Concentration Definition and 550 Threads

Homework Statement If the ozone concentration in a particular sample of air were 25 dobson units, what sould this concentration be in: a)ppm b) %(v/v)Homework Equations 1 dob = 2.69*10^20 ozone molecules / m^2 http://en.wikipedia.org/wiki/OzoneThe Attempt at a Solution The question is asking...

I know what the formal definition of ph is, and I am comfortable with logarithms, anti-logs, and the laws of exponents. Still, I get confused doing actual calculations and would greatly appreciate your input on the following: Suppose something has a ph of 3.5-How do you calculate the hydrogen...

0? latitude and north, the CO2 concentration over time goes from rather soft to erratic. What is responsible for this? Also, what is the mechanism in which CO2 concentration drops and rises every year?

what is the defination for the following:stress concentration sensitivity, fracture load cycle, notch size factor?? pls help thanx

does anybody knows what is and how to find notch radians??any formula??

What are the cases for section 1 and 3?? this is a stress concentration factor of notched or fillet bars problem. From the picture,how can we choose whether it is t=tension,z=compression or b=bending?? http://files.filefront.com//;5410211;;/ and...

Hi, I need some help with a few problems. Thanks! (1) You have a pH Electrode that reports a voltage in mV, which is proportional to the hydrogen ion concentration in solution. You also have pH buffers at known pH of say 4, 7 and 10. What do you do to translate the mV reading into pH...

I am looking for a college with a nuclear concentration in physics. What are the top colleges to be looking at? Right now on my list is Reed College, and RPI. Thanks!

Sarah wants to mix 400 liters of a solution that is 57.5 iodine. She has two solutions available. One is 20% iodine and the other is 70% iodine. How many liters of both should Sarah use? Answer in the form: 20% = ?, 70% = ?

I was wondering if anyone knows how to measure concentration. I'm going to have a lab prac. where we design an experiment to investigate the effect of concentration in the rate of reaction of calcium carbonate and hydrochloric acid. I already know that increasing the concentration will...

does water/ or solid have concentration? does water/ or solid have concentration? Why do we just ignore the concentration of solid or solution solvent and replace it as one M? I always thought the reason is because the concentration of solid or water solvent does not change much so in...

my answer would be yes because, a concentration is the measure of how much of a given substance there is mixed with another substance, so aslong as the water is mixed with something elce you can measure the concentation of water right?

A 1.00L vessel contains at equilibrium 0.300 mol of N_2, 0.400 mol H_2 and 0.100 mol NH_3. If the temp is maintained constant, how many moles of H_2 must be introduced into the vessel in order to double the equilibrium concentration of NH_3 I said that if I let the change in conc. of H_2 be...

studying was not a problem for me and i don't hate studying,but recently there has been a problem which has cropped up, here it is What i find is the knowledge/information is quite distributed, for eg there is not a single good textbook which can satisfy me, and so therefore i tempt to plan to...

If you ingest a drug, is there a mathematical formula that models how much of the drug is left in the system?

This week Electrodynamics test, and last week QM test have really made my cup full. Instead of 100% on QM test I scored 80% because I missed one of the terms in a verry verry long equation (some variational problem with verry ugly hamiltonian in cylindrical coordinates) when I was rewriting it...

While waiting for my other post to be moved, I'm putting this question up again. 25.00 mL of .1857 M Ba(OH)2 reacts with 30.00mL of .2228M NiSO4. Find the concentration of all ions after the reaction assuming that final volume is the sum of the initial volumes. Ba(OH)2 + NiSO4 -> BaSO4 +...

Hello Im completely stuck on this question and don't know where to begin or what to do.. and help or guidance is appreciated: A voltaic cell at 25oC consists of Mn/Mn2+ and Cd/Cd2+ half-cells with an initial cell potential of +0.768 V. The [Mn2+] concentration is 0.500 M. Use the Nernst...

