Thursday

November 27, 2014

November 27, 2014

Total # Posts: 61

**gen chem**

use the rydberg equation to calculate the wavelength in A of the photon absorbed when a hydrogen atom undergoes a transition from n=7 to n=9
*November 26, 2014*

**MATHS**

please help me ...Experiments show that radium at rate proportional to the amount of radium present at the moment . if half life is 1590 years what percentage will disappear in one year ??
*September 26, 2014*

**MATHS**

experiments show that radium disintegrates at a rate proportional to the amount of radium present at the moment . if half life is 1590 years what percentage will disappear in one year?
*September 26, 2014*

**history**

middle east, late 1300's-1700's
*July 13, 2014*

**history**

ways non-Muslims were treated in the Islamic world?
*July 13, 2014*

**math**

Find opxthe volume of a rectangular box 9 feet by 7.1 feet by 7 feet.
*September 1, 2013*

**TRIGONOMETRY**

Suppose tan theta=15pi/18 is less than theta 3pi/2 , what are the other trigonometric functions?
*July 9, 2013*

**Chemistry**

Given the balanced equation: a. Fe2O3+3C=2Fe+3CO: b. How many moles of Fe are produced when 1.36 moles of carbon monoxide are produced? c. How many grams of Fe is part b equal to? d. how many molecules of Fe are in part B
*October 8, 2012*

**trig**

Determine the period, amplitude and phase shift for each given function: A)y = -4 cos 3x + 5 B)y = 2/3 sin (30x-90degrees)-10 c)y = -0.38 tan (x/3+pi/3) d)y = pi cos(2x)+ pi
*August 12, 2012*

**trigonometric identities**

Prove the following trigonometric identities 1. tanx = sinx + sin^2x/cosx(1+sinx) 2. cos^3+(cosx)(sin^2x) = 1/secx
*June 22, 2012*

**Math (please help!)**

feta = β
*June 11, 2012*

**Math (please help!)**

1. θ is a first quadrant angle in standard position and cos 1/(sqrt10)= . Find the exact value of sin . 2. feta is a second quadrant angle in standard position and tan(feta) -((sqrt5)/2) = . Find the exact value of cos(feta) . 3. θ is an angle in standard position ...
*June 11, 2012*

**math**

Simplify each of the following: 1. 16*(2^x)+2 2. 3[sqrt(x^1/4)*sqrt(x)/5*sqrt(x^2)] 3. ab^(2x+y)/a^x b^x
*May 28, 2012*

**math (please double check my answers)**

Simplify the following using the laws of exponents: Need help with these: a) (9)^1/2 x 4^2/24 b) 16 x 2^x+2 Simplify each of the following: b) b) 3 sqrt x^1/4 sqrt x/ 5 sqrt x^2 c) (ab)^2x+y /a^x b^y Need these answers double checked: c) 3^-8/3^-6 x 3^-5 3^-8/3^-6+-5 3-8^ 3^-...
*May 27, 2012*

**math**

It's f(x) = .25(4^x) - 2 Thank you!
*May 27, 2012*

**math**

5. Find the slope of the secant to the curve f(x) = 0.25(4)^x - 2 between: i) x = 0 and x = 1 ii) x = 0 and x = 0.5 iii) x = 0 and x = 0.1 iv) x = 0 and x = 0.01
*May 27, 2012*

**math**

7. Determine the inverse of each relation given. a. f(x) = 1/x-2 + 3 b. f(x) = 2(x – 4)^2 + 5
*May 24, 2012*

**Math (need formula)**

I would be very appreciative if someone could provide me with the formula I would use to plug these figures into a graph. 3. A 2m length of board rests with one end on the floor and the other end on a small stack of bricks. A baseball is rolled up the board and back down again...
*May 16, 2012*

**Physics**

When a 0.50 kg-object is attached to a vertically supported spring, it stretches 0.10 m from the equilibrium position. Find k for the spring.
*February 22, 2012*

