Science & Mathematics - 5 November 2007

A molecule that contains only carbon and hydrogen is composed of 74.83% carbon by mass.

a) What is the empirical formula?
b) How many hydrogen atoms are present in 25.8 g of this substance?

2007-11-05 13:58:02 · 3 answers · asked by bryon_barker 2 in Chemistry

7. (5 points) A computer is infected with a virus. Assume that it infects 20 other computers within 5 minutes; and that these PCs and servers each infect 20 more machines within another
five minutes, etc. How long until 100 million computers are infected?

2007-11-05 13:52:30 · 2 answers · asked by Hope C 1 in Mathematics

Just wondering.

2007-11-05 13:50:09 · 7 answers · asked by juicygirl729 1 in Paranormal Phenomena

A projectile is shot from the edge of a cliff h = 225 m above ground level with an initial speed of v0 = 105 m/s at an angle of 37.0° with the horizontal, as shown in Fig. 3-39.

I uploaded Figure 3-39 at this site: http://i20.tinypic.com/16c9oio.jpg

(a) Determine the time taken by the projectile to hit point P at ground level.
(b) Determine the range X of the projectile as measured from the base of the cliff.
(c) At the instant just before the projectile hits point P, find the horizontal and the vertical components of its velocity (take up and to the right as positive directions).
(horizontal component)
(vertical component)
(d) What is the the magnitude of the velocity?
(e) What is the angle made by the velocity vector with the horizontal (below the horizontal)?

Thanks soo much!!!!!!!!!!!!

2007-11-05 13:46:20 · 5 answers · asked by Bollywood Masti 4 in Physics

ok so i keep forgeting this....

well what is 5 1/2 in * 2 1/2in???
tell me how you did it

i know that 5*2=10 and 1/2*1/2= 0.25

but what is 5 1/2* 2 1/2?

2007-11-05 13:42:01 · 4 answers · asked by dominicandriver99 1 in Mathematics

Suppose a circle of radius r is inscribed in a hexagon. Find the area of the hexagon.

2007-11-05 13:41:48 · 7 answers · asked by Anonymous in Mathematics

Does anyone know what you can compare these to in a airport? It would really help! THANKS


cytoplasm
Nuclear membrane
Golgi Apparatus
Mitochondria
Chromosome
Cytoskelton
Ribosome
Vacuole

2007-11-05 13:41:21 · 3 answers · asked by Cheer28! 1 in Biology

How is it caused?
What are its effects or what will its effects be?

2007-11-05 13:41:04 · 8 answers · asked by Dark angel 1 in Earth Sciences & Geology

I can find the asymptotes no problem, but having trouble with the intercepts
G(x)= (x+2) / x^2+2x-3
G(x)= (x^2-3x-7) / (x+3)

2007-11-05 13:40:58 · 3 answers · asked by Anonymous in Mathematics

2007-11-05 13:40:45 · 5 answers · asked by Melvin :D 2 in Physics

i need help i tried like every site and it will not help me

2007-11-05 13:38:09 · 2 answers · asked by Anonymous in Physics

2007-11-05 13:36:53 · 3 answers · asked by Blaize D 2 in Mathematics

2007-11-05 13:33:59 · 2 answers · asked by Anonymous in Chemistry

Is it possible to get beyond the earth's gravitational field if you go far enough away from the earth?

a) Yes, you can get beyond the reach of the earth's gravity.

b) No, you cannot get beyond the reach of the earth's gravity.

2007-11-05 13:32:43 · 4 answers · asked by ? 6 in Physics

My friend said it is incorrect because something about viruses not being alive or something like that. Can someone give me an actual explanation?

2007-11-05 13:32:04 · 6 answers · asked by rykster22 1 in Biology

I can find the asymptotes no problem, but having trouble with the intercepts
G(x)= (x+2) / x^2+2x-3
G(x)= (x^2-3x-7) / (x+3)

2007-11-05 13:31:09 · 3 answers · asked by Anonymous in Mathematics

A workers pushes a 1.5 x 10^3 N crate with a horizontal force of 345 N a distance of 24.0 m The coefficient of kinetic force between the crate and the floor is 0.220.

a. How much work is done by the worker on the crate?
b. How much work is done by the floor on the crate?
c. What is the net work done on the crate?

