Thursday

April 24, 2014

April 24, 2014

Total # Posts: 227

**Chemistry**

What is [H3O+] in a solution obtained by dissolving 215 mL HCl(g), measured at 23 degrees C and 757 mmHg, in 4.30 L of aqueous solution?

**Chemistry**

can u tell me what your final answer is? I got 7.96 * 10 ^5 ml.

**Chemistry**

thnx

**Chemistry**

How many millimeters of this solution should be diluted with water to produce 650 mL of a solution with pH= 11.50? 6.8% ammonia (d= 0.97g/ml)

**Chemistry**

I thought for the density, the calculation would be as follows: 0.15gKOH/g---> 1g of solution, density=1.14 g/ml.......0.15g/(1g/1.14g/ml) to get 0.171 g/ml. and then I thought molarity for [OH^-] was 2.51 * 10^-3. The proper set up I got like 3.66 g/? mL. I might be wrong!...

**Chemistry**

How many millimeters of a 15.0%, by mass solution of KOH(aq)(d = 1.14 g/ml ) are required to produce 26.0 L of a solution with pH = 11.40?

**Chemistry university level**

what mass of ethylene glycol, the main component, of antifreeze, must be added to 10.0 L water to produce a solution for use in a car's radiator that freezes at -23.3 degree C? Assume the density for water is exactly 1 g/ml.

**chemistry**

what is the lewis dot structure for SO4 -2 and the ideal bonds, mollecular structure and hybrid orbitals?

**Organic Chemistry**

i am not able to get the proper name but i can tell the structure i.e. ch3 ch3-ch2-ch2oso3

**chemistry**

the wander walls force of attraction increases,it become more stable and it requires less energy.

**Chemistry...Please Help**

GK, why don't you write the concentration of water for (e)?

**Statistics**

The percentage of adults who have been told at some point that they have hyptertension is 23.53%. If 10 adults are randomly selected, what is the probability that at least 8 have been told that they have hypertension?

**Chemistry**

Draw the Lewis structures for BrO3- and ClO4- and indicate their correct number of additional resonance structures. I'm a little confused about this. For example, I've got the correct original form of BrO3- down. Where all 3 O atoms are single bonded to Br, and the Br ...

**history**

I need information on Bull Capital Rampurva Maurya 323. thank you

**Chemistry**

Can someone please explain to me whats the difference between a buffered and non-buffered solution?

**Chemistry**

Yes I know it will be m=1. But what if I have something like log (base 1/4) 0.33 = m Then how would I solve something like that.

**Chemistry**

I haven't calculus in a while. So can someone please help me with this, its for rates: log (base 1/4) 0.25 = m I know that m = 1, but how would I solve for it using the log method.

**Chemistry**

I need help distinguishing between nucleophiles and electrophiles. Like one of the examples I am given shows methanal, chloroethane, and methanamine. Now it says methanal is electrophilic because the carbonyl group is polar since the more electronegative oxygen atom has a grea...

**Chemistry**

I understand why PCl3 is zero order, but I don't get why Cl2 is second order.

**Chemistry**

In the reaction PCl3 + Cl2 ---> PCl5. If the rate doesn't increase when the concentration of PCl3 is doubled and the rate increases by a factor of four when the concentration of Cl2 is doubled, how would I write the rate law for the reaction?

**Chemistry**

If I2 reacted with hexane, how would we know, which carbons the Is go on? Would only one of the iodine go to the hexane and the other form HI, or would they both join and H2 is a by-product?

**Chemistry**

Sorry, I meant hexane and not toulene. For hexane, I would expect a reaction to occur, but the colour stayed dark purplish. Would HI form here?

**Chemistry**

For a lab, I had to react toulene with 1% I2 in dichloromethane. Would HI form as a result of this? Logically, I think there would be no reaction because toulene looks too stable. But a colour change occured. Why would this happen?

**Chemistry**

Nevermind.

**Chemistry**

Given the weight of phenacetin and its percentage yield...how would I calculate its melting point?

**Chemistry**

Write the structure for the alkane: molecular mass = 72 u; forms four monochlorination products. Well since its 72u and its an alkane, I figured out that the formula is C5H12. But what does it mean that it "forms 4 monochlorination products"?

**Chemistry**

If I am given a molecular hydrocarbon structure, how would I be able to tell how sp3 hybridized carbons it possesses? Like my current question asks How many sp3-hydridized carbon atoms does 11-cis-retinal possess?

