Science & Mathematics - 11 August 2007

2007-08-11 16:26:44 · 2 answers · asked by baby 2 in Other - Science

A solution is made by dissolving 7.50g of NaOH, which contains some impurities in water and making up the solution to 250cm^3 of the solution. If 25.0cm^3 of the solution is exactly neutralized by 14.0cm^3 of nitric acid of concentration 1.00mol/dm^3, calculate the percentage purity of the sodium hydroxide.

2007-08-11 16:24:17 · 3 answers · asked by Stormy Knight 1 in Chemistry

C: Celsius
1 How much heat is needed to raise the temp. of 90kg of water from 18c to 80c?
2 if a 1MJ of heat is transferred to 10kg of water initially at 15c what will its final temp be?
3 if 12kg of water cools from 100c down to room temp. (20c) how much heat will it release to the environment?
4. how much heat would be needed to warm 1.6kg of ice from -15c to its melting point of 0?
5. A 5kg lock of lead at 250c cools down to 20c. How much heat does it give off in doing so?
6. if you must do 500J of work to operate a pulley system, and the pulley system lifts a 50N load to a height of 3m, how efficient is the pulley system?
7. For every megajoule of chemical potential energy in the fuel used to run a certain truck only 120kJ of useful work is done by the truck in making itself move. How efficient is the truck? Where are some of the places that the energy from the fuel is wasted?

2007-08-11 16:24:12 · 2 answers · asked by Anonymous in Physics

what courses will one partake in other to become a medical doctor and how many years does it take to complete such course

2007-08-11 16:21:04 · 6 answers · asked by irene 1 in Medicine

hooked like a group of resistors except instead of a resitor holding the parallel position furthest from the terminal, a simple length of copper was in its place, completing a resistance free loop between the terminals for electricity to travle. Will less electricity travel through the resistors now as a result? Will no electricity travel?

e.g.


(+)(-)___
l^^^^^^^^l
l^^^^^^^^l
l^^^^^^^^l
l^^^^^^^^l
l______l

2007-08-11 16:19:55 · 6 answers · asked by kmm4864990 1 in Physics

SOLVE FOR J . NOT FOR K

2007-08-11 16:18:41 · 13 answers · asked by stayyoung 3 in Mathematics

Honeybees routinely build honeycombs, these possessing striking geometric features.

Honeycomb panels - especially Aluminum - are routinely used in Aerospace. They have an incredible strength-to-weight ratio.

Googling gave me little more. So, I wonder if there's a relationship between the honeycomb panels so often used in aircraft and the honeycombs built by bees. Thanks!

2007-08-11 16:12:43 · 2 answers · asked by Anonymous in Engineering

In my own opinion, I actually do think their is life outside of our galaxy. Post your own opinions. ^^

2007-08-11 16:10:29 · 9 answers · asked by hayabusa445 2 in Astronomy & Space

I was looking us ab exercises and I found out that the STOMACH VACUUM is address with this exercise?
Where is this bpdy part in the human body? What is it used for?

2007-08-11 16:10:02 · 2 answers · asked by Long Beach Guy 1 in Medicine

2007-08-11 16:00:41 · 8 answers · asked by Anonymous in Physics

2007-08-11 15:59:30 · 5 answers · asked by berry2rose 1 in Earth Sciences & Geology

If I had a DC brushless fan that requires 12vdc to operate, and realized this fan can produce electicity. Would it be possible to make an array of the same type of fan and let wind blowing on the array, power the lone fan for cooling? Is this possible?

2007-08-11 15:59:08 · 3 answers · asked by smittybo20 6 in Physics

hey, iam having a difficulty in solving this question:

the rate of decay of a radioactive substance is (km) where m is the mass of the substance remaining. Show that the half life (the time in which the amount of the original substance remaining is halved) of the substance is 1/k ln 2

2007-08-11 15:58:46 · 3 answers · asked by DeSeRT EaGLe 1 in Mathematics

addition, what is the best view spot if I live in the southern part of NJ? anyone?

