Recent content by sdoug041

Ah that is a good point, it's starting to become a little clearer. So: (0.01 mg NO3- N/L) x (1 mol N / 14000 mg N) x (1 mol NO3- / 1 mol N) x (62000 mg NO3- / 1 mol NO3-) = 0.04 mg NO3-/L Am I understanding this concept correctly?

But a mg/L is a ppm, at least concerning aqueous solutions. there is 10^6 mg of water in a litre. I think I'm still missing something though. It can't be as easy as just looking at the given values...

But for every mole of NO3-, there is 1 mole of N... So is there no conversions to be made here? I can just simply look at the values and if they are less than 44.3, they don't exceed the limit?

The question: Nitrate concentrations exceeding 44.3 mg NO3-/L are a concern in drinking water due to the infant disease, methemoglobinemia. Nitrate concentrations near three rural wells were reported as 0.01 mg NO3- N/L, 1.3 mg NO3- N/L, and 20.0mg NO3- N/L. Do any of these three wells...

Homework Statement Two very large horizontal sheets are 4.25 cm apart and carry equal but opposite uniform surface charge densities of magnitude \sigma. You want to use these sheets to hold stationary in the region between them an oil droplet of mass 364 \mug that carries an excess of five...

Thanks guys I have solved the question!

Homework Statement A cylinder with a piston contains 0.250 moles of oxygen at 2.40 * 10^5 Pa and 355K. The oxygen may be treated as an ideal gas. The gas first expands isobarically to twice its original volume. It is then compressed isothermally back to its original volume, and finally it is...

Alright Well thanks guys I'm just going to assume my prof entered the wrong value for now.

But shouldn't I be yielding a value >100 if I use Q_{\text{water}}+Q_{\text{iron}}=0? You can't just know that it's going to be greater than 100 then add the additional term... Aren't you supposed to test that by using the equation to see if you get over 100? And then if you do you need to take...

Homework Statement You cool a 90.0 g slug of red-hot iron (temperature 745 C) by dropping it into an insulated cup of negligible mass containing 85.0 g of water at 20.0 C. Assume no heat exchange with the surroundings. What is the final temperature of the water? Homework Equations...

Homework Statement Rods of copper, brass, and steel are welded together to form a Y-shaped figure. The cross-sectional area of each rod is 2.00 cm^2. The free end of the copper rod is maintained at 100.0 degrees C, and the free ends of the brass and steel rods at 0.0 degrees C. Assume there is...

Ok so 0<=b2<=5 I've found 6 possible solutions for the equations :D Thanks a lot, Dick.

Ok I see. If b3 >= 0 , and say b3 was indeed 0, then b2 would have to be -3 to satisfy the equation. Does this mean b3 should be 3<=b3<=8, and 0<=b1<= 5?

But we have 3 unkowns in 2 equations :s

Thanks :). I think I got it now.