**Antiderivatives**

I can't figure this one out, the antiderivative of x^-1. I thought it would be c, but the derivative of c is zero.

**Math**

4/5 - 1/2 Find a common denominator and solve.

**Chemistry**

Thanks, for the help, although the last one doesn't look right, I understand it now. Thank You.

**Chemistry**

Can someone explain for organic chemistry naming, when something would be given something like "iso" in it or when we would say "s-butyl" or "t-propyl" etc., with "s" meaning secondary and "t" meaning tertiary.

**Chemistry**

How can I tell whether something is a weak, strong, or non-electrolyte? I know non-electrolytes do not ionize, strong almost completely ionize and weak only partially. But how would I be able to tell? Like, something like KOH is a strong electrolyte because it can ionize into ...

**Chemistry**

In a thermochemistry experiment the reaction of 0.0857 g of an unknown metal and an excess of 4.0 M HCl resulted in a 0.210 mL decrease in the volume of an ice/water mixture. Calculate the enthalpy of this reaction per 1 g of metal reacted. Needed data: density of water at 273...

**Chemistry**

The reaction between 0.055 g of calcium with an excess of water was carried out in an ice calorimeter. The volume of water in the calorimeter decreased by 0.20 mL during the reaction. Calculate the enthalpy of the reaction (in kJ/mol).

**Chemistry**

Oh, alrite so then heres what I get. 2 Cl(g) --> Cl2(g) exo-on H2O(l) --> H2O(g) endo-by 2 H2(g) + O2(g) --> 2 H2O(l) exo-on 2 Li(s) + H2O(l) --> 2 LiOH(aq) + H2(g) endo-by 3 NaN3(s) --> Na3N(s) + 4 N2(g)endo-by

**Chemistry**

When given a chemical reaction, how would I know whether a reaction is endo or exothermic and whether work is done on the system or by the system. Without using any calculations. So I have a couple reactions which I have to use chemical reasoning to to determine. 2 Cl(g) -->...

**Chemistry**

You have to determine the molar mass of CaCO3, by getting the molar mass of Ca and the molar mass of C, and the molar mass of O multiplied by 3 (since there are 3 oxygen atoms). You would get 100.087 g/mol. You would then do the mass/molar mass. 30.6/100.87 = your answer

**Chemistry**

How did you get 1 cal/g*c....is that a calculated constant or is manual conversion required? The answer I get using your method is 96.4kg, which is correct.

**Chemistry**

Wait, I did it wrong. q = mH(Tf - Ti) m = q/H(Tf-Ti) m = 675/[4.18x7] m = 23.06 But its still the wrong answer.

**Chemistry**

m = q/[(H)(Tf-Ti)] m = (4.18)[(675)(37-30)] m = 8.84 x 10^-4 I'm pretty sure this is wrong.

**Chemistry**

A person falls in water at 0 degrees C. After 20 minutes of exposure, they are suffering acute hypothermia, as their core body temperature has dropped to 30.0 degrees C. Assume that a person’s heat capacity can be approximated by the heat capacity of water, 4.18 J/g/oC. T...

**Chemistry**

So for ii) If HClO2 is the stronger base, then does that mean that ClO2 is also the stronger base?

**Chemistry**

Sorry, for iii) I meant that I think Cl3CCOO- is the stronger base.

**Chemistry**

For each of the pairs of bases below, choose the stronger base: (i) NH2- or NH3 (ii) ClO3- or ClO2- (iii) Cl3CCOO- or Cl2HCCOO- For i) I think it is NH2-, because it has a stronger ability to attract an H+ atom to become de-ionized. For ii) I don't know how to determine it...

**Chemistry**

Do I have to make equations and see which one forms a precipitate again? I don't think its H2CO3 or HCl because that would not minimize the effect of acid rain. So its either the 2 bases or CCl4. CCl4 + SO2 ==> CO2 + SCl4 ClOH + SO2 ==> CO2 + SOH Ca(OH)2 + SO2 ==>...

**Chemistry**

Stelco has been recently legislated to reduce total SO2 emissions from iron smelting operations. Select the most effective chemical reagent to desulfurize Stelco’s gas emissions as a strategy to minimize the environmental impact of acid rain in eastern Canada and why? CCl...

