Science & Mathematics - 12 November 2007

Follow the description of the reaction below and answer the question following it:

In a dry cell battery the reaction that releases energy is: metallic zinc reacts with ammonium chloride to form zinc (II) chloride and ammonia (NH3) and Hydrogen gas.

a. Write a balanced equation for the reaction.

b. What is the ratio of number of moles of ammonia produced: number of moles of zinc consumed?

c. Calculate the mass of ammonia released when 32.84 g of Zinc are consumed

2007-11-12 20:03:44 · 4 answers · asked by Anonymous in Chemistry

2007-11-12 19:55:54 · 8 answers · asked by alojj 1 in Earth Sciences & Geology

2007-11-12 19:50:28 · 2 answers · asked by Anonymous in Medicine

I am in need for velocity laws (equations), please write it down for me.
Thanks in advance.

2007-11-12 19:46:45 · 5 answers · asked by momet j 1 in Physics

I need it badly, I used to search all-over the net. However, some sites said that it can produce electricity while some sites said that it has no capability.

2007-11-12 19:45:38 · 2 answers · asked by jayveelim1323 2 in Chemistry

I mean, my little brother can barely get a shot in before I plaster him. Shouldn't he be a higher evolved species than me?

2007-11-12 19:39:40 · 8 answers · asked by Henning Warble 2 in Biology

(1/3)t+(1/5)t= 1
solve for t
I will worship thee if thou hast the power to answer this..

2007-11-12 19:25:27 · 12 answers · asked by danielspectrum 2 in Mathematics

Will we be able to transfer solid objects from place "a" to place "b" via teleporter in the future?
What do you think?

2007-11-12 19:23:33 · 13 answers · asked by jeffrompas 2 in Other - Alternative

dont come up with solar system, galaxy, space etc...
need to know much more higher.

2007-11-12 19:17:10 · 13 answers · asked by Anonymous in Physics

1) What masses of Iron (III) Oxide and aluminum must be used to produce 15 g of iron? What is the maximum mass of aluminum oxide that could be produced?

Fe2O3 + 2AL ---> 2Fe + Al2O3

2) When aluminum burns in bromine, aluminum bromide is produced. In a certain experiment, 6.0 g of aluminum was reacted with an excess of bromine to yield 50.3g aluminum bromide. Calculate the theoretical yield and percentyield for this experiment.

Need explanation please!

2007-11-12 19:10:57 · 1 answers · asked by Someguy25 4 in Chemistry

Can viruses be grown in the laboratory on synthetic material? Explain.

2007-11-12 19:06:17 · 1 answers · asked by Eshild 1 in Botany

this software maybe usefull for translate physics books because when you translating you need to write physics caracters.

2007-11-12 19:04:03 · 2 answers · asked by salar_toti 1 in Physics

A Norman window has the shape of a rectangle surmounted by a semicircle. If the perimeter of the window is 39 ft, find the value of x so that the greatest possible amount of light is admitted. (Give your answer correct to two decimal places.)

2007-11-12 19:01:36 · 2 answers · asked by Anonymous in Mathematics

Formulas and applications.

2007-11-12 18:58:44 · 2 answers · asked by mark k. 1 in Mathematics

Could someone please tell me how many paracetamol tablets can a chemist legaly sell someone over the counter without a prescription at one time?

2007-11-12 18:49:44 · 7 answers · asked by spanner 1 in Medicine

Teleportation??..
Or maybe some special powers??..

what is your stand??

2007-11-12 18:48:50 · 4 answers · asked by Kirin Desuke 2 in Biology

Is this because they have no heat on or is it because the doors are left open, or do they have air conditioners on?
My guess is that the heat given off by that many people would make the building hot. Does anyone know why its cold in the buildings?

2007-11-12 18:45:07 · 7 answers · asked by TicToc.... 7 in Weather

I have seen some documentary on DSTV and would like to have vedio to replay

2007-11-12 18:44:46 · 6 answers · asked by vulindlela m 1 in Astronomy & Space

I live in CA, and I saw a sort of whitish & clear spider in my room. It had long skinny white & clear legs with sort of a brown-ish body. I'm scared to death of spiders!! So I'm just wondering if this is poisonous or something.... I've never seen anything like this in my life! Help please! lol I'm really really afraid of spiders....I'm scared I won't get any good sleep. :(

2007-11-12 18:33:33 · 18 answers · asked by jenn 1 in Zoology

1. The total volume of hydrogen gas needed to fill the Hindenburg was 2.00 x 10^8L at 1.00 atm and 25.0°C. How much energy was evolved when it burned?

2. What are the signs (positive or negative) of q (heat) and w (work) for the following exothermic process at P=1 atm and T=370K
H2O(g)-->H2O(l)

Then one problem using Hess' Law, I can't get it to work out correctly:

3. Using the following data, calculate the standard heat of formation of the compound ICl (g) in kJ/mol
Cl2(g) --> 2Cl(g) ∆H° = 242.3kJ
I2(g) --> 2I(g) ∆H° = 151.0kJ
ICl(g) --> I(g) + Cl(g) ∆H° = 211.3kJ
I2(s) --> I2(g) ∆H° = 62.8kJ

2007-11-12 18:26:59 · 1 answers · asked by S281 2 in Chemistry

2007-11-12 18:26:32 · 8 answers · asked by Myra G 5 in Medicine

Is there more than one planet, or is it always the same one?

2007-11-12 18:21:57 · 14 answers · asked by ****** 2 in Astronomy & Space

math formulas are constantly being used in the workforce,
what are some examples?
Which jobs are they used in? and how are they used?

2007-11-12 18:15:23 · 9 answers · asked by Sezza E 2 in Mathematics

2007-11-12 18:13:45 · 7 answers · asked by Monica H 1 in Mathematics

http://www.local6.com/news/14578641/detail.html

There is video and photos. people actually saw this as it happened. If people did in fact see it in person that would rule out video hoax. The video was checked after the witnesses watched it for almost an hour.
Strange stuff.

2007-11-12 18:08:49 · 18 answers · asked by Father Ted 5 in Parapsychology

I think most people can recall about a Malaysian Astronout hitching a ride on the Soyuz to ISS. The issue is that there's some comment going around the he's just a Space Traveller. Do you agree ?

2007-11-12 18:03:30 · 3 answers · asked by Machang man 1 in Astronomy & Space

Need 4 science project @school. Need a simple image, as it needs to be used in a childrens book

2007-11-12 17:49:02 · 7 answers · asked by Beth 2 in Astronomy & Space

help

2007-11-12 17:43:36 · 5 answers · asked by Coddle Stripes & Horse Shoe Rain 1 in Mathematics

Elemental ananalysis of a compound results in the following data
65.45 % C
5.49 % H
29.06 % O
4.13 g of the compound fills a 187.0 ml bottle with a pressure of 2455.8 mm Hg at a temperature of 21.4oC. What is the molecular formula of this compound ?

2007-11-12 17:38:57 · 2 answers · asked by starrynight4592 1 in Chemistry

2007-11-12 17:34:56 · 5 answers · asked by Anonymous in Physics