Chemistry - September 2007

how would the melting point of a substance be obtained if it sublimes before it melts?

2007-09-23 13:27:36 · 6 answers · asked by Anonymous

a) mixture, solution
b) solution, homogeneous
c) pure substance, homogeneous
d) mixture, heterogeneous
e) mechanical mixture, properties
f) particle, pure substance

2007-09-23 13:25:35 · 1 answers · asked by tlbff 1

If I get help for one of these, I'll understand the rest. I just get a little confused. Okay, here is the question:

How many molecules are in 3.4 moles of water?

I know how to set it up, I'm just not sure how to calculate it. Please, help! My grade depends on you!

2007-09-23 13:25:32 · 7 answers · asked by omgwtf 2

I am given two structures and asked to complete the acid base reaction. I'm not sure how to do this and it is hard to explain without the structures given. This is the best I could do. The 2nd one is supposed to be a hexagon with 3 double bonds. And please ignore the periods; I didn't know how else I could deal with the spacing. How do I change them to a base? I thought I was supposed to remove a hydrogen but that is not working. Can someone please help?? Thank you!

.......O
........||
....../....\
H3C OH

...... ____
.....//.........\\
................N
......\____/
.......------- ..<------(double bond)

2007-09-23 13:25:05 · 1 answers · asked by redblitz528 1

Title: Bean Bag Isotopes (Relative Abundance and Atomic Mass)

Purpose: “The purpose of this experiment is to investigate the mass properties and relative abundance of isotopes for the ‘bean bag’ element (symbol, Bg) and to calculate the atomic mass of this element.”

Procedure:
1. “Sort the atoms in the ‘bean bag’ element sample (Bg) into three isotope groups (1,2, and 3) according to the type of bean. (Assume that each type of bean represents a different isotope and that each bean represents a separate atom.) Place each isotope group into a separate weighing dish or small cup.”

2. “Count and record the number of Bg atoms in each isotope group.”

3. “Measure the total mass of Bg atoms belonging to each isotope group. Record each mass to the nearest 0.01 g in the data table. Note: Zero (tare) the balance with and empty weighing dish and record the mass. Do this for each group.”

Data:
“Bean Bag” Isotope - Number of Atoms - Total Mass of Atoms
1. Red 144 39.9 g
2. Black 40 7.67 g
3. White 10 2.56 g

Results:
“Bean Bag” Isotope - Average Mass - Percent Abundance
1. Red About: .2777 About: 74.2%
2. Black About: .19175 About: 20.62%
3. White About: .256 About: 5.15%

Conclusion:
?

2007-09-23 13:20:52 · 1 answers · asked by Anonymous

What mass of solid aluminum hydroxide can be produced when 50.0 mL of 0.200 M Al(NO3)3 is added to 200.0 mL of 0.100 M KOH?

Al(NO3)3 + KOH --------> Al(OH)3 + K(NO3)

So the limiting reagent is the .01 mols Al(NO3)3.

= (.01)(77.98 g/mol Al(OH)3)) = .7798 g

Is this correct?

2007-09-23 13:17:16 · 1 answers · asked by the Jam 2

NCCH2CH2CO2CH3

and

CH3OCH2CH2NHCH3

What are the functional groups and what should the be labeled? (names)

2007-09-23 11:20:46 · 1 answers · asked by Paulllll C 3

I know iodate is an oxyacid...but how am i suppose to know its 3 and not 2

2007-09-23 11:02:31 · 5 answers · asked by yasi 2

2007-09-23 11:00:48 · 5 answers · asked by xburned_icex 1

OK, lets see who gets this one~~~~~

What's the density of a block of marble that occupies 382 cm3 and has a mass of 759 g?

Answer in units of g=cm3.