2007-08-11 15:56:46 · 2 answers · asked by timetodeal168 1 in Astronomy & Space

what time will it be at tonight?

2007-08-11 15:55:46 · 9 answers · asked by blondewbrains93 1 in Astronomy & Space

1. keq for the reaction 2 h2o(g) > 2 H2(g) + O2(g) is 2.9 x 10^-82. What does the value of keq reveal about the reaction? Suppose a container holds 1.55 M H2o(g). 7.00 x 10^-23 M H2(g), and 4.72 x 10^-15 M O2(g), Is the system at equilibrium? If not, in what direction will he reaction proceed?


2. Given the equation OF2(g) + H2O(g) >< O2(g) + 2 HF(g) + 318 kJ. predict the direction of shift in the equilibrium position if (a) OF2 is added. (b) H2O is removed (c) pressure is increased, and (d) temperature is loered. In each case, briefly explain your answer.

2007-08-11 15:54:47 · 1 answers · asked by ashley t 1 in Chemistry

2007-08-11 15:39:18 · 3 answers · asked by jenkoleser 2 in Astronomy & Space

The other night, in the midst of Beijings polluted air, I caught a good glimpse of what I thought was a shooting star, or a meteor. It was orange, huge, and had brown, glitter-like sparks coming from it. I'm just curious as to what it actually was, from a scientific point of view.

2007-08-11 15:25:54 · 4 answers · asked by Lia 2 in Astronomy & Space

I've heard conflicting answers as to which water absorbs faster in bloodstream. When you drink water, which water absorbs into your bloodstream faster, lukewarm water or cold water? More times than not I hear it is cold water, but why? I would think it would be lukewarm, and if so, can anybody post why? Thanks.

2007-08-11 15:24:58 · 2 answers · asked by Anonymous in Biology

2007-08-11 15:23:48 · 0 answers · asked by TJ 1 in Medicine

2007-08-11 15:23:21 · 13 answers · asked by Anonymous in Geography

my dad wants to know and he wont stop asking!

best answer plus points to someone who answerss

2007-08-11 15:16:49 · 1 answers · asked by Anonymous in Astronomy & Space

Are there even kites in the NE of america, and are they even water birds in the first place? If so which ones.

Ive gone through all sorts of sea egals, gulls, really all the raptors i can think of. I just happened upon photo's of kites and the shape looked just like that. Its NOT AND OSPREY, i looked at all sorts of photos of them and its not that. It looks so much like a kite.

White belly, slender sea-bird like wings, about three or four foot span, i think a brownish-greyish feathers, NO flight feathers at the tips of the wings, its very clean and pointy.

ANY IDEAS?

This is the fourth time ive seen this thing.

Iam in upstate NY.

2007-08-11 15:14:58 · 5 answers · asked by amosunknown 7 in Zoology

2007-08-11 15:14:44 · 3 answers · asked by Dawn H 1 in Astronomy & Space

im curious....i live in the philippines and i want to know if i will be able to see the perseid meteor shower here....

2007-08-11 15:11:29 · 7 answers · asked by EgOcEnTriC 1 in Astronomy & Space

list the steps in plain english please!

2007-08-11 15:09:11 · 3 answers · asked by Anonymous in Medicine

2007-08-11 15:09:11 · 4 answers · asked by DoWHATiDO 3 in Mathematics

2007-08-11 15:07:57 · 3 answers · asked by bylosis j 1 in Medicine

Here is how: http://www.skyandtelescope.com/observing/home/8935687.html

2007-08-11 15:04:34 · 2 answers · asked by campbelp2002 7 in Astronomy & Space

What direction will the media shower be traveling in the sky? North, East, West or South?

2007-08-11 15:03:21 · 5 answers · asked by Lover Amy9 1 in Weather