Chemistry (Science & Mathematics) - March 2007

The _______ molecules mixed with the solvent molecules in a solution cause the vapor pressure of a solution to be _________ than the vapor pressure of an equal volume of pure solvent.

2007-03-08 07:49:15 · 4 answers · asked by Tracey Lee ♥ 2

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HELP!!! Classify the following statements as true or false.?

1. One mole of CO2 has the same number of oxygen atoms as one mole of SO2

2. One mole of water has the same number of atoms as one mole of neon.

3. One mole of SO2 has more molecules than one mole of ozone O3.

4. One mole of SO2 has the same mass as one mole of CO2.

5.One mole of water has more molecules than one mole of carbon dioxide.

2007-03-08 07:43:57 · 4 answers · asked by Anonymous

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22 mg of a certain protein was dissolved in water to make a solution of 3.50 mL at 27C?

22 mg of a certain protein was dissolved in water to make a solution of 3.50 mL at 27C. If the osmotic pressure is 1.35 torr, what is the molecular mass of the protein?

To enter an answer in scientific notation use an e

6.022 x 1023 = 6.022e23

1.340 x 10-8 = 1.340e-8

Enter a numeric answer only, do not enter units.

2007-03-08 07:43:12 · 2 answers · asked by Anonymous

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How many moles of water are combined with each mole of PtCl4?

5.00g of a sample oh hydrated PtCl4 are heated and lose 1.50g of water.

2007-03-08 07:42:43 · 1 answers · asked by msnolan05 1

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How many grams of sulfur (S8) would have to be dissolved in 150.0 g of carbon?

How many grams of sulfur (S8) would have to be dissolved in 150.0 g of carbon tetrachloride to lower the freezing point by 1.50 degrees celsius?

kf = 29.8 K-kg/mol for CCl4

2007-03-08 07:42:26 · 3 answers · asked by Anonymous

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CHEM QUESTION...please help?

The freezing point of benzoic acid remains relatively constant throughtout the freezing process. Is the same is true for the freezing point of a solution?

what? can you explain this for to me PLEASE!?

2007-03-08 07:42:13 · 1 answers · asked by Tracey Lee ♥ 2

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An empirical Chem problem?

I have this problem...where a strip of copper is weighed then suspended in a test tube constaining idodine vapor generated by heating solid iodine. a white compound forms and uniformily coats the strip of copper then the compound + copper is weighed. Then it is washed off completely dried and weighed.
Data: mass of clean copper strip 1.2789g
mass of copper strip and compound 1.2748g
Mass of copper strip after washing 1.2748g

ok so here is my dilema so how would i determine # of moles of the iodine that reacted. I assume i take the difference of the clean Strip and divide by the molecular mass of product that should have formed i know it is copper iodide but is it CuI2 (2 is subscript) CuI and then i guess You figure out #moles of copper by the ratio? between Cu and I or I2 (i know its diatomic in beging but is it Copper (2) iodide or Copper iodide... then how would i figure out the emirical formula since its just the simplest ratio?

Thank you in advance

2007-03-08 07:40:30 · 2 answers · asked by nate 1

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Helium is dissolved in water with the total pressure of gas (Helium + water vapor) over the water being 1.60

Helium is dissolved in water with the total pressure of gas (Helium + water vapor) over the water being 1.60 atm. The temperature is 25o C. What is the concentration of Helium in the water?
Give your answer in g/L .
The vapor pressure of water at 25.0oC is 23.8 mm Hg.

Note that kH has units of mol/L / mmHg

2007-03-08 07:40:15 · 4 answers · asked by Anonymous

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what volume of hydrogen at STP is released when 8.25g Mg reacts?

Mg metal reacts with HCl to produce hydrogen gas:

Mg(s) + 2Hcl(ag)-----> MgCl2(ag) + H2 (g)

what volume of hydrogen at STP is released when 8.25g Mg reacts?

2007-03-08 07:36:55 · 2 answers · asked by Jacquline M 1

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Need Chem Help! ASAP!?

Disulfur dichloride, S2Cl2, can be made by treating molten sulfur with chlorine gas, according to the following unbalanced equation:
S8(l) + Cl2(g) ® S2Cl2(g)
How much S2Cl2 (in grams) can be produced if you start with 38.10 grams of sulfur, and 84.87 grams of chlorine gas?

2007-03-08 07:32:18 · 2 answers · asked by Anonymous

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can someone put these elements in order of reactivity: Mg Au Al Cu Sn Fe C?

2007-03-08 07:31:30 · 3 answers · asked by Anonymous

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How I can Demonstrate the atomic mass is approximately equal the number of protons + the number of neutrons ?

2007-03-08 07:07:49 · 4 answers · asked by aam a 1

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pressure temp ? lost.?

a scuba diver 40 ft below the ocean surface inhales 50.0 mL of compressed air in a scuba tank at a pressure of 3.00 atm and a temperature of 8 C. What is the pressure of air in the lungs if the gas expands to 150.0 mL at a body temp of 37 C?

2007-03-08 07:06:25 · 4 answers · asked by Jacquline M 1

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there is a mystery solute dissolved in water. it is a pure substance and the water is colored brown.?

how can i determine the substance?

2007-03-08 07:00:59 · 3 answers · asked by aznbrother123 1

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what color will nickel burn and what is the name for this property?

2007-03-08 06:45:07 · 1 answers · asked by aznbrother123 1

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gas chromatography mass spectrometry?

Is this a good test for alcohol in urine?

2007-03-08 06:24:26 · 4 answers · asked by kevinschlegelmilch 1

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need help understand how to do this chemistry problem?

a gas at a pressure of 2.0 atm is contained in a closed container. Indicate the changes in its volume when the pressure increases to 6.0 atm.

2007-03-08 06:16:11 · 7 answers · asked by Jacquline M 1

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Freezing point Question, please help??

The freezing-point of potassium ethanoate is greater than that of the other two solutes (urea & camphor) when an equal number of moles is used.

Could you please explain this to me?
THANKS ♥

2007-03-08 06:10:35 · 1 answers · asked by Tracey Lee ♥ 2

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what are the things calcium carbonate are used for making?

2007-03-08 06:08:00 · 9 answers · asked by bunnyere 1

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What is the concentration of Oxygen in the water?

Oxygen is dissolved in water with the total pressure of gas (Oxygen + water vapor) over the water being 2.00 atm.

The temperature is 25o C. What is the concentration of Oxygen in the water?

Give your answer in g/L .

The vapor pressure of water at 25.0oC is 23.8 mm Hg.

Note that kH has units of: (mol/L) / (mm Hg)

Enter a numeric answer only, do not include units in your answer

2007-03-08 06:02:22 · 3 answers · asked by silverlightning81 1

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