Tuesday

September 27, 2016
Total # Posts: 1,755

**Chemistry**

The rate constant for this first order reaction is 0.440s-1at 400 C. A to products How long(in seconds) would it take for the concentration of A to decrease from 0.740 M to 0.290 M?

*July 19, 2011*

**Calculus**

find the exact value of sin 11pi/12 using the sum or difference formula.

*July 19, 2011*

**phys science**

A space shuttle orbits at an altitude of approximately 200km above the surface of the Earth. If the radius of the Earth itself is 6380 km, what’s the acceleration due to gravity at the altitude of the space shuttle?

*July 18, 2011*

**calculus **

Verify the identity cot2 beta/1+csc beta=1-sin beta/sin beta.

*July 17, 2011*

**Chemistry**

No its not a typo but I did put the wrong activation energy. Its suppose to be a certain reaction has an activation energy of 37.70kj/mol. At what kelvin temperature will the reaction proceed 3.00 times then it did at 303k? I was working the problem and got stuck on finishing ...

*July 17, 2011*

**Chemistry**

No its not a typo but I did put the wrong activation energy. Its suppose to be a certain reaction has an activation energy of 37.70kj/mol. At what kelvin temperature will the reaction proceed 3.00 times then it did at 303k? I was working the problem and got stuck on finishing ...

*July 16, 2011*

**Chemistry**

A certain reaction has an activation energy of 37.30 kj/mol. At what Kelvin temperature will the reaction proceed 3.00 times then it did at 303 k?

*July 16, 2011*

**Chemistry**

After 79 mins 20.0% of a compound has decomposed. What is the half life of this reaction assuming first-order kinetics?

*July 16, 2011*

**Chemistry **

The rate constant for this first order reaction is 0.0470 s-1 at 400 C. A TO Products After how many seconds will 11.0% of the reactant remain?

*July 16, 2011*

**Chemistry**

The rate constant for this first-order reaction is 0.440 s-1 at 400 C. A to products How long in seconds would it take for concentration of A to decrease from 0.740 M 0.290 M?

*July 16, 2011*

**Chemistry**

Determine the average rate of change of B from t=0s to t=352s. A to 2B Time Concentration of A (M) 0 0.670 176 0.385 352 0.100

*July 16, 2011*

**Chemistry**

Determine the average rate of change of B from t=0s to t=352s. A to 2B Time Concentration of A (M) 0 0.670 176 0.385 352 0.100

*July 16, 2011*

**Chemistry**

The rate of the following reaction is 0.480 M/s. What is the relative rate of change of each species in the reaction? A+3B=2C

*July 16, 2011*

**Pre Calculus**

use the sum of difference formula what is sin(pi/2-5pi/3)?

*July 14, 2011*

**Chemistry**

at 298 k, the Henry's law constant for oxygen is 0.00130 M/atm. Air is 21.0% oxygen. at 298 k, what is the solubility of oxygen in water exposed to air at 1.00 atm?

*July 12, 2011*

**Chemistry**

The boiling point of an aq solution 102.11 C. What is the freezing point?

*July 12, 2011*

**Chemistry **

The boiling point of an aq solution 102.11 C. What is the freezing point?

*July 12, 2011*

**Chemistry **

A solution of H2SO4 with a modal concentration 6.25m has a density of 1.300 g/ml. What is the molar concentration?

*July 12, 2011*

**Chemistry**

what is the mole fraction of solute molality concertration for an aqueous solution that is 19% NaOH by mass?

*July 12, 2011*

**Calculus**

Given f(x)=-10x2-42x-17 find f(x+h)

*July 11, 2011*

**Calculus **

Express the quadratic function y=-2/3x2-12x-11 in standard form?

*July 11, 2011*

**Calculus**

Given m(x)=7/5x2+9-2 what is the domain of m in set notation form?

*July 11, 2011*

**physics**

A spring-loaded toy gun is used to shoot a ball of mass m straight up in the air. The spring has spring constant k. If the spring is compressed a distance x_0 from its equilibrium position ( y = 0 ) and then released, the ball reaches a maximum height h_max (measured from the ...

*July 9, 2011*

**Chemistry**

1. The vapor pressure, P of a certain liquid was measured at two temperatures, T. from this data: T(K) and P(kpa) 275 3.57 825 6.57 for the enthalpy how would this be plotted on the graph point 1: point 2: 2. What is the rise, run, and slope 3. What is the enthalpy of ...

