.4 mL
corrected volume of H2 gas--- 8.2 mL
temperature of water bath--- 21.0C
barometric pressure--- 761.7 mm Hg


1. Calculate teh theoretical number of moles of hydrogen gas produced.


2. I understand this one.


3. Use the combined gas law to convert the measured volume of hydrogen to the volume the gas would occupy at STP.


4. Divide the volume of hydrogen gas at STP by the theoretical number of moles of hydrogen to calculate the molar volume of hydrogen.


5. What is the average value of the molar volume of hydrogen?


6. One mole of hydrogen gas has a mass of 2.02g. Use your value of hte molar volume of hydrogen to calculate the mass of one liter of hydrogen gas at STP. Thes is the density of hydrogen in g/L. How does this experimental value of the density compare with th

2007-04-30 14:48:58 · 2 answers · asked by LFL 3

A sample of gas at 0.830 atm and 25.0 celcius has a volume of 2.00L. What will its volume be at STP?

2007-04-30 14:43:23 · 5 answers · asked by pirateprincess 2

Will a plastic bottle of carbonated beverage (Coke, etc., blah blah) cool down faster in the fridge if it is no longer "factory fresh"?

In other words ('cause my brain pales in comparison to yours) will a highly pressurized bottle take more time to become cold when in the refrigerator than a bottle that has been opened?

Thanks ya'll!

2007-04-30 14:34:27 · 6 answers · asked by clever nickname 6

A radioactive isotope has an initial decay rate of 51.29 dps (disintegrations per second) for a sample. After an elapsed time of 7.86 days, the rate has decreased to 19.9 dps. What is the half-life (in days) of this isotope?


A Watt (W) is a unit of power equal to 1J/s. A kilowatt is 1000 watts. How many kilowatt hours (1000 watts/s for one hour) of energy would be produced by the complete conversion to energy of 0.62 mg of matter? Error tolerance: ±1%

2007-04-30 14:30:05 · 1 answers · asked by Anonymous

The question is:

only one of each of the following pairs of reactants undergoes a reaction. Complete and balance the equation for the reaction which occurs.
Co(OH)2 (s)+ NaOH (aq)-->
Al(OH)3 (s)+ NaOH (aq)-->

that was the only pair i couldnt get. i really think that the cobalt equation is the one that's right, but i'm not positive. Even if it is correct, i dont know what it would produce. I want to say just the cobalt ion and water and sodium...but then it cant be balanced. then, i want to just say it's cobalt ion and hydroxide, and Na. i'm just not sure..i'd like someone to verify it for me, please.

also, there's really no need to balance it for me, if you figure it out. i can do that on my own. :)

thank you!

2007-04-30 14:29:38 · 1 answers · asked by twim 4

In the following reaction between a weak acid and a strong base, which of the following is/are the spectator ion(s)?

2 HClO(aq) + Ca(OH)2(aq) --> Ca(ClO)2(aq) + 2 H2O(l)

BEST ANSWER TO FIRST CORRECT!!!

2007-04-30 14:26:16 · 2 answers · asked by Anonymous

Calculate the pH of a 0.35 M solution of KBrO (Ka of HBrO = 2.3 x 10^-9)

Please show how you get the answer. Thanks!!! :)

2007-04-30 14:16:48 · 2 answers · asked by 123haha 1

calculate the cost of productiion of lime
cost of raw material :
5lbs.4oz borax at $3.50
1lb guar gum at $5.95

2007-04-30 13:43:24 · 1 answers · asked by ngoc v 1

write a reactoin showing AL(oh)3 acting as a base toward H+ and as an acidd toward OH-

2007-04-30 13:28:40 · 2 answers · asked by Anonymous

a) Delta H is negative and Delta S is negative
b) Delta H is positive and Delta S is positive
c) Delta H is negative and Delta S is positive
d) Delta H is positive and Delta S is negative

If you could, please explain why you got the answer that you got.

2007-04-30 13:22:29 · 2 answers · asked by Anonymous

In the reversible reaction, the equilibrium shifts to the right because of all of the following factors except:

A. Adding heat
B. Adding reactant amounts
C. Formation of ammonia gas
D. Increasing pressure on reactants
E. Yielding an escaping gas


Please explain for me.

2007-04-30 13:13:06 · 2 answers · asked by chemistrychicka 1

A. In a first order gaseous reaction, if we decrease the volume of the container where the reaction is taking place, the velocity of the reaction will decrease.

