Sunday

November 23, 2014

November 23, 2014

Total # Posts: 1,168

**Physics**

Marie Curie first identified the element radium in 1898. She found that the radium-226 (mass 3.77x10^-25 kg) decays by emitting alpha particle (mass 6.64x10^-27 kg). If the alpha particle's speed is 2.4x10^6 m/s, what is the speed of the recoiling nucleus?
*November 7, 2011*

**Chemistry**

Chemical analysis show that hemoglobin contains 0.34 percent Fe by mass. What is the minimum possible molar mass of hemoglobin? The actual molar mass of hemoglobin is four times this minimum value. What conclusion can you draw from these data?
*November 2, 2011*

**chemistry**

Benzene and cyclohexane molecules both contain six-membered rings. Benzene is a planar molecule, and cyclohexane is nonplanar. Explain.
*October 21, 2011*

**Chemistry**

Use the data in Table 15.3 (in the book Chemistry after Raymond Chang) to calculate the equilibrium constant for the following reaction: HCOOH(aq) + OH-(aq)= HCOO-(aq) + H2O(l)
*October 19, 2011*

**Trig**

Factor and simplify the expression. 1-sin^3 x
*October 16, 2011*

**trig**

Find tanx if sinx = 3/4 and x is in quadrant II.
*October 11, 2011*

**calculus**

How to factorise t3-8t2+16t?
*October 11, 2011*

**calculus**

How to factorise t3-8t2+16t?
*October 11, 2011*

**Statistics**

7. Give and interpret the 95% confidence interval for the hours of sleep a student gets.
*October 9, 2011*

**math**

what is 3z+(-10)=-19
*October 6, 2011*

**college prep english**

Ok so long story short I need help with homework......I have 3 questions on genre and its 2 genre's how do I know which one to write about ?
*October 3, 2011*

**chemistry**

An oxalic acid solution contains the following species in varying concentrations: H2C2O4, HC2O4-, C2O4^2-, and H+. Which of the above four species can act only as acids, which can act only as bases, and which can act as both acids and bases?
*September 29, 2011*

**CHEM**

The equilibrium constant for the reaction below is Kc = 9.1 10-6 at 298 K. 2 Fe3+(aq) + Hg22+(aq) 2 Fe2+(aq) + 2 Hg2+(aq) Calculate G when [Fe3+] = 0.21 M, [Hg22+] = 0.013 M, [Fe2+] = 0.022 M, and [Hg2+] = 0.020 M.
*September 29, 2011*

**chemistry**

1998 scientists using a special type of electron microscope were able to measure the force needed to break a single chemical bond. If 2.0 x 10^-9 N was needed to break a C-Si bond, estimate the bond enthalpy in kJ/mol. Assume that the bond had to be stretched by a distance of ...
*September 26, 2011*

**chemistry**

Most organic acids can be represented as RCOOH, where COOH is the carboxyl group and R is the rest of the molecule. (For example, R is CH3 in acetic acid, CH3COOH). (a) Draw a Lewis structure for the carboxyl group. (b) Upon ionization, the carboxyl group is converted to the ...
*September 26, 2011*

**Geometry**

a rectangle has an area of (2x^2 +12), a length of 9x+1) and a width of (3x-6). what is the value of x?
*September 25, 2011*

**Algebra**

If the formula R = -0.037t + 50.1 can be used to predict the world record in the 400 meter dash t years after 1925, for what years will the world records be 48.1 seconds or less?
*September 22, 2011*

**chemistry**

A student breaks a thermometer and spills most of the mercury (Hg) onto the floor of a laboratory that measures 15.2 m long, 6.6 m wide, and 2.4 m high. (a) Calculate the mass of mercury vapor (in grams) in the room at 20 degrees celcius. The vapor pressure of mercury at 20 ...
*September 21, 2011*

**chemistry**

If 10.00 g of water are introduced into an evacuated flask of volume 2.500 L at 65 degreed celcius, calculate the mass of water vaporized. (Hint: Assume that the volume of the remaining liquid water is negligible; the vapor pressure of water at 65 degrees celsius is 187.5 mmHg.)
*September 21, 2011*

**chemistry**

If 10.00 g of water are introduced into an evacuated flask of volume 2.500 L at 65 degreed celcius, calculate the mass of water vaporized. (Hint: Assume that the volume of the remaining liquid water is negligible; the vapor pressure of water at 65 degrees celsius is 187.5 mmHg.)
*September 21, 2011*

**chemistry**

Which of the following aqueous solutions would you expect to be the best conductor of electricity at 25 degrees celcius? Explain your answer. (a) 0.20 M NaCl (b) 0.60 M CH3COOH (c) 0.25 M HCl (d) 0.20 M Mg(NO3)2
*September 14, 2011*