**Chemistry - DrBob222**

Alright. Thank you so much for the help today.

**Chemistry - DrBob222**

About these: NaCl + Zn No reaction CaCl2 + NaOH No reaction CaCl2 + Zn No reaction CaCl2 + Na2SO4 No reaction How would these give no reaction. NaCl + Zn ==> ZnCl + Na CaCl2 + NaOH ==> Ca(OH)2 + NaCl CaCl2 + Zn ==> ZnCl + Ca CaCl2 + Na2SO4 ==> CaSO4 + Na

**Chemistry - DrBob222**

Wait, AgNO3 with any unknown with Cl present would form a precipatate. So I can use that to tell between HNO3 and HCl. So now is the whole thing correct?

**Chemistry - DrBob222**

Alright, I've made a list of reactions that would produce precipatations. NaCl + Zn CaCl2 + NaOH CaCl2 + Zn CaCl2 + Na2SO4 CuSO4 + NaOH CuSO4 + Zn NaOH + AgNO3 NaOH + Zn BaOH2 + AgNO3 BaOH2 + Zn BaOH2 + Na2SO4 So this way I can figure if it is NaCl, CaCl2, CuSO4, NaOH,Ba(O...

**Chemistry**

I posted before about designing a procedure to determine two unknowns (1 solid, 1 solution). The possible solutions were: NaCl, CaCl2, CuSO4, NaOH,Ba(OH)2, HCl, HNO3, or H2O. The reagents given are: NaOH, HCl, AgNO3, Zn metal, Na2SO4, and H2O. The procedure I've designed s...

**Calculus**

f(x) = x(x^2 + 1)^(1/2) f'(x) = (x)(1/2)(x^2+1)^(-1/2)(2x) + (1)(x^2+1)^(1/2) f'(x) = (x^2)(x^2+1)^(-1/2) + (x^2+1)^(1/2)

**Chemistry**

Oh thanks. But can you tell me what this means "quantify the amount of solute in the solution".

**Chemistry**

I have to do lab experiment where I design a procedure to determine the identity of two unknowns given to me. One will be a solid and one will be a solution. I also have to quantify the amount of solute in the solution. The possible solids it could be are NaCl, KNO3, KHP, Zn, ...

**math**

This is probably really easy to work out: x^2=(x-2)(x+3) ^meaning to the power of I've got to: x^2=x^2+x-6 Don't know what to do next

**math**

Solve the following equations giving any roots in terms of pi in the .......? interval -2pi ≤ 0 ≤ 2pi. a) 2cos²Θ + sin²Θ = 0 b) 2cos²Θ + sin²Θ = 1 c) 2cos²Θ + sin²Θ = 2

**Chemistry**

Copper dissolves in nitric acid, producing copper (ll) nitrate. After reaction with sodium hydroxide and heating, copper nitrate changes to copper (ll) oxide. Calculate the percent yield of this process if 1.235 g of copper produced 1.452 g of copper oxide.

**Physics**

Mars' moon Phobos has a mass of 1.07x1016 kg and a mean radius of 11.1 km. Let's say our rocket blasts off from the surface of Phobos when Phobos is 9500 km from the surface of Mars. Does the rocket have to work harder to escape from the gravitational pull of Phobos or...

**science**

to find the vertical velocity we use 40*cos(30)=34.6 m/s W= KE = 1/2 mv^2 =1/2*0.15*34.6^2= 89.797 J or 90 J

**algebra**

70 = (75+63+68+x)/4 ...with x being what he must get. So you solve that: 70(4)-75-63-68 = x x = 74 So therefore, Sam must get a 74 or above to get a C grade. x => 74

**Physics**

Oh nvm, you mean F = 1/d^2 Got it...thanks.

**Physics**

but what is the 3^2 for? If the 3 is for the distance being tripled...what about the exponent 2?

**Physics**

If the distance between two objects is tripled, by what factor will the gravitational force between them change?

**Chemistry**

A sample of solid monoprotic acid with molar mass equal to 137.9 g/mol was titrated with 0.1879 M sodium hydroxide solution. Calculate the mass in grams of acid to be used if the volume of NaOH to be used is 25 mL.

**Chemistry**

If 1.000 kcal of heat is added to 1.700 L of oxygen in a cylinder at constant pressure of 1.00 atm, the volume increases to 2.100 L. Calculate the total energy change for this process.