Please help, A 15.23mg sample of cocaine was cemically digested to convert its nitorgen to ammonia and then diluted to 100.00cm3. A 10.00cm3 of this solution was placed in a 50.00cm3 volumetric flask and treated with 5.0cm3 of phenol solution and 2.0cm3 of sodium hypochlorite solution. The...

:frown: I did an experiment on the effect of substrate concentration on the rate of a catalase. I was given 6% substrate concentration of hydrogen peroxide. We had to do 3 trials with different concentrations of the hydrogen peroxide but we had to dilute the peroxide ourselves in the second...

Ammonium carbamate (NH2COONH4) is found in the blood and urine of mammals. At a temperature of 442 K, Kc = 0.043 for the following equilibrium: NH2COONH4(s) <=> 2 NH3(g) + CO2(g). If 10.2 g of ammonium carbamate is introduced into a 0.500 L container, what is the total pressure inside the...

An anomalous concentration of QSOs around NGC 3079 by E.M. Burbidge, G. Burbidge, H.C. Arp and W.M. Napier - who else? Abstract: So allowing for the lensing pair there are 20 QSOs in the location, which represent around a one in a million chance. But are there not a million or so (indeed...

im having troubles with this the teacher wants us to find hte instantaneous rate of reaction at time 60 seconds , so i trace 60 s to the graph and make a point where it meets. Now i draw a tangent to this point. This is what gets me, how long should this tangent me, because i kow i have to get...

Why is the following true?: \left[H^+\right]\left[OH^-\right]=10^{-14} It seems like they would cancel out (equal 10-7 instead). Thanks for your help.

Hello! In my chemistry lab we did an experiment where the purpose was to find the estimated concentration of sugar in unknown solutions. We used 10 mL of each solution, and I determined the mass of the solution of each unknown. From there I calculated the density (mass over volume). Using that I...

Hello :blushing: I need help trying to figure this out: Patent blue V is a food coloring designed under the code E 131. Using a scales of blue tints, we hope to determine the molar concentration of patent blue in a solution used to color candy in a candy shop. We make a range of tints...

Hi I'm a newbie and i have a problem here that i cannot solve, or i don't know how to solve. Hope you experts can help me out! Here it is: A tank contains 10 kg of sodium hydroxide in 1000 litres of water. Water is continuosly added to the tank at a rate of 5 litres/min so that the mixture is...

Does the concentration of dNTP in the bottle's label specified the total concentration of the four nucleotides or only each of them? When it says in the protocol "each 200uM" does it mean that i have to add a concentration 4 fold (200uM * 4) of the bottle to get all the four different...

Hey there ppl! I am doing an Acid/Base Titration to investigate whether the concentration of citric acid lemon juice, change over a period of 5 days. So i kindda need some help in this experiment, cause we are not allowed to ask our teacher any help! The main purpose of this experiment is that...

Do you have any good protocols for measuring the concentration of RNA? The ones i have they seem to be very confused. Thanks.

a gas is x ppm by volume Liquids are mg/L but what about the gas?

A question for anyone that has the ability to answer: I understand the difference between Frenkel and Schottky defects, and I also know that in different crystal structures, which one is predominant is different. I was wondering, what dictates which defect is the dominant one? Thanks for...

FOr the light dependent reaction, In the textbook it says that the H+ concentration gradient across the thylakoid membrane is maintained by: 1) photolysis 2) transport of electrons from photosystem II along carriers 3) formation of NADPH. I can understand 1) and 3), but I have no idea...

H2(g) + I2(g) = 2HI at a temperature T If 1.40 mol H2 and 3.50 mol I2 are placed in a 1.00 L vessel, what is the equilibrium concentration of I2 in the gaseous mixture? The equilibrium constant is K = 49.7 x 10 10 HINT You can use the...

H2(g) + I2(g) = 2HI(g) T = 731K K = 49.0 If at equilibrium 0.171 mol H2 and 1.571 mol I2 are present in a 1.04 L vessel, what is the concentration of HI in the gaseous mixture in moles/liter ? Ok I tried doing this question by setting up a mole ratio first...

dear everybody! i am very confused about this area and hope that you can help me out of this. for example this protocol: 1. Add sufficient bovine gamma globulin to each of eight test tubes to give you a calibration curve. Suggested values are 0, 10, 20, 30, 60, 90, 120 and 150 µg/ul...