**Physics I**

An Earth satellite moves in a circular orbit 770 km above the Earth's surface. The period of the motion is 100.0 min. What is the speed of the satellite? What is the magnitude of the centripetal acceleration of the satellite?
*September 13, 2011*

**Physics I**

A stone is projected at a cliff of height h with an initial speed of 48.0 m/s directed 60.0° above the horizontal. The stone strikes at A, 5.20 s after launching. Find the height, h, of the cliff. Find the speed of the stone just before impact at A. Find the maximum height...
*September 13, 2011*

**5th grade math**

what are the divisidles rules
*September 13, 2011*

**5th grade math**

what are the divisidles rules
*September 13, 2011*

**Chemistry**

the basis of oxidation number considerations, one of the following oxides would not react with molecular oxygen: NO, N2O, SO2, SO3, P4O6. Which one is it? Why?
*September 13, 2011*

**business**

Do you think that in the Post-Washington Consensus the developing world will be better off economically and politically
*September 10, 2011*

**chemistry**

A compound made up of C, H, and Cl contains 55,0 percent Cl by mass. If 9,00 g of the compound contain 4,19 x 10^23 H atoms, what is the empirical formula of the compound?
*September 7, 2011*

**pre-calculus**

Find the intercepts of the graph of x^2 + y^2 + 4xy - 2x + 7y = 8
*September 5, 2011*

**English**

We should either visit the art museum or attend a concert this weekend. Is this a parallel sentence?
*August 30, 2011*

**applied math**

how do you solve 2b+9=3
*August 30, 2011*

**math**

give expressions in the variable n, n ≥ 3 for the number of sugar cubes in the n*n*n cube with 0,1,2, or 3 painted faces, respectively
*August 30, 2011*

**Chem**

Is sea water close to being a saturated sodium chloride solution?
*August 29, 2011*

**accounting**

what is the journal entry if a owner of a company deposited $15,000 in their checking account. In return they received 1000 shares of common stock in their corporation. The par value of the common stock is $1 per share?
*August 26, 2011*

**math**

g(x)= 1-2x-3, x< or equal to 0. x-18, x>6 find g(6). so I used the first equation. 1/2(6)-3 and I got 0, but that's not the right answer so I'm not sure what I'm doing wrong.
*August 26, 2011*

**calculus**

Recall that a function G(x) has the limit L as x tends to infinity, written lim(x->infinity)G(x) = L, if for any epsilon > 0, there exists M >0 so that if x > M, then |G(x) − L| < epsilon. This means that the limit of G(x) as x tends to infinity does not ...
*August 1, 2011*

**calculus**

sorry, i meant ln(1-x) in the first sentence
*August 1, 2011*

**calculus**

You are right my expansion was incorrect ln(x-1) = series of (x^n+1)/n+1 = x + x^2/2 + x^3/3 i dont know why your terms are negative though. After i multiply (x + x^2/2 + x^3/3) by (1 + x^2/2! + x^3/3!) = x + x^2/2 + (x^3/2! + x^3/3) = x + x^2/2 + 5x^3/6 I dont understand why ...
*August 1, 2011*

**calculus**

the question asks to use power series though. So i found the power series of ln(1-x) = Series of nx^n-1 and for e^x is the series of x^n/n! i then found the first three terms of each ln(1-x) = 1 + 2x +3x^2 e^x = 1 + x^2/2! + x^3?3! after multiply them i got 1 + 2x + (X^2/2!+3x...
*August 1, 2011*

**calculus**

Use multiplication of power series to find the first three non-zero terms of the Maclaurin series of e^x ln(1 − x).
*August 1, 2011*

**calculus**

wait. aren't all the odd terms positive? since its (-1)^n-1? because if you sub n=3, it becomes (-1)^2, which is positive? And thank you once more. This was very helpful!
*July 31, 2011*

**calculus**

So, you're saying that when you separate an alternating series into two (odd and even) then the (-1)^n-1 goes away? And why did you make S1 negative, but not S2. And do i need to find the sum for S2 to answer the question? Because i only know how to find the sum of ...
*July 31, 2011*

**calculus**

im confused. I was taught that if it is an alternating series then you can only use the alternating series test to see if it was diverging or converging. And i did the alternating series test and all the conditions were met for each series seperately.
*July 31, 2011*

**calculus**

Show that the series(−1)^n−1(bn) where bn = 1/(n^1/2) if n is odd and bn = 1/2^n if n is even, diverges. Why does the alternating series test fail?
*July 31, 2011*

**phiisical science**

Suppose an unknown substance has a melting temperature of 1,200 degrees Celsius and a density of 16.7 g/cm3.
*July 26, 2011*