*July 9, 2011*

**Chemistry**

1.The density of solid Fe is 7.87 g/cm3. What volume per atom of Fe? 2.As a solid Fe adopts a body centered cubic unit cell. What is the volume of a unit cell of this metal? 3.What is the edge length of a unit cell of Fe?

*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? I need help in setting the problem: I got 56.21/8.3145j/mol.k(1/T1-1/T2)?

*July 9, 2011*

**Chemistry **

x+y=9.0 0.50x+0.20y=3.90 What is the value of x and y?

*July 9, 2011*

**Chemistry practice**

My mistake I meant x+y=9.0 0.50x+0.20y=3.90 What is the value of x and y?

*July 9, 2011*

**Chemistry practice**

x+y=9.0 0.50+0.20y=3.90 What is the valuse of x and y?

*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? Thank you

*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? Thank you

*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? Thank you

*July 9, 2011*

**Chemistry**

Two 20.0g ice cubes at -10.0 C are placed into 275g of water at 25.0 C. Assuming no energy is transferred to or from the surroundings, calculate the final temperature of the water after all the ice melts.

*July 9, 2011*

**Chemistry **

Calculate the heat energy released when 19.6 of liquid mercury at 25.00 C is converted to solid mercury at its melting point

*July 9, 2011*

**Algebra 2**

Simplify: a+1/a-1 times a^2-1/(a+1)^2

*July 4, 2011*

**Algebra 2**

Simplify: (x^3-4x)(x^2-4x+4)^-1

*July 4, 2011*

**College Physics**

All of your math is correct except that h is just 36.7 because the bungee is attached to his feet not halfway up his body. Therefore his potential energy has to be measured to that point. Then you get mgh=1/2kx^2 k=(2mgh)/x^2 k=(2*93.1*9.8*36.7)/9.3^2 = 774.29 N/m

*June 29, 2011*

**calculus**

2x^3+3x^2-12x-7 the absolute maximum. I need help because it seems no one else in my class knows how to.

*June 28, 2011*

**Physics**

Hey, it's me again, Can someone help me with this question? A water balloon is dropped from the top of a building. Assume the balloon does not break when it strikes the ground. If the water balloon falls a distance of 21m, what is the maximum temperature rise of the water ...

*June 28, 2011*

**Physics**

"The energy that is transferred as heat to or from the object with the larger heat capacity must be greater than the energy that is transferred as heat to or from the object with the smaller heat capacity." Can someone explain why this concept is true or false?

*June 21, 2011*

**writing**

thank you those helped a lot! thanks!

*June 20, 2011*

**writing**

i need help on a theme statement for "cask of amontillado"

*June 20, 2011*

**Math**

A rectangular lot is to be fenced using 80m of fencing. What is the maximum area and what are the dimensions of the lot?

*June 19, 2011*

**chemistry**

1. 15.0 g of sodium sulfate are dissolved in water to form 400.0 g of solution. The density of the solution is 1.056 g/mL at 25oC. a. What is the mass percent (%(w/w)) of sodium sulfate? b. What is the molarity of sodium sulfate? c. What is the molarity of the sodium ion? d. ...

*June 13, 2011*

**Information Technology**

I have this assignment due tonight in about 2 and a half hours. I am going to try to finish it the best that I can but I do not know if I will be able to. I really am stuck. I have no idea where to even start on this. Can somebody please help?! • Read the following ...

*May 28, 2011*

**math**

0.8T = 24

*May 24, 2011*

**physics**

Assume that here in sussex we live at exactly latitude 45 degress. Calculate the tangential speed, in m/sec and in mph that we are rotating at

*May 19, 2011*

**Chemistry**

When 1.187g of a metallic oxide is reduced with excess hydrogen, 1.054g of the metal is produced. How do you determine what the metal oxide is?

*May 18, 2011*

**College Physics**

Two shuffleboard disks of equal mass, one orange and the other yellow, are involved in a glancing collision. The yellow disk is initially at rest and is struck by the orange disk moving with a speed vi. After the collision, the orange disk moves along a direction that makes an...

*May 18, 2011*

**College Physics**

A 7.00 g bullet, when fired from a gun into a 1.00 kg block of wood held in a vice, penetrates the block to a depth of 8.00 cm. If the block had instead been at rest on a frictionless horizontal surface, to what depth would the bullet have penetrated?