B. A catalyst creates a new path for the reaction which requires a smaller activation energy.

C. Activation energy is constant for a certain reaction.

D. By increasing the temperature of a reaction, we increase the amount of molecules with sufficient energy to react.

E. All intermolecular collisions result in chemical reactions.

Please explain why its incorrect.

2007-04-30 13:10:26 · 2 answers · asked by chemistrychicka 1

2007-04-30 12:56:13 · 4 answers · asked by Anonymous

Given the following:

A --> 1/2B + C, K= 0.0334
3D --> B + 2C, K = 2.35

Calculate K for: 2A -> 3D

Here's my work..

I basically multiplied the first equation by 2 and flipped the second equation to get 2A -> 3D.

How would I calculate K now?

2007-04-30 12:52:58 · 2 answers · asked by Anonymous

so i missed a lab in grade 9 science because i went to Track.
anyways, i have to type up this lab and i have no clue about anything except that we had:

Lithium Nitrate
Sodium Nitrate
Potassium Nitrate
Barium Nitrate
Calcium Nitrate
Copper Nitrate
....and 2 unknown elements
to be exposed to a bunsen burner flame.

i know the colours produced by everything except the 2 unknown compounds. If you know what they might be (must be metal nitrates), please say so.

Also, i was given 4 questions:

1.what were the 2 unknown compounds and how did you decide what they were?

2. which metals were easy to identify?

3. Which metals were difficult to identify?

4. why were all of the compounds tested nitrates?

if you have any idea what the 2 unknown compunds were and any of the answers to the 4 questions could you please post!

2007-04-30 12:48:22 · 2 answers · asked by Franky Tank Runner 3

One liter of H2O aquires .57 KJ of energy when it goes over Niagra Falls. If all this energy is converted to heat, how much does the temperature of water rise?

Specific heat for water = 4.18 J/g.K

One Liter of H2O = 1 KG of water
K = Kelvin
J= Joules

2007-04-30 12:47:04 · 1 answers · asked by Abdul S 3

Is it true?

2007-04-30 12:35:00 · 2 answers · asked by green 1

2007-04-30 11:44:29 · 1 answers · asked by tony b 1

For 1.3 mole of the radioactive isotope chromium-51, half-life = 27.8 days, how many disintegrations have occurred after 18 minutes?

Enter a numeric answer only do not include units

Note: The answer is not 1.08e20

2007-04-30 11:36:58 · 1 answers · asked by Anonymous

Which of these are most polar (list them in increasing polarity)?

Ketone vs Carboxylic Acids vs Aldehydes vs Esters

Amines vs Amides

How would one figure out the relative level of polarity between these compounds?

How can I figure out whether the O=C ketone compounds are more/less polar than say for example, the O=C-OH carboxylic acids?

2007-04-30 11:05:50 · 2 answers · asked by Dave H 2

NaNO3------- NaNO2 + O2

2007-04-30 11:04:55 · 7 answers · asked by jere 1

I am the worst at chemistry and i was wondering if anyone could help me out w/ hw. I really do want to understand this so if u could explain how u did it that would be great.Thanks!!

68. Assign oxidation states for all atoms in each of the following compounds.

a. UO2 (charge is +2)
b. As2O3
C.NaBiO3
d. As4
e. HAsO2

2007-04-30 11:03:06 · 6 answers · asked by Glitter** 1

list your source(s) if possible please, thanks

2007-04-30 10:57:37 · 2 answers · asked by Anonymous

Please give details.

2007-04-30 10:49:26 · 2 answers · asked by Anonymous

With thermodynamics, one CANNOT determine...

a) the speed of a reaction
b) the direction of a reaction
c) the extent of a reaction
d) in which direction a reaction will be spontaneous
e) the temperature at which a reaction will be spontaneous.

I was thinking its either gotta be (a) or (c) but I can't make a decision.

2007-04-30 10:45:03 · 5 answers · asked by Anonymous

http://www.mp-docker.demon.co.uk/as_a2/topics/reactions_schemes_bromoethane/quiz_3.html

2007-04-30 10:44:32 · 1 answers · asked by Anonymous

MnO4(-) + H(+) + Fe(2+) ---> Mn(2+) + H2O + Fe3(+)

2007-04-30 10:41:18 · 1 answers · asked by AnDru N 2

A 12.45g aluminum metal strip is placed into an 2.3 x 10-1 mol/L solution of tin (II) bromide. If all the aluminum and tin (II) bromide react, what was the volume of the tin (II) bromide solution.

Balanced equation is this right?
Al2+ 2Sn2Br2 --> 2AlBr2+2Sn2
If not help?

2007-04-30 10:35:32 · 4 answers · asked by Anonymous