**thermodynamic**

A rigid vessel of 1m^3 contains steam at 20 bar and 400 degree C. the vessel is cooled until the steam is just dry saturated. Calculate the mass of steam in the vessel.
*July 17, 2011*

**algebra**

The perimeter of a square is equal to its area plus four. What is the measure of one side of the square?
*July 2, 2011*

**Algebra II**

Solve 1. 3x^2-9x=0 2. 12x^2+30x=-12 3. 9a(a+1)=4 4. 16x^2=25
*July 1, 2011*

**Health Psychology**

Ok, thank you. I believe I also need to add one more psychologist to the list, making it 5 different psychologists, but I was under the impression I only had to assign 1 job to each. Thank you for clearing this up for me. This helps so much to get a second out look. :)
*June 24, 2011*

**Health Psychology**

I want to make it clear that I do not want any answers to the project I am about to post on here. I only need help understanding it a little. I am trying to get online to speak with my professor but our school site is down at the moment. I think I know what I am doing, I just...
*June 24, 2011*

**physics**

a spring has a force constant of 20000 N/m how far must it be strectched for its potential energy to be 43 J??
*June 24, 2011*

**college algebra**

2/5(5x-3) - 1/3(12x-5). Have the correct answer but need someone to show me how to solve for it.
*June 20, 2011*

**Algebra**

Elena bicycles 4 km/h faster than Robert. In the same time it takes Robert to bicycle 27km/h, Elena can bicycle 39 km. How fast does each bicycle travel?
*June 19, 2011*

**chemistry**

Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction: 2 NO(g) + O2(g) → 2 NO2(g), ΔH°rxn = ? Given: N2(g) + O2(g) → 2 NO(g), ΔH°rxn = +183 kJ 1/2 N2(g) + O2(g) → NO2(g), ΔH°rxn = +...
*June 14, 2011*

**chemistry**

According to the following thermochemical equation, what mass of H2O (in g) must form in order to produce 975 kJ of energy? SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l), ΔH°rxn = -184 kJ
*June 14, 2011*

**chemistry**

A 4.98 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter with a heat capacity of 4.25 kJ/°C. If the temperature rose from 29.5°C to 69.8°C, determine the value of ΔH°comb for aniline.
*June 14, 2011*

**5th grade math**

If you roll two number cubes numbered 1-6, what is the probability of rolling the same number on each cube?
*June 12, 2011*

**English**

I need help writing a paragraph using these words. Retrospect, Inane, Squelch, Subsidize, and Lethargy.
*June 1, 2011*

**biology**

what school you go to
*June 1, 2011*

**Chemistry**

Given the equilibrium: CO + 2H2 = CH3OH H=-18.0kJ How will the concentration of CO at equilibrium be affected by the following? a) Adding more CH3OH b) Removing some H2 c) Reducing the temperature. I don't understand how i'm supposed to figure these out.. please help!
*May 31, 2011*

**Chemistry 12 **

Why doesn't stirring not affect solution equilibrium??
*May 31, 2011*

**Chemistry**

OMG Doctor Bob you are a huge help! And you right i did have that a dozen times lol but i wasn't sure if i had it right because i couldn't het the last part to work out for me! But i have it now so thanks a bunch!
*May 28, 2011*

**Chemistry**

Balance the following redox equation by the oxidation number methode Ag + HNO3 = AgNO3 + NO + H2O I have all the oxidation numbers i just don't understand how i'm supposed to balance it according to them. I read the sites and i can't get it. Do i balance out each ...
*May 28, 2011*

**english**

Can you fix this sentence? "When the movie Star Wars premiered in 1977, it was both surprising and a revolution in its special effects."
*May 27, 2011*

**chem**

i have all the oxidation numbers for all the of elements but i don't understand how i'm supposed to balance the equation using the oxidation numbers. Do i have to to change the oxidation numbers to equation the same on each side?
*May 25, 2011*

**chem**

Balance the following redox equation by the oxidation number methode Ag + HNO3 = AgNO3 + NO + H2O
*May 25, 2011*

**chem**

How many grams of potassium permanganate (KMnO4) should be added to a 100 mL volumetric flask to prepare a 0.02505 M solution when the flask is diluted to the mark with water?
*May 18, 2011*

**trig**

how do you graph y=-(1/4)sin(3/4x+pi/8? include the amplitude, period, vertical translation, horizontal shift, and table of values please.
*May 11, 2011*

**finite math**

i used x instead of t. thanks
*May 7, 2011*

**finite math**

As online attacks persist, spending on information security software continues to rise. The table gives the forecast for the worldwide sales (in billions of dollars) of information security software through 2007 (t = 0 corresponds to 2002): Year, t 0 1 2 3 4 5 Spending, y 6 8....
*May 7, 2011*

