Science & Mathematics - 24 September 2007

Ok I need help with questions like this one, I have a test tomorrow, and I really need someone to help me understand it better.


8n -(n - 3)=9

the answer is n=6/7, but I need someone to explain. HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

2007-09-24 09:30:15 · 7 answers · asked by personalchefgurl 2 in Mathematics

Kc = .00463
T = 800 K
for the reaction:

COCl(sub. 2)(g) <=> CO(g) + Cl(sub. 2)(g)

Calculate the equilibrium partial pressure of all the components, starting with pure COCl(sub. 2) at 0.760 atm.

2007-09-24 09:30:01 · 1 answers · asked by Tiffany 4 in Chemistry

My piece of Aluminum foil has a mass of .19 g
Is this a conversion problem? I keep setting it up with Avogadro's Number, but it seems wrong to me.

2007-09-24 09:28:43 · 1 answers · asked by Ariana f 1 in Mathematics

2007-09-24 09:25:06 · 9 answers · asked by Nathan F 1 in Mathematics

element 1 but not 2? Express your answer in terms of k. Give an informal proof supporting your answer.

2007-09-24 09:24:41 · 2 answers · asked by simonkf2002 1 in Mathematics

So, I have an equation V=1/3h^(3r-h). The "^" signifies "squared" so it would be h-squared. Please solve for r and explain each step please. Thanks!

2007-09-24 09:24:34 · 4 answers · asked by =(Disullusioned_Dreams=( 1 in Mathematics

Physically what is it? Do we know? It is called a force, what use is that? What's it made of? If planets have it, how come they can make it? Do you need certain things or conditions to make gravity?

2007-09-24 09:22:41 · 11 answers · asked by Anonymous in Physics

From a socoilogists point of view please, and no stupid answers like: we evolved into humans and thought better.
thanks

2007-09-24 09:22:08 · 6 answers · asked by Anonymous in Zoology

How do I find the slope of a curve y=x^2-x-2 at x=a?

(btw this is having to do with tangent lines in calc)

2007-09-24 09:20:22 · 9 answers · asked by Samich 3 in Mathematics

2007-09-24 09:18:14 · 4 answers · asked by Anonymous in Mathematics

2007-09-24 09:14:43 · 8 answers · asked by Jennifer C 1 in Mathematics

I had a spine related injury, what kind of doctor do I need to go see?

2007-09-24 09:13:10 · 7 answers · asked by Anonymous in Medicine

a jetliner can fly 6.5 hours on a full load of fuel. Without any wind, it flies at a speed of 2.10 x 10^2 m/s. the plane is to make a round-trip by heading due west for a certain distance, turning around, and then heading due east for the return trip. during the whole flight, the plane encounter 55.0 m/s wind from the jet stream, which blows from west to east. what is the maximum distance that the plane can travel due west and just be able to return home?





A swimmer, capable of swimming at a speed of 1.3 m/s in still water (the swimmer can swim with a speed of 1.3 m/s relative to the water) starts to swim directly across a 2.2 km wide river. However the current is 0.91 m/s and it carries the swimmer downstream


a) how long does it take the swimmer to cross the river?


b) how far downstream will the swimmer be upon reaching the other

2007-09-24 09:12:57 · 1 answers · asked by Anonymous in Physics

2007-09-24 09:08:04 · 3 answers · asked by Sarah 1 in Mathematics

We did an experiment with magnesium verifying the law of conservation of mass. we weighed the crucible, then the crucible and the magnesium together, then a final time after heating the magnesium. We had to answer questions at the end and this one has me stumped. She asks:

If the formation of magnesium nitride is not taken into account and the gray residue after the initial heating is assumed to be wholly magnesium oxide, the experiment would take much less time. Explain what errors might result, i.e., would the mass of the MgO/ Mg3N2 residue be greater or less than the mass of pure MgO residue? How would this affect the final percentage yield?

my thoughts on this is that the residue would actually be less than the mass of pure MgO residue. the reasoning behind that is the weight of the MgO compared to the weight of the Mg3N2. if i had .5g of MgO residue it would be .0124mol. Compared to if i had 1/2 MgO and Mg3N2 i would have .00867mol of combined. what do you guys think?

2007-09-24 09:05:02 · 1 answers · asked by john s 3 in Chemistry

Worldwatch Report: Oceans in Peril
September 21, 2007


Our planet's oceans are in deep, deep peril, says a new report from the Worldwatch Institute. The only road to recovery may be to declare 40 percent of the world's oceans off-limits to human exploitation to ensure the restoration of life in depleted areas.
Seventy percent of the Earth's surface is covered by ocean, and three-quarters of the population live in coastal areas. We are all dependent on marine resources - yet our oceans are facing threats that include overfishing, toxic pollution, climate change and whaling.
A new report from the prestigious Worldwatch Institute, Oceans in Peril: Protecting Marine Biodiversity, calls for these marine reserves - areas where all extractive and destructive activities, including fishing are prohibited - while giving an alarming snapshot of the shocking state of the world's oceans. It's a wake-up call that should jolt the complacency of policy makers worldwide.

Written for the Worldwatch Institute by a team of experts - Greenpeace's Science Unit in the UK's Exeter University - Oceans in Peril updates an earlier study by the same team in 1998. They have been staggered by the scale and rate of destruction that has taken place in less than a decade in every ocean on Earth.


©Greenpeace/Grace Sharks entangled in a Japanese driftnet


The Science Unit provides crucial scientific expertise to our campaigns, and has a long history of working on oceans issues, including whaling, toxic pollution, climate change and overfishing.