**physics**

Given x(t) = xm cos 2ðt/T for a spring with constant k and attached mass m sketch as a function of t, (a) the displacement x, (b) the velocity v, (c) the acceleration.
*February 22, 2012*

**calculus(integral)**

intergral 2x^2/(x^2+4x+8)
*February 11, 2012*

**dependance of a man on the enviroment**

How do deforestation and urban sprawl affect the greater food web?
*January 28, 2012*

**mind and machine**

What figure from the history of philosophy section do you think might have some views that are similar, or at least relevant, to your own?
*August 24, 2011*

**physical chemistry**

find the ph of the solution that results from the addition of 25ml of 0.1mol/l NaOH solution to 50ml of 0.1mol/l HCL solution?
*April 26, 2011*

**Chemistry**

A flask partially full of liquid water is heated to boiling and capped cold water is poured over the flask. The water boils even more vigorously explain
*April 11, 2011*

**physics**

Quartz has a refractive index of 1.54. If light from a HeNe laser impinges on an air/quartz interface at an angle of 22.5 degrees, what is the angle of refraction?
*April 6, 2011*

**physics**

Calculate the frequency in hertz, wavelength in nm, and the velocity in m/s of light inside a material with a refractive index of 1.39. In vacuum, the light has a wavelength of 514.5nm
*April 5, 2011*

**chemistry**

the work done by the system during a certain adiabatic process is 200J. What is the change in U of the system
*February 6, 2011*

**chemistry**

if PV=RT + ἁP where ἁ is a constant Calculate the work if the gas is heated at constant pressure from T1 to T2 Calculate the work if the gas is expanded isothermally and reversibly
*February 2, 2011*

**Chemistry**

what would be the effect on a chromatographic peak of introducing the sample at too slow a rate
*January 31, 2011*

**chemistry**

how would the graph of Pressure vs Volume look for a sample of an ideal gas that has a volume of 1 L at 0 degrees Celsius and 1 bar. How would the graph of Pressure versus volume look for sample of gas at the same conditions but at 100 degrees Celsius?
*January 25, 2011*

**statistics**

what is the 4σ rule of thumb in statistics
*January 25, 2011*

**chemistry**

calculate the rms speeds of He at 10, 100, and 1000 K in meters per second and in miles per hour. What values would be otained if the pressure was 10^-10 bar
*January 23, 2011*

**chemistry**

But the problem didnt give temperature that is qhat confused me
*January 22, 2011*

**chemistry**

calculate the pressure (in Pascals and bar) of 10^23 gas particles each with a mass of 10^-25 kg, in a 1 L container if the rms speed is 100m/s? What is the total kinetic energy of these particles? What is the temperature inside the container
*January 22, 2011*

**chemistry**

calculate the pressure in Pa and bar of 10^23 gas particles each with a mass of 10^-25 kg, in a 1 liter container if the rms speed is 100m/s
*January 22, 2011*

**Chemistry**

0.10 M potassium chromate is slowly added to a solution containing 0.50 M AgNO3 and 0.50 M Ba(NO3)2. What is the Ag+ concentration when BaCrO4 just starts to precipitate? The Ksp for Ag2CrO4 and BaCrO4 are 1.1 x 10-12 and respectively.
*January 16, 2011*

**chemistry**

Calculate the pH of a 0.800 M NaCH3CO2 solution. Ka for acetic acid, CH3CO2H, is
*January 16, 2011*

**chemistry**

If 0.10 M potassium chromate is slowly added to a solution containing 0.50 M AgNO3 and 0.50 M Ba(NO3)2. What is the Ag+ concentration when BaCrO4 just starts to precipitate? The Ksp for Ag2CrO4 and BaCrO4 are 1.1 x 10-12 and respectively.
*January 16, 2011*

**science**

Ammonia gas can be prepared by the reaction of a metal oxide such as calcium oxide with ammonium chloride. CaO(s) + 2 NH4Cl(s) 2 NH3(g) + H2O(g) + CaCl2(s) If 199 g of CaO and 300. g of NH4Cl are mixed, what mass of NH3can be produced?
*September 16, 2010*

