Chemistry - September 2006

2006-09-04 19:44:39 · 2 answers · asked by noreen_qau 1

does precipitation work?

2006-09-04 19:21:02 · 2 answers · asked by Yawny 1

Very small crystals composed of 1000 to 100,000 atoms, called quantum dots, are being investigated for use in electronic devices.

(a) Calculate the mass in grams of a quantum dot consisting of 1.200 104 atoms of silicon.

(b) Assuming that the silicon in the dot has a density of 2.3 g/cm3, calculate its volume.

(c) Assuming that the dot has the shape of a cube, calculate the length of each edge of the cube.



help: aggradro's (sp?) number is 6.022 x 10^23

2006-09-04 19:17:38 · 2 answers · asked by cheezzznitz 5

Very small crystals composed of 1000 to 100,000 atoms, called quantum dots, are being investigated for use in electronic devices.

(a) Calculate the mass in grams of a quantum dot consisting of 1.200 104 atoms of silicon.

(b) Assuming that the silicon in the dot has a density of 2.3 g/cm3, calculate its volume.

(c) Assuming that the dot has the shape of a cube, calculate the length of each edge of the cube.



help: aggradro's (sp?) number is 6.022 x 10^23

2006-09-04 19:04:30 · 1 answers · asked by cheezzznitz 5

Aspirin, C9H8O4, is produced from salicylic acid, C7H6O3, and acetic anhydride, C4H6O3, as shown below.

C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2

(b) How much salicylic acid would be required if only 53% of the salicylic acid is converted to aspirin?

(c) What is the theoretical yield of aspirin if 159 kg of salicylic acid is allowed to react with 149 kg of acetic anhydride?

(d) If the situation described in part (c) produces 163 kg of aspirin, what is the percentage yield?

2006-09-04 18:53:15 · 1 answers · asked by cheezzznitz 5

I asked this question and did not get enough info to solve the problem. I am not asking for anyone to solve this ..but could I please have some order on how to set this problem up? This has had me stumped for the past week..any help would be greatly appreciated!

A certain paint has a density of 0.914 g/mL. You need to cover a wall that is 7.6 meters long and 2.74 meters wide with a layer of paint that is 0.13 mm thick. What volume of paint (in liters and gallons) is required? What is the mass (in grams and pounds) of the paint layer?

thanks!

2006-09-04 18:50:00 · 8 answers · asked by revolutiondefense 1

2006-09-04 18:36:24 · 4 answers · asked by cheezzznitz 5

2006-09-04 18:35:48 · 5 answers · asked by lucky 1

this is alkanes experiment

2006-09-04 18:12:41 · 1 answers · asked by amazing_sweet_angel 1

this is experiment is all about alkanes

2006-09-04 18:10:57 · 2 answers · asked by amazing_sweet_angel 1

this is Alkanes experiment

2006-09-04 18:08:58 · 1 answers · asked by amazing_sweet_angel 1

when we talk of total resistance in a circuit, is internal resistance also counted? can a circuit have both parallel and series connections?

2006-09-04 17:31:21 · 7 answers · asked by mugdha_coolgirl8 1

ok you have 0.1 M NaNO3

which has a greater osmolarity...

0.1 M NaCl or 0.1 M NaNO3?

and please explain in details.

2006-09-04 17:26:27 · 2 answers · asked by Anonymous

One of the steps in the commercial process for converting ammonia to nitric acid is the conversion of NH3 to NO.

4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g)

In a certain experiment, 4.70 g of NH3 reacts with 5.83 g of O2.

Which is the limiting reactant? The answer is O2

How many grams of NO form? The answer is 4.37

How many grams of the excess reactant remains after the limiting reactant is completely consumed? THIS IS MY QUESTION. 4 was my original answer, but my teacher said it was wrong.

2006-09-04 17:25:09 · 1 answers · asked by cheezzznitz 5

2006-09-04 17:17:03 · 1 answers · asked by appolo 1

The complete combustion of octane, C8H18, a component of gasoline, proceeds as is shown below.

2 C8H18(l) + 25 O2(g) 16 CO2(g) + 18 H2O(l)

(a) Octane has a density of 0.692 g/mL at 20°C. How many grams of O2 are required to burn 5.15 gal. of C8H18?

2006-09-04 17:10:56 · 4 answers · asked by cheezzznitz 5

meters,feet,centimeters

2006-09-04 17:08:26 · 4 answers · asked by appolo 1

i need help so if any one can awnser this question or tell me where i can find a pic of a highly magnafied atom plz awnser this!!!!

2006-09-04 17:06:49 · 4 answers · asked by saxbabe13 1

2006-09-04 16:06:36 · 8 answers · asked by niraj_bhindi 1

99% of the Carbon on Earth is of the isotope Carbon 12, which has a half life of 50,000 years. Since the Earth is 4.5 billion years old, why is there still so much of it left? Wouldn't there be just a small fraction of it left? This may sound like a dumb question, but I've always wondered. Also, what happens to it when it decays and becomes radioactive?

2006-09-04 15:51:25 · 4 answers · asked by Michael F 3

I just love the effects of Vinegar and Baking Soda, but I have gotten bored of it lately. What are some other interesting things similar to that?
(BTW: I already tried undesolving food coloring, I couldn't get it to work)

2006-09-04 15:50:47 · 6 answers · asked by TS2 3

0.0334 mol C, 0.1000 mol H, and 0.0167 mol O

i just dont get how to do this, please walk me through.

2006-09-04 15:49:42 · 3 answers · asked by cheezzznitz 5

"De-icing salt" is used to melt snow and ice on streets. The highway department of a small town is deciding whether to by NaCl or CaCl2 for the job. The town can obtain NaCl for $0.25/kg. What is the maximum the town should pay for CaCl2 to be cost effective?

2006-09-04 15:45:31 · 5 answers · asked by buttrefly007 1

i got 25.9
are my significant figures wrong?
teacher says its wrong. what is correct answer?

2006-09-04 15:40:24 · 5 answers · asked by cheezzznitz 5

I got 1.41
my teacher says its wrong. Wrong significant digits, or what?

2006-09-04 15:39:49 · 2 answers · asked by cheezzznitz 5

2006-09-04 14:50:46 · 0 answers · asked by jakebasketball88 1

2006-09-04 14:29:13 · 9 answers · asked by God'sPrincess 2

Let's say it's sugar water, can you evaporate it back?

2006-09-04 14:12:02 · 8 answers · asked by God'sPrincess 2

2006-09-04 13:31:00 · 5 answers · asked by heartstandstill7 1

if so, how can a H atom = 1 amu AND a proton = approx 1 amu AND a neutron = approx 1 amu
it just doesn't add up to me, maybe an H atom doesn't have a neutron, but I don't know.

2006-09-04 13:26:05 · 12 answers · asked by outbaksean 4