*May 18, 2011*

**Chemistry**

Calculate the normality of 5 M HCl

*May 9, 2011*

**Chemistry**

How many grams of H2SO4 are contained in 4.5L of .30 N sulfuric acid?

*May 9, 2011*

**Chemistry**

What mass of K2SO4 would you measure out to prepare 550mL of a .76 M solution?

*May 9, 2011*

**Physics**

So would that just be .65/1.8 and the answer is 0.36?

*May 7, 2011*

**Physics**

A student reading his physics book on a lake dock notices that the distance between two incoming wave crests is about 0.65 m, and he then measures the time of arrival between the crests to be 1.8 s. What is the approximate speed of the waves?

*May 7, 2011*

**algebra**

Given the function f(x) = −2x + 4, find x if f(x) = 20

*May 7, 2011*

**Physics**

a. Correct b. Incorrect c. Incorrect d. Correct e. Incorrect

*May 4, 2011*

**physics**

he question is: A spherical capacitor contains a solid spherical conductor of radius 0.5mm with a charge of 7.4 micro coulombs, surrounded by a dielectric material with er = 1.8 out to a radius of 1.2mm, then an outer spherical non-conducting shell, with variable charge per ...

*May 1, 2011*

**physics**

you see lightning and then count 4 seconds till you hear the thunder. From this you conclude that the lightning strike occurred_______ a. 1400m away b. 700m away c. none of the above Can you please show me how to figure out how to get the answer?

*May 1, 2011*

**physics**

These are problems I have been stuck on and can't figure out. Help would be greatly appreciated. 1. Blue and yellow light combinte to produce white light because ______ (Please explain what it's the correct answer) a.they absorb each other's wavelengths b. blue, ...

*April 30, 2011*

**Business Law- Ethics**

I'm not sure how to go about doing this. I feel like it's an easy question but im thinking to far into it. I want to say that Davis would be the first person to be let off & Carter would be the last person to be let off. I'm not sure what order the rest would be in...

*April 28, 2011*

**math**

4cot^2x-4/tanx+cosxsecx factorin algenraic single trig function

*April 26, 2011*

**math (pre calc)**

4cot^2x-4/tanx+cosxsecx write expression in factored form as an algebraic expression of a singletrig function

*April 26, 2011*

**math**

A Crime Wave

*April 25, 2011*

**math**

solve using the substitution method: 8x+5y=-12 x=12-4y

*April 17, 2011*

**precalculus**

An experiment begins with 8 cells, and the number of cells triples every week. If the expression a(b)^q computes the number of cells that are present q days after the experiment begins, how much is the value of b?

*April 13, 2011*

**Precalculus**

The bacteria in a 8-liter container double every 2 minutes. After 55 minutes the container is full. How long did it take to fill a quarter of the container?

*April 13, 2011*

**Chemistry**

Due to increased CO2 in the atmosphere, the pH of rainwater is more acidic than in the previous century. Use the following data to calculate the pH of unpolluted rainwater at 25°C: vol% in air of CO2 = 0.033; solubility of CO2 in pure water at 25°C and 1 atm = 88 mL ...

*April 12, 2011*

**Math**

On a certain road 20% of the vehicles are trucks, 16% are buses and the remainder are cars. (i) A random sample of 11 vehicles is taken. Find the probability that fewer than 3 are buses. [3] (ii) A random sample of 125 vehicles is now taken. Using a suitable approximation, ...

*April 8, 2011*

**Chemistry**

youre just screwed

*April 6, 2011*

**Chemistry**

How fast should a 58.1g tennis ball travel to have a de Broglie wavelength that is equal to that of a photon of green light (5.40 X 10^3 angstroms)?

*April 5, 2011*

**government**

kayla

*April 4, 2011*

**Calculus**

If an open box has a square base and a volume of 106 in.3 and is constructed from a tin sheet, find the dimensions of the box, assuming a minimum amount of material is used in its construction. (Round your answers to two decimal places.) height in length in width in

*April 4, 2011*

**Math I'm so confused**

Find the absolute maximum and absolute minimum values, if any, of the function. (If an answer does not exist, enter DNE.) f(x) = x2 − x − 5 on [0, 5] Come someone please show me how to do these problems? I'm lost

*March 30, 2011*

**precalculus**

log4 60

*March 28, 2011*

**precalculus**

log 60 4 estimate the following log

*March 28, 2011*

**Chemistry**

spontaneous oxidation

*March 27, 2011*

**economics**

Consider an economy with the production function L^(1/3) a) Derive the Labor demand Curve b) If Labor supply curve is L^s= (w/p), calculate the equilibrium levels of real wage, labor and output. c) Assume M^s= 45 and k=3 . What is the equation of the aggregate demand curve for...