A 0.075 kg ball in a kinetic sculpture is raised 1.32m above the ground by a motorized vertical conveyor belt. A constant frictional force of 0.350 N acts in the direction opposite the conveyor belt's motion. What is the net work done on the ball?

2007-11-05 13:30:16 · 2 answers · asked by redalert 2 in Physics

for every girl taking classes at the martial arts school, there are 3 boys who are taking classes at that school. If there are 236 students taking classes, write and solve a proportion to predict the number of boys taking classes at the school.

2007-11-05 13:27:31 · 7 answers · asked by JENNIFER C 1 in Mathematics

2007-11-05 13:24:25 · 3 answers · asked by Angel L 1 in Mathematics

Nitrogen and hydrogen gases react to form ammonia gas as follows:
N2(g) + 3H2(g) → 2NH3(g)
At a certain temperature and pressure, 4.07 L of N2 reacts with 12.2 L of H2. If all the N2 and H2 are consumed, what volume of NH3, at the same temperature and pressure, will be produced?

Ok so it gives me the liters and grams/moles and its not a limiting reaction. Do I use 273k at 1atm by chance?

And


The compound 1-iododecane is a nonvolatile liquid with a density of 1.20 g/mL. The density of mercury is 13.6 g/mL. What is the height of a barometer column based on 1-iododecane, when the atmospheric pressure is 769 torr?

I have worked several problems silimar to this but the question being in denisty screw me up. Do I some how convert the problem to mm Hg's since 760 mmhg=760 torr = 1 atm to find the height? I am guessing mm hg's.

I really apperciate your time guys. Answers has helped me so much in understanding in class.

2007-11-05 13:24:17 · 2 answers · asked by Reviction 1 in Chemistry

Please explain it in a layman's term.

2007-11-05 13:21:57 · 3 answers · asked by Perak Man 1 in Physics

I was walking down the corrider of my school one day and noticed that in the courtyard there was what i first thought to be a crow because of its colour but as i observed it i saw that it was indeed a pigeon. Is this common in pigeons? Could it be some sort of Crossbreed?

2007-11-05 13:17:45 · 2 answers · asked by cuyler a 3 in Zoology

2007-11-05 13:17:24 · 1 answers · asked by Anonymous in Physics

A 60.0 kg crate is attached to a weight by a cord that passes over a frictionless pulley. (1) If the coefficient of friction is 0.500, what weight will keep the crate moving up a 40 degrees incline at a constant speed? (2) If the cord is cut when the crate is at rest at the top of the incline, how far would the crate have slid by the time its speed reached 7.50 m/s?

Where do I even start? Can someone please explain this to me. I would be very, very thankful. Thanks.

2007-11-05 13:16:07 · 1 answers · asked by ☺♠JonasJay♫♦ 5 in Physics

I'm wondering whether I should buy a humidifier - I check weather.com and it'll report that the dew point is, for example, 43 degrees F and that the corresponding humidity is 67%. 67% seems pretty high (compared to an arid, desert environment). Is 67% relative? what is this a measure of exactly? Is there a better way to find out how much moisture is in the air? Thanks

2007-11-05 13:15:54 · 2 answers · asked by dontharshmymel 1 in Weather

ok i don't like to ask homework questions but i am somewhat stuck right now. I keep trying the problem but my answers are off. Here is the problem: Consider the dissolution of CaCl2:

CaCl2(s) ---> Ca^(2+) (aq) + 2Cl^(-1) (aq) deltaH = -81.5kJ

An 11.0g sample of CACl2 is dissolved in 125g of water, with both substances at 25.0°C. Calculate the final temperature of the solution assuming no heat lost to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/(°C*g).
If you could help me understand how to do this problem then i think i can figure out the rest. Thanks in advance

2007-11-05 13:14:50 · 1 answers · asked by live in the moment 2 in Chemistry

pls answer this.

2007-11-05 13:14:06 · 12 answers · asked by jE B 1 in Physics

I broke my boss's stirling engine display this morning. I need to replace it before he returns from his overseas trip by this Friday. To place an order online and wait for delivery takes too long. Anyone out there knows where I can walk in and buy a stirling engine model in Singapore or Hong Kong? Thank you!

2007-11-05 13:12:29 · 1 answers · asked by Anonymous in Engineering

2007-11-05 13:10:31 · 3 answers · asked by Lawliet E. 2 in Other - Science

2007-11-05 13:09:16 · 5 answers · asked by brian d 2 in Earth Sciences & Geology