**finite math**

thanks sooooo much!
*May 7, 2011*

**finite math**

Kane Manufacturing has a division that produces two models of hibachis, model A and model B. To produce each model-A hibachi requires 3 lb of cast iron and 6 min of labor. To produce each model-B hibachi requires 4 lb of cast iron and 3 min of labor. The profit for each model-...
*May 7, 2011*

**finite math**

(281.82-250)*48?
*May 7, 2011*

**finite math**

i got $198.87 what about the interest charges?
*May 7, 2011*

**finite math**

The price of a new car is $16,000. Assume that an individual makes a down payment of 25% toward the purchase of the car and secures financing for the balance at the rate of 6%/year compounded monthly. (Round your answers to the nearest cent.) What monthly payment will she be ...
*May 7, 2011*

**finite math**

i put 5.78% and it says it's wrong.
*May 7, 2011*

**finite math**

Carlos invested $6,000 in a money market mutual fund that pays interest on a daily basis. The balance in his account at the end of 8 mo (245 days) was $6,230.23. Find the effective rate at which Carlos's account earned interest over this period (assume a 365-day year). (...
*May 7, 2011*

**geometry**

how to solve y= (x-2)^2+4 4x+2y=14 algebraically
*May 4, 2011*

**English**

thanks
*May 4, 2011*

**English**

My cpu is not letting me view this page
*May 4, 2011*

**English**

What would you say this line ment: I am the chosen no hand saves?
*May 4, 2011*

**Program planning and evaluation**

I dont know
*May 1, 2011*

**chemistry**

What is the mole fraction of sulfuric acid in a solution made by adding 3.4 grams of sulfuric acid to 3500 mL of water?
*April 28, 2011*

**chemistry**

how many grams of glucose C6H12O6 would you need to make 250 mL of 1.0 M solution?
*April 28, 2011*

**chemistry**

how many moles of sucrose C12H22O11 does 300mL of a 0.10 M sucrose solution contain?
*April 28, 2011*

**ah trig help**

use an apropriate sum or difference indentity to prove the double-angle identity cos2u=1-2sin2u
*April 26, 2011*

**trig identies 5.3 &5.4**

i got it nevermind
*April 26, 2011*

**english**

an ode
*April 24, 2011*

**US History**

1. Which three amendments that were passed almost 100 years earlier, guaranteed that African-Americans had the right to vote? 2. Why was the Voting Rights Act of 1965 necessary? 3. Name three ways that local jurisdictions tried to inhibit African-Americans from voting prior ...
*April 24, 2011*

**Chemistry**

At which temperature will the following reactions reverse? Use the thermodynamic date provided at the end of the book. a) 2Ca(s) + O2(g) -> 2CaO(s) b) 2CH4(g) + 4 O2(g) -> 2CO2(g) + 4H2O(g)
*April 7, 2011*

**Chemistry**

The trick is that the heat lost from the metal is equal to the heat gained by the water. So q lost = f gained. Since the metal went from 100.0C to 32.5C I'd say it lost. The water went from 20.0C to 32.5C, so it gained. "q" then represents the metal and "f&...
*April 6, 2011*

**chemistry**

Is it possible to produce a form of sodium ferrate using these components? FeCl3 NaOH NaOCl
*April 5, 2011*

**English**

A critic should read a story more than once in order to write about it. True or False.
*April 5, 2011*

**Math**

Postal regulations specify that a package sent by priority mail may have a combined length and girth of no more than 129 in. Find the dimensions of a cylindrical package with the greatest volume that may be sent by priority mail. Hint: The length plus the girth is 2πr + l...
*April 4, 2011*

**5th Grade Math/Making a Duplicate**

a canoe is 5.67 how much is it in cm
*March 29, 2011*

**Chemistry**

At a particular temperature, K = 3.75 for the following reaction. SO2(g) + NO2(g) <==> SO3(g) + NO(g)\ If all four gases had initial concentrations of 0.550 M, calculate the equilibrium concentrations of the gases.
*March 27, 2011*

**math **

(x/4−1/x)/(1/2x+1/4)
*March 27, 2011*

**Physics**

A sled of mass 5.98 kg is coasting along on a frictionless ice-covered lake at a constant speed of 1.42 m/s. A 1.98-kg book is dropped vertically onto the sled. At what speed does the sled move once the book is on it?
*March 27, 2011*

**geometry**

How do I solve this? 4/3PI*R^3 When R=6 I get 288 if I do it in PI form. Just seems really high.
*March 21, 2011*

**Alegebra**

i have 5 questions, i dont know how to solve these questions. 7= 2 +5(z-2) 15(s-3)=12s-43 2a-6=3(a-4) 2(b-3)+5=3(b-1) 6x +7 / 5 = x
*March 11, 2011*

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