*March 27, 2011*

**CHEMISTRY**

The equilibrium constant for the reaction, SO2(g)+ NO2(g) <----> NO(g)+ SO3(g) has been experimentally determined as a function of temperature. The results are presented in the table below. T (°F) KC 285 662 752 156 842 93.4 932 59.6 1022 40.2 If 0.0791 ft3 SO2, 0....

*March 24, 2011*

**precalculus**

A population doubles every 30 years. Assuming exponential growth find the following: annual growth rate: % continuous growth rate: %

*March 23, 2011*

**chemistry**

2.00 L of NO(g) at 1.00 atm and 25°C is reacted with 1.00 L of H2(g) at 2.00 atm and 25°C according to the following unbalanced equation. NO(g) + H2(g) ® N2(g) + H2O(g) Which, if either, is the limiting reactant?

*March 23, 2011*

**math**

the edges of 3 cubes are consecutive odd intergers. if the cubes aer stacked on a desk as shown, the total exposed surface area is 381. find the lenths of the sides of the cubes thanks!!

*March 21, 2011*

**separation of variables**

If dy/dt=-3y and if y=1, what is the value of t for which y=1/3? I got y=e^(-3t) but I wasn't for sure if it was correct.

*March 21, 2011*

**separation of variables**

how do you separate the variable dy/dx=-xy^2, y(1)=-0.25

*March 21, 2011*

**separation of variables**

how do you solve the variable dy/dx=-x^2y^2, y(4)=4

*March 21, 2011*

**separation of variables**

how do you separate the variable dy/dx=x^2/y given y=-5 when x=3

*March 21, 2011*

**separation of variables**

Find an equation of the curve that passes through the point (1,1) and whose slope at (x,y) is y^2/x^3.

*March 21, 2011*

**Chemistry**

Calculate the enthalpy of reaction. D + F --> G + M using the following equations and data: G + C --> A + B ΔH = +277 kJ C + F --> A ΔH = +303 kJ D B --> M ΔH = -158 kJ

*March 21, 2011*

**separation of variables**

If dy/dx=-3y and if y=1, what is the value of t for which y=1/3? I got y=e^(-3t) but I wasn't for sure if it was correct.

*March 21, 2011*

**Chemistry**

Calculate the enthalpy of reaction. D + F --> G + M using the following equations and data: G + C --> A + B ΔH = +277 kJ C + F --> A ΔH = +303 kJ D B --> M ΔH = -158 kJ

*March 21, 2011*

**MATH**

Hello! I am trying to finish a math assignment. it was a bunch of math questions, and I am having a very difficult time with 5 of them. I have the answers to them though. Could somebody please help me with AT LEAST a few!? thanks!! 1) A square swimming pool with a side ...

*March 20, 2011*

**MATH**

Hello! I am trying to finish a math assignment. it was a bunch of math questions, and I am having a very difficult time with 5 of them. I have the answers to them though. Could somebody please help me with AT LEAST a few!? thanks!! 1) A square swimming pool with a side ...

*March 20, 2011*

**algebra**

Perform the indicated operation 1/3divided by 3/8

*March 16, 2011*

**maths exponential functions**

I have a maths assignment and i need help with this question my teacher is overseas at the moment and it is due when he gets back The Population P, of penguins in a certain region of Antarctica can be modeled by the relation P=Po (2) t/90, where t is time, measured in months ...

*March 11, 2011*

**physics**

A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 270 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +2.9 m/s relative to the shore, and then hops onto an identical floating log that is ...

*March 9, 2011*

**Geometry**

Find the volume of a sphere whose surface area is 804 u2

*March 7, 2011*

**Math**

How far does the bike go on one rotation of the pedal sprocket in gear 2c? Gear 2c = 1.95

*March 7, 2011*

** Trig**

Yeah sorry wasn't thinking when I posted that.

*March 6, 2011*

** Trig**

If = 58° and m = 120 in, what is the value of n to the nearest tenth of an inch?

*March 6, 2011*

**precalculus**

An investment decreases by 4% per year for 3 years. By what total percent does it decrease after the 3 years?

*March 3, 2011*