**chemistry**

A piece of metal weighing 26g is immersed in a quantity of water in a graduated cylinder. The initial volume of the water was 16.0 ml and volume of water plus metal is 22.0 ml. The density of metal in g/ml is? If you get this right i will hand you over my beach front property ...
*July 21, 2010*

**chemistry**

What is the oxidation number of PO4 in the compound Ca3(PO4)2? how do you get it?
*July 21, 2010*

**math**

to answer this question you need to know the formula for the circumference of a circle is: circumference = pi * 2r and a circle is 360 degrees. so the length of the arc is what fraction of the whole circle? and that fraction times the above circumference formula is your answer
*March 30, 2010*

**math**

base figures you need to know 5280 feet in a mile 12 inches in a foot 60 minutes in an hour The circumference of a circle formula is circumference = pi * radius * 2 the trick of this problem is you have feet in the mile but inches in the tire & hours in the speed but minutes ...
*March 30, 2010*

**math**

g) 30 = 30 * .25 + (30+10) * .10 30 * .25 + 40 * .10 7.50 + 4.10 11.50
*February 25, 2010*

**history**

hey coould anyone tell me is the title lord in the 1700's england was compatible with involvement in the royal navy?
*September 17, 2009*

**religion**

he wasn't fully human- he was human and fully God. he came as a human to absorb the wrath God had to use to punish sin. Jesus did that for all who trust in him and his grace. otherwise...
*August 31, 2009*

**Maths**

How do I work out square roots without a calculator?
*August 28, 2009*

**If...=, find...**

If h(x)=3/(2x+1), find h^-1(x)
*July 27, 2009*

**religion**

his death itself wasn't the point. It was his ressurection. God poured the wrath meant for sinners on the only substitute possible, his son. he died, and payed the price on the cross as he died. but he was ressurectred after 3 days, so anyone who trusts in him will be saved
*June 11, 2009*

**pre-algebra**

how do i identify the slope snd y-intercept of the graph of each equation. Then graph the equation? plz help asap!
*February 26, 2009*

**Chemistry**

Classify each of the following actions by whether it causes a leftward shift, a rightward shift, or no shift in the direction of the net reaction. N2(g)+ O2(g)=2NO(g)
*February 5, 2009*

**Computers**

How would you test an object-oriented design’s sequence diagrams? Be specific.
*October 22, 2008*

**math riddle ALGEBRA WITH PIZZAZZ**

O'lay ,like that company that does hair shampoos or O'lay at a bull fight :) Si' hablo españole'
*September 14, 2008*

**geometry**

ok, so i don't understand this question. : which postulate justifies the following statement? "exactly one plane contains <(angle)ABC"??? i don't get what i'm supposed to answer and i don't even understand what it's trying to say. and i've ...
*October 21, 2007*

**History**

What's the difference between COMECON and COMINIFORM? Thanks in advance! http://en.wikipedia.org/wiki/Comecon http://en.wikipedia.org/wiki/Cominform
*April 24, 2007*

**1st grade math please help!!!**

8...
*April 24, 2007*

**HISTORY...**

What is the EU (European Union)? Was is successful? Why or why not? The EU now consists of most countries of Europe. It started out as the "Common Market" following World War II and kept growing. It is very successful. More countries are eager to join. The Euro is, ...
*April 24, 2007*

**HISTORY**

Does this sentence make any sense and is it accurate? The Soviet Union, however, rejected the Marshall Plan due to the belief that they could not keep a close eye on the satellite states in the Eastern bloc and that the West was trying to enforce their democratic ideas. ++++ ...
*April 24, 2007*

**Biometrics II**

If these samples were drawn from a population with mean male weight of 180 and mean female weight of 165, what is the probability that the difference between the mean male and female weights would lie between 4.5 and 27.8?
*February 25, 2007*

**Biometrics**

If these samples were drawn from a population with mean male weight of 180 and mean female weight of 165, what is the probability that the difference between the mean male and female weights would be greater than the observed sample? (The sample means are female 167.2 with a ...
*February 25, 2007*

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