2007-09-23 11:00:41 · 3 answers · asked by Anonymous

what is the formula for each of the following compounds

1 ammonium hydrogen phosphate

2 bromous acid

3 potassium hydrogen sulfide

4. calcium iodine

5. cesium perchlorate

2007-09-23 10:51:26 · 1 answers · asked by Anonymous

I'm trying to get a mental picture of these quantum numbers in a multielectron atom

Can someone tell me if this is correct ...this is what I imagine now ...but I don't know if it's right

_______________________________________________

above the nucleus ..there's shells determined by the principle quantum # n that extend to infinity

Then within each of these shells ...(I picture them as a transparent sphere ...but that's probably wrong) there's X number of electrons ....some have the same angular momentum going really fast, some are going slower around this shell ....

The ones with the same velocity are traveling around the same circumference of the shell .....and the ones with different angular momentum l numbers are going on a slightly different circumference so it looks like a cloud ...and then there's a max of 2 electrons who can have the same angular momentum in this shell ....
????

2007-09-23 10:42:34 · 1 answers · asked by Anonymous

Copper Sulfide is formed when copper and sulfur are heated together. In this reaction, 127g of copper reacts with 41g of sulfur. After the raction is complete, 9g of sulfur remains unreacted. What is the mass of copper sulfide formed?

2007-09-23 10:28:09 · 2 answers · asked by Anonymous

2007-09-23 10:25:06 · 4 answers · asked by Annoymous 1

please explain why or why not it isnt

2007-09-23 10:05:55 · 2 answers · asked by Anonymous

2007-09-23 10:00:21 · 9 answers · asked by alenailuy 1

23.5

0.046

then could you explain a little? thanks

2007-09-23 10:00:16 · 1 answers · asked by Anonymous

2007-09-23 09:41:30 · 5 answers · asked by pinkcolorhlk 2

The volume of the earth is 1,083.1579 x 10 to the ninth power kilometers cubed. How many liters is this? Please explain. I need help!!!

2007-09-23 09:40:22 · 5 answers · asked by Anonymous

The jewelers' mass unit for diamond is the
carat. By definition, 1 carat equals ex-
actly 200 mg.

What is the volume of a
4:28 carat diamond? The density of diamond
is 3:51 g=cm3. Answer in units of cm3.

2007-09-23 09:37:07 · 6 answers · asked by Anonymous

Cross system conversion
:[

2007-09-23 09:35:59 · 2 answers · asked by Redfoxmaddy 1

The formula of an acid is H2XO6. The mass of 102 molecules of the acid is 23,010 amu. What is the atomic weight of X?

2007-09-23 09:30:24 · 4 answers · asked by Anonymous

Tin metal and nitric acid...produtcs are a solid, a tin oxide and a brown gas, nitrogen oxide

2007-09-23 08:51:54 · 2 answers · asked by racer x 1

temperature on a hot summer's day: 10 degrees Celsuis? 20 degrees C? 30 degrees C?
Room temperature: 0 degrees degrees Celsius? 10 degrees C? 20 degrees C?

2007-09-23 08:39:07 · 3 answers · asked by lifeeeisgood 2

Elemental phosphorus occurs as tetratomic molecules, P4. What mass of chlorine gas is needed for complete reaction with 375 g phosphorus to form phosphorus pentachloride?

2007-09-23 08:36:09 · 3 answers · asked by neena m 1

2007-09-23 08:29:17 · 2 answers · asked by Anonymous

2007-09-23 08:27:42 · 2 answers · asked by Anonymous

There are 3.29 g of iodine-126 remaining in a sample originally containing 26.3 g of iodine-126. The half life of iodine-126 is 13 days. how old is the sample?

2007-09-23 08:16:35 · 7 answers · asked by sillylilchalupa 1

HNO3(aq) + H2O(l) -> ___(aq) + NO3-(aq)
What compound is needed to fill in the blank?

I have already tried H3O and H3O+ but the problem won't accept my answer

2007-09-23 08:06:50 · 2 answers · asked by beeboroachgoingon197 1

2007-09-23 07:46:11 · 1 answers · asked by 1Da 2