What mass of solute do you need to make 50 ml of a 20 g/L solution? \frac{20_g}{1000_{ml}}=\frac{x_{g}}{50_{ml}} 20 g/L = 1 g/50ml Answer: 1 g How many grams of solute are there in 300 g of .50% NaCl solution .50%=\frac{x_g}{300_{ml}} * 100 .005%=\frac{x_g}{300_{ml}} x=1.5 grams...

Having a little trouble tackling this one. "What is the concentration of a 500 ml solution if, when diluted to a volume of 2 Liters, its new concentration becomes 20 g/L?" Here what I did, all in ml. \frac{x}{500+1500} \frac{x}{2000}=\frac{20}{1000} \frac{20*2000}{1000}=40=x...

Is there by any way one can concentrate the DNA in a solution ?

Hello all I just need confirmation as to whether I am performing this problem correctly: How would you prepare 1.00 L of a 0.50 M solution of HCl from a 12M stock reagent? My solution: 1.00 L * (0.5 mol HCl/ L solution) = 0.5 mol HCl V * (12 mol HCl / L solution) = 0.5 mol HCl...

This is a place full to the brim with academics, so maybe you can help me out here. What do you do when you have work to do, but you just can't seem to get on with it? My concentration is terrible at times, and today is no exception unfortunately... Surely some of you have had this problem before?

How could i (mathematically) show what the concentration of IO3- in the following solution? 15mL of 0.20mol/L IO3- solution 5mL of water

can anone help me with these questions? a) How many moles of hydrogen peroxide react with each mole of permanganate in the titrationmoles of MnO4- per mole of H2O2 b) Calculate the concentration of hydrogen peroxide in the 10 mL aliquot, taken from the reaction if the titration with...

3 Fe (S) + 4 H2O (g) = Fe3O4 + 4 H2 (g) This equilibrium has a Kc of 4.6 @ 850 degree C. Determine the concentration of water vapor present at equilibrium if the reaction is initiated using 8.00 grams H2 and an excess of iron oxide, fe3O4, in a 16.0 liter container. This is what I...

could you check this? AB(g) → A(g) + B(g) Rate = k[AB]^2 k = 0.2L/mol∙S How long will it take for [AB] to reach 1/3 (one third) of its initial concentration of 1.50M? What is [AB] after 10.0 seconds? 2nd order overall reaction so: part A 1/[A] - 1/[A]o = (k)(t) 1/0.5 -...

Heya's Having some problems with the following question: Trimethylacetic acid C_4 H_{11} COOHis a weak monoprotic acid. When 0.0010 mol of Trimethylacetic acid was dissolved in 100mL of water, the concentration of trimethylacetic ion was found to be 3.0 \times 10^{ - 4} mol.L^{ - 1} a)...

Hello I really need help for working out the concentration of an acid / base. 1) How can we use a simple thermochemistry measurement and a density measurement, to find the concentration of an acid or alkali? (other than titration) 2) How do you devise an experiment to estimate the...

Calculate the mass of paradichlorobenzene (M=147.01g/mol) that should be added to 20.00 ml of cyclohexane (d = .779g/ml) to make a .05 molal solution. I did this problem but i don't know if i did it correctly. first i found the mass of cyclohexane by using m=dv. (.05moles solute/kg...

I am currently working on an investigation on the effects of varying enzyme concentration on the rate of hydrolysis of casein. I have looked on the internet to work out the maximum rate, but they all depnd on one variable - substrate concentration. I cannot find any mathematical expressions to...

Is the soft iron core the only known way of concentrating magnetism? I know that Halbach arrays create a sort of "monopole" by canceling the field on one side of the magnet but that, in my opinion, is not really concentration but rather asymmetrical field distortion. Afterall, the array doesn't...