Science & Mathematics - 29 January 2007

How many milliliters of .7M BaCl2 are needed to completely react with 280 ml of 0.5 M (NH4)2 CO3 ?

2007-01-29 18:39:32 · 1 answers · asked by Anonymous in Chemistry

2007-01-29 18:37:41 · 1 answers · asked by HeLP2007 1 in Botany

2007-01-29 18:35:01 · 13 answers · asked by Heather H 2 in Astronomy & Space

both a read leading to a bridge and the bridge must be replaced. the engineer estimates that it will take 20 days for the road crew to tear up and clear the road and an additional 60 days for the same road crew to dismantle and clear the bridge. the rate for clearing the road is 1.2 feet per day faster than the rate for clearing the bridge and the total distance is 124 feet. find the rate for clearing the road and the rate for clearing the bridge

2007-01-29 18:30:03 · 3 answers · asked by Inlove 3 in Mathematics

I always wondered if a space ship traveled in the same direction would there be an end to space? Everything we know has a beginning and and end. So what is the end of the universe like?

2007-01-29 18:29:40 · 8 answers · asked by Anonymous in Astronomy & Space

2007-01-29 18:28:47 · 12 answers · asked by sonal6195 2 in Botany

2007-01-29 18:28:13 · 17 answers · asked by Janu 4 in Astronomy & Space

Recently I got some really intriguing evidence which proves that it's all fake!

2007-01-29 18:27:56 · 11 answers · asked by mistress s~ 2 in Astronomy & Space

2007-01-29 18:27:11 · 2 answers · asked by Anonymous in Chemistry

A rectangle is 5 cm longer than it is wide. If the length and width are increased by 2cm each, the area is increased by 50 cm^2. Find the area of the original rectangle.

And explain how you did it please?

2007-01-29 18:26:43 · 5 answers · asked by Anonymous in Mathematics

2007-01-29 18:26:34 · 5 answers · asked by fereal 1 in Earth Sciences & Geology

2007-01-29 18:25:19 · 23 answers · asked by loquitataco 1 in Physics

Just trying to figure out why I can't find any power supplies (wall warts) that deliver the appropriate voltage? For example went to goodwill looking for a ps that would deliver around 5V and 500 mA, found a couple that said 4.2V or something like that. Got home and checked with Vmeter and found out it was like 7V. Is this just because there is no load on it or what? I'm somewhat new at electronics just trying to figure this out, don't want to have to add a regulator to my project. Thanks in advance.

2007-01-29 18:23:39 · 2 answers · asked by FastEddie 5 in Engineering

Im stuck with this prelab problem and I dont know what to do any help? or suggestions of what should I do ? Thanks

a.400 g sample of ascorbic acid is titrated with .10 M KIO3. The solution contains 5 ml of 1 M hcl and 1 g of KI(s). the iodate ion reacts with iodite I- , and H + to produce iodine and water.

IO3- +5 i- + 6H+ ---> 3 i2 + 3H2O
the ascorbic acid reacts immediately with the i2

when all the ascorbic acid has reacted an increase in the concentration of I2 and the reaction of I2 with I- to produce I3- signals the blue end point. triiodine I3- complexes with starch to produce the dark navy blue color.

I2 + I - -----> I3-

what volume of .10 M KIO3 is required to reach the end point.?

2007-01-29 18:20:59 · 1 answers · asked by Anonymous in Chemistry

2007-01-29 18:20:44 · 4 answers · asked by taniya g 1 in Engineering

2007-01-29 18:17:00 · 5 answers · asked by HeLP2007 1 in Botany

2007-01-29 18:14:57 · 20 answers · asked by Anonymous in Astronomy & Space

2007-01-29 18:14:56 · 6 answers · asked by Pierre-Denis J 1 in Biology

A ball is thrown vertically upwards with an initial velocity of 20.08 m/s. How long is the ball in the air? t= 4.09 s

What is the greatest height reache dby the ball? x= 20.6 m

**** Calculate the time at which the ascending ball reached a height of 15 m. ???

I'm stuck on the last problem. I tried plugging it into a qudratic equation 15m=0+20.08t + 1/2(9.8)t^2 so 4.9t^2 + 20.08t - 15. The answer was 0.64 s but it didnt' work and doesn't make since. I also trie comparing the two numbers so [2.049 s (the time it takes to reach the maximum height) * 15m/20.57m) = 1.5 s. That made more since to me, but this also didn't work. Any hints?

2007-01-29 18:13:28 · 4 answers · asked by Anonymous in Mathematics

2007-01-29 18:10:32 · 3 answers · asked by bel 1 in Medicine

2007-01-29 18:08:10 · 4 answers · asked by Anonymous in Biology

2007-01-29 18:07:52 · 9 answers · asked by tall aussie 1 in Weather

i need help im doing something wrong but i don't know what please help me

ok so here is the problem:

-2x + 8y = 14
-2x + 2y = -26

ok so what i did is subtracted since the both have the same sign

and came up with: 6y = 40

and if i Divide each side by 6y i will come up with 6.666666667

which tells me i did some thing wrong

y can't equal 6.666666667


So now what??????

please explain thanks =)

2007-01-29 18:07:15 · 12 answers · asked by Anonymous in Mathematics

2007-01-29 18:03:51 · 3 answers · asked by Anonymous in Biology

Ron ran the first part of the distance with a constant speed of 20 km/h and the second part, 15 km/h. It took him 10 minutes less to run the first part than the second part. The second part was 5 km shorted than the first part. Find the total distance.

Can you explain how you did it?

2007-01-29 18:00:59 · 6 answers · asked by Anonymous in Mathematics

this is what I got. 2-(3x-8)= 2-(3x+-8)
= 2+(-3x+ -8)
= -x +-6

2007-01-29 17:58:44 · 14 answers · asked by nikki 1 in Mathematics

2007-01-29 17:57:30 · 8 answers · asked by Anonymous in Zoology

can everybody tell me that what is the function of vacuole?
must be correct and please don't anyhow answered my question!thanks!

2007-01-29 17:55:30 · 1 answers · asked by hana 1 in Botany

I read a lot, heard a lot about pepole talking about fresh water is going to scare resource in future ? there will be politics, war all for the fresh water.
can somebody tell will this happen and why ?
and if yes, by what time or year it happen ?
its not possible to predict the time but if things keep on going this way, One country that is U.S. keep consuming the natural resources and keep contributing in pollution and global warming at current pace, how far is that situation from today.

2007-01-29 17:51:26 · 7 answers · asked by Anonymous in Earth Sciences & Geology

2007-01-29 17:48:00 · 13 answers · asked by Anonymous in Biology