**Science**

At what latitude (on Earth) is the elevation of the South Celestial Pole greatest?

**Trigonometry**

is that supposed to be zero or theta? if its theta: 1) theta = 23.6 2) theta = 53.1

**Math**

Find all values of x in the interval [0, 2 pi] that satisfy 2 cos x-1 = 0. cos x = 1/2 x = 60 How do I find the other value of x?

**Chemistry**

That means that AgNO3 is the limiting reactant as it has 0.0033 moles compared to 0.0039 for silver nitrate. But I don't get the last part you said. What same number of moles of silver bromate would I get? Do you mean same number of moles as the limiting reactant? Meaning ...

**Chemistry**

0.658 g of potassium bromate and 0.562 g of silver nitrate are added to 388 mL water. Solid silver bromate is formed, dried, and weighed. What is the mass, in g, of the precipitated silver bromate? Assume silver bromate is completely insoluble. I've calculated the moles an...

**Chemistry**

A 35 mL solution of HCl, reacts completely with 20 mL of 0.25 M KBr. What is the molarity of the HCl solution?

**Calculus**

A spherical balloon with a radius "r" inches has volume V(r)=(4/3)(pi)(r^3). Find the function that represents the amount of air required to inflate the balloon from a radius of "r" inches to a radius of r+1 inches.

**Calculus**

What is wrong with the following reasoning??? f(x) = 2^x f'(x) = x[2^(x-1)] Although n x^(n-1) is the derivative of x^n, you cannot apply similar rules when x is the exponent and the number being raised to a power is a constant. The derivative of b^x, where b is a constant...

**Chemistry**

Are propane, methoxymethane, and ethanol soluble in water? yes http://www.chem.lsu.edu/lucid/tutorials/solubility/Solubility.html Henry is wrong.

**Chemistry**

Calculate the end point pH, when 25 mL of 0.01 mol/L HCl solution reacts exactly with 25 mL of 0.1 mol/L NH4OH solution. NH3 Kb = 1.8 x 10^-5 This will be the pH of NH4Cl solution. NH4+ + HOH ==> NH3 + H3O^+ Ka = Kw/Kb = (NH3)(H3O^+)/(NH4^+). Solve for H3O^+, then pH = - lo...

**Chemistry**

Calculate the pH of a solute where 24.5 mL of 0.1 mol/L HCl is added to 25.0 mL of 0.1 mol/L NaOH. How much excess OH is there? .5ml .1M or 5E-5 moles. That is in a volume of 49.5ml So if OH concentration is that moles/volume, what is the H+ concentration? Remember the product...

**Chemistry**

Classify the following as: Weak or strong acid, weak or strong base, salt (from weak/strong acid and base). If appropriate, split the formula into its component ions. HNO3 So far, all I have is: HNO3 + H2O -> NO3^- + H3O^+ And I know HNO3 is a strong acid. What would I do n...

**Chemistry**

Use the Bronsted-Lowry definitions to identify the two conjugate acid-base pairs in the following acid-base reaction: H20 + H20 <-> H30^+ + OH^- Let's see what you think on this after the previous post. Just remember, the acid is the one that HAS the H and the base i...

**Chemistry**

Use the Bronsted-Lowry definitions to identify the two conjugate acid-base pairs in the following acid-base reaction: HCO3^- + S^2- <-> HS^- + CO3^2- I got it. HCO3^- is the base in the pair with CO3^2-. S^2- is the acid in the pair with HS^-. Would you believe you have ...

**Chemistry**

Zn + PbCl2 --> ZnCl2 + Pb The initial mass of a zinc strip is 2.684. After being left overnight in a lead (II) chloride solution, the mass of zinc is 2.581g. Calculate the Ksp of lead (II) chloride. So far I have: PbCl2 --> Pb(aq)2+ + 2Cl(aq)- Ksp = [Pb(aq)2+] [Cl(aq)-]^...

**English**

How is Hamlet a hypocrite towards Ophelia? I have one example, which is that he says he loves her but is the cause of her death because he rejects her and kills her father, which causes her madness and subsequent death. I need one more example, but I can't think of him act...

**English**

I posted this yesterday, that I need to modernize an Ancient Greek myth. bobpursely replied with an idea that I could do the Siren sisters as cheerleaders, but I couldn't find a myth about them, they're in two different myths. Like I've been thinking of myths such ...

