Science & Mathematics - 27 October 2007

Help math word problem urgent!?
Andy,Bob,Chris split $1,000 among them to be invested in diff. ways. each begins with a different amount of money!!!!! . at the end of the year they have a total of $1,500. bob and chris have both doubled their money, while andy has lost $100. what was andy's original portion?

2007-10-27 14:11:44 · 5 answers · asked by ~USA~ 2 in Mathematics

lead sulfide, in ores, can be assayed by the reaction:

2PbS + 6HNO3 (aq) + K2Cr2O7(aq)--> 2 S + 2PbCrO4(s)+ 4NO2(g) + 2KNO3(aq) + 3H2O

A 6.053 g sample of ore, treated with excess nitric acid and potassium dichromate yielded 6.094 g of lead (II) chromate. Calculate the percent by mass of lead sulfate in the ore.

if you know how to do this...can you show me your work. i did it and i ended up with 37.5 %. I don't know if I did this right...I think I did something wrong with the mole ratio. Thank you so much =]

2007-10-27 14:11:39 · 2 answers · asked by Save A Tree [Remove a Bush] 4 in Chemistry

2007-10-27 14:09:34 · 3 answers · asked by soccer_maniaco 1 in Chemistry

why did the crucible have to be covered during cooling

2007-10-27 14:09:09 · 3 answers · asked by 2010nurse 1 in Earth Sciences & Geology

I'm applying to university soon, however I can't decide on doing a bachelor of science vs. a bachelor of engineering. What are the pros and cons of each program?

2007-10-27 14:08:55 · 1 answers · asked by Anonymous in Other - Science

2007-10-27 14:08:37 · 6 answers · asked by Anonymous in Chemistry

2007-10-27 14:05:11 · 2 answers · asked by Shorty 1 in Chemistry

1. Technical grade.
2. Reagent grade is not important
3. Analytical reagent (AR) grade
4. General lab grade.

2007-10-27 14:04:15 · 2 answers · asked by Anonymous in Chemistry

I have looked at some of Euclid's proofs in his 13 books but can not find a proof.

2007-10-27 14:03:35 · 5 answers · asked by Anonymous in Mathematics

a.Ba(NO3)2 + NH2SO3H + H2O → Ba(NH2SO3)2 + HNO3
b. Ba(NO3)2 + NH2SO3H + H2O → BaSO4 + NH4NO3 + HNO3
c. Ba(NO3)2 + NH2SO3H + H2O → Ba(NH2)2 + H2SO4 + HNO3

2007-10-27 14:03:30 · 4 answers · asked by sam h 1 in Chemistry

2 sin x= -1

x | x = ? + 2pi(k)

and

x | x=?+2pi(k)

the answer must be an integer or fraction

2007-10-27 14:01:03 · 1 answers · asked by Anonymous in Mathematics

9 sin^2 Ɵ + 12 sin + 4 = 0

round to the nearest tenth

2007-10-27 13:58:30 · 2 answers · asked by Anonymous in Mathematics

2007-10-27 13:58:28 · 6 answers · asked by YA W 1 in Engineering

Some of the economic uses include industrial products and mining and their effect on tropical rainforests. Also whether rainforest's medicines will be there forever.

i'm having trouble finding information
Thanks if you can help.

2007-10-27 13:57:25 · 1 answers · asked by Anonymous in Botany

Given that f(x)= (x^2 – x)/x and g(x)= (2x+3)/(x – 1), find f(x) * g(x).

I need to write a test for my Pre-Calc midterm and just wanted to make sure this was correct.

the answer I got was 2x+3. is it right? show your work please ;]

2007-10-27 13:56:48 · 3 answers · asked by winniemazing 2 in Mathematics

needed for the balanced half-equation?

2007-10-27 13:56:30 · 2 answers · asked by Anonymous in Chemistry

why are nitrites and nitrates used in food processing? what is the concern over their use?

2007-10-27 13:55:51 · 4 answers · asked by Anonymous in Biology

2007-10-27 13:55:31 · 18 answers · asked by Anonymous in Paranormal Phenomena

If X and Y are positive, which of the follwing represent X percent of Y?
A) 0.01XY
B) 0.1XY
C) XY
D) 10XY
E) 100XY

2007-10-27 13:52:42 · 4 answers · asked by Anonymous in Mathematics

This is just a trivia question posted on a site I go to. I've been racking my brain for hours now and I can't come up with an answer because I don't think enough information is given. If it is solvable, any tips on how to do it... or the outright answer would be helpful :P

2007-10-27 13:51:53 · 5 answers · asked by ember_daya 2 in Mathematics

2007-10-27 13:51:07 · 11 answers · asked by Anonymous in Geography

what kind of bird am I?
The first person to tell me (and star me) gets the points!

2007-10-27 13:45:29 · 6 answers · asked by Anonymous in Zoology

I am doing a project on and element and i have chosen potassium. I am having trouble finding the following two things about it: Economic issues related to the element and environmental impacts of the element. If anyone knows where i can find this please let me know this would be very helpful...i've looked everywhere thanks!

2007-10-27 13:42:06 · 1 answers · asked by Anonymous in Chemistry

my sister is doing a science project for her 7th grade science class. she's set on doing a project on how a plant set horizontally on the counter will still grow vertically towards the sun. she only has a month to do the project-
what kind of plant would grow fast enough so there would be visible progress in a little less than a month?
Any ideas on how to improve this project are wonderful, too.

2007-10-27 13:38:28 · 9 answers · asked by wildoverdramatic 2 in Botany

A 45-year-old man was admitted to the hospital with chest and back pain. On examination, his chest was dull to percussion. A chest X-ray shows lower left lung inflitrates. A sputum culture reveals alpha-hemolytic, gram positive, catalase negative cocci that were inhibited by optochin. The bacteria produce acid from lactose. Identify the species of this bacterium.

2007-10-27 13:37:10 · 4 answers · asked by truckee 1 in Biology

Hello, I am trying to understand how to solve these problems. For the first one I don't know what to do and al of my answers come out wrong. I am not good with fractions. For the Second one, I just don't know what to do. So please could you help me by showing what you did so I could get a better understanding of what to do. Thanks.

1)5v over 6 + 7 over 6 = 1 over 12

2) 2(p-7.5)-4=32

2007-10-27 13:32:25 · 15 answers · asked by Anonymous in Mathematics

Who is correct, and if friend #2 is correct what is the correct answer.

2007-10-27 13:31:01 · 8 answers · asked by needs math help! 1 in Mathematics

When you change the answer's signs around in an equation, is there a name or property for that?

For example:

-5 - 11 - h = -7
here's where i'm confused: you circle and change the subtraction to addition with a negative, right?
-5 + -11 + -h = -7
-16 + -h = -7
+16 +16
the two 16s on the left are inverse, so they get crossed out, and you solve the other side, which leaves you with:
-h = 9
now are you allowed to just solve for a positive h, like this:
h = -9
or can you? i really have no clue!!!!

2007-10-27 13:30:44 · 5 answers · asked by =^..^= 2 in Mathematics

If an integer is divisible by 9, then the sum of its digits is divisible by 9. If the 7-digit integer 1,22X,333 is divisible by 9, what digit does X represent?

2007-10-27 13:28:06 · 4 answers · asked by utkarsh m 1 in Mathematics

Solve the Quadratic Equation using the Square Root Principle, Completing the Square, or the Quadratic Formula

(x – 5)^2 = 16
thankyou

2007-10-27 13:26:27 · 13 answers · asked by sumguy 1 in Mathematics