"Recent studies such as the one which shows how 90 percent of the world's large predatory fish, which include the sharks, swordfish and tuna, have disappeared due to overfishing since the 1950s have helped expose what has been happening under the waves and have therefore been out of sight and out of mind to most people", says Paul Johnston, Greenpeace's chief scientist.

Oceans in Peril details new and emerging threats, such the increasing acidification of the world's oceans, and underscores how the race for ever-diminishing resources is forcing marine ecosystems to the point of collapse.

The report illustrates how 76 percent of the world's fish stocks are fully or overexploited, an estimate borne out by figures from the United Nations Food and Agriculture Organization (FAO), which suggest that 158 million tons of fish were harvested worldwide in 2005 - a seven-fold increase since 1950. Catch records between 1950 and 2000 show the "collapse" of 366 out 1,519 fisheries worldwide, most famously the Grand Banks cod fishery off Newfoundland.


©Greenpeace/Grace Orange Roughy and bycatch in the Tasman Sea

Oceans in Peril also details the pitfalls of fish farming, the supposed magic bullet of marine resources with alarming statistics: producing carnivorous animals such as salmon or marine shrimp requires 2.5 as much fishmeal as the amount of saleable fish eventually produced. For tuna caught in the wild and fattened in "ranches", the weight of fish fed to the tuna is a shocking 20 times more than what is actually produced.

The damage to thousands of marine animals and entire ecosystems by longlining and bottom trawling, as well as overfishing off the coast of developing countries, is made even worse by the estimated 20 percent of the global catch that is illegal, unregulated or unreported. This illegal catch is worth somewhere between $4-9 billion a year. While countries with enough resources to control their own waters stand some chance of putting measures in place to protect resources, there's little or no regulation of any kind of marine harvesting in international waters - an issue that needs to be urgently addressed at an international level.


500-year old Gorgonian Coral trawled from the sea bottom by a fish net. (Image ©Ministry of Fisheries NZ)

But it's not all doom and gloom - there is a beam of sunshine in the report, including a comprehensive package of measures that if implemented could reverse current trends, restoring the former productivity of our planet's oceans. That solution is the establishment of comprehensive marine reserves all over the world, protecting vulnerable species and habitats, enhancing fisheries beyond the reserve boundaries, and buffering the worst impacts of climate change.

Marine reserves are the single most powerful tool available for arresting and reversing the decline of our oceans and are equally applicable to the high seas as they are to coastal waters. The oceans have immense powers of regeneration and wherever in the world marine reserves have been established marine life is flourishing.

2007-09-24 09:02:02 · 5 answers · asked by yahyouknow 2 in Biology

Earth is represented on a map of a portion of the solar system so that its surface is the circle with equation x^2+y2+8x-10y-3323=0. A weather satellite circles 0.1 unit above Earth with the center of its circular orbit at the center of the Earth. Find the equation for the orbit of the satellite on this map.
I completed the square and tried adding the extra .1 on the end of the radius but I can't get hte right answer!! Any help?

2007-09-24 08:59:09 · 1 answers · asked by Jims Jennifer <3 2 in Astronomy & Space

2007-09-24 08:58:34 · 2 answers · asked by flower 1 in Chemistry

what sea are the west indies located?

2007-09-24 08:56:38 · 4 answers · asked by Anonymous in Geography

Whats the connection between the number of rays and the number of angles?? If there are 3 rays how many angles ETC???

2007-09-24 08:56:08 · 1 answers · asked by Girl 1 in Mathematics

I bought a 150 dollar TI-89 for calculus and over the summer the batteries leaked. I took them out and removed as much of the acid as possible with paper towels. Is there anything I can do to remove the majority of acid? The calculator is not working because the acid is still on the current connectors.

Thanks

2007-09-24 08:55:42 · 4 answers · asked by James D 1 in Chemistry

why can't you put your hand through a solid?

2007-09-24 08:50:41 · 4 answers · asked by London92 1 in Chemistry

2007-09-24 08:48:28 · 7 answers · asked by Anonymous in Astronomy & Space

The element with an electronic configuration of:
(1s)2 (2s)2 (2p)5 would be?

Boron, Carbon, Nitogen, Oxygen, Fluorine?

2007-09-24 08:44:09 · 2 answers · asked by Moose 2 in Chemistry

When we find that a badger, for example, eats fruits and grubs alongside small mammals, does this mean it is a case of either or, or would the creature die if its diet was unbalanced?

2007-09-24 08:41:44 · 4 answers · asked by Z 1 in Zoology

Can someone please explain how to do this question. I cannot remember how to do this for 2 unknown percents.

An element consists of two isotopes of mass 6.2882 and 7.9032 amu. If the average atomic mass of the element is 7.432 amu, calculate the percent abundance of the first isotope.

2007-09-24 08:40:48 · 1 answers · asked by AlfredoFernandez 2 in Chemistry

please explain to me thanks

2007-09-24 08:40:29 · 1 answers · asked by Anonymous in Chemistry

2007-09-24 08:34:22 · 7 answers · asked by Anonymous in Astronomy & Space

please make the answer simple, thanks.

2007-09-24 08:33:16 · 7 answers · asked by kiarathehotbabe 1 in Weather

Four point charges have the same magnitude of 3.3 x 10^-12 C and are fixed to the corners of a square that is 7.2 cm on a side. Three of the charges are positive and one is negative. Determine the magnitude of the net electric field that exists at the center of the square.

2007-09-24 08:33:14 · 1 answers · asked by Anonymous in Physics