**English**

I have to modernize an Ancient Greek myth, does anyone have any ideas? Sure. Reset the place and time of the Siren sisters (cheerleader sisters?) occupying a booth at the local Ice Creame shop, tempting Jason (basketball dude hero), Argo (Computer Programmer dude), and Odysseu...

**Calculus**

Why can't a equal 1 in y=log(base a) x. And why is x always positive in that? Hmmmm. a^y=x (from the problem statement). If a were to equal 1, then x would be 1 (1 to any power is 1). So if a is not one, but a positive number, then x has to be a positive number, if one is ...

**Calculus**

Find the inverse of each relation: y = (0.5)^(x+2) and y = 3log base 2 (x-3) + 2 For the first one I got y=log base 0.5 (x+2)...but the answer in the back of the textbook says that it is not x+2, but x-2. Can someone tell me why it would end up being x-2 and help me with the s...

**Calculus**

Express in exponential form: y = -log x with base 2 the - in front is like a -1 multiplied so write it as y = log2 x-1 then 2y = 1/x

**English**

How is Hamlet hypocritical with Rosencrantz and Guildenstern? Provide 2 examples. Please note that we don't do students' homework for them. Our tutors try to give you the information to help you complete your assignment on your own. Be sure to go back into your textboo...

**Calculus**

If f(x) is a continuous function, find the constants a and b such that f(x) = { -x -3 <= x <= -2 ax^2 + b -2<x<0 b x=0

**Calculus**

4) f(x)= { 3x^2 x< and equal 1 { ax+ b x > 1 What is the relation between a and b if the function is continuous for allof x.

**Calculus**

Create a function that has a graph with the following features: Two vertical asymptotes: x=1, x=3. One horizontal: y = -1. And x intercepts= -2, 4 how about f(x) = ((x+2)(x-4))/((3-x)(x-1)) ?

**English**

Hi, I'm writing an essay on "what makes a city world-class"...I have all of my points and everything set, I'm just stuck on how I should start my essay. I can't think of any good introductory sentence. Your introductory sentence should be something VERY a...

**Biology**

How is commercial root beer carbonated? Yeast-carbonated root beer contains a small amount of alcohol. ... which contain the same sort of artificial colors and flavors as commercial root beers. Since this is not my area of expertise, I searched Google under the key words "...

**Chemistry**

Can hypochlorite ions oxidize bromide to bromine? In acid solutions, yes. That's the old qual test for bromide. Shake a solution of the unknown with NaOCl, this oxidizes bromide to bromine, and the bromine colors the carbon tetrachloride layer (added previously) yellow. Of...

**Chemistry**

When hypochlorite ions act as an oxidizing agent, hydroxide ions are formed. What will this do to iron (II) or to iron (III) ions? Both Fe(OH)2 and Fe(OH)3 are insoluble in an aqueous solution.

**Biology**

What are the components of a photsynthetic unit, and what roles do they play? In which part of the chloroplast are photosynthetic units located?

**Biology**

Write an equation to summarize the photo reaction of photosynthesis. Since this is not my area of expertise, I searched Google under the key words "photosynthesis equation" to get these possible sources: (Broken Link Removed) http://en.wikipedia.org/wiki/Photosynthes...

**English**

I need to prove that Hamlet cares about/loves his mother or cared about her/loved her at one point. Since this is not my area of expertise, I searched Google under the key words "Hamlet mother love" to get these possible sources: http://72.14.253.104/search?q=cache:G...

**Chemistry**

Does the conversion of hydrogen peroxide to oxygen involve oxidation or reduction? What substance is acting as the oxidizer or reducer? and Does the conversion of hydrogen peroxide to water involve oxidation or reduction? What substance is acting as the oxidizer or reducer? Ox...

**English/GuruBlue**

I needed to write an essay on how Hamlet is a hypocrite and my three points were that he doesn't obey his father right away, he says he loves his mother but treats her badly, and he says he loves Ophelia but he is the cause of her madness. But now, my topic has been change...

**GuruBlue/English**

Yesterday, I asked the question about my thesis statement for Hamlet. Heres what I wrote: Hi, I'm writing an essay on how Hamlet is a participant of hypocrisy. Can anyone help me write a thesis statement. My points are that his father tells him to avenge him, but Hamlet ta...

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