Saturday

February 28, 2015

February 28, 2015

Total # Posts: 1,733

**Chemistry**

K1 = 0.727 K2 = 12.1 T1 = 2000 T2 = 3000 Solve for the standard enthalpy of formation. They gave me the formula ln(K2/K1) = DeltaH /R (T2 - T1 / T1T2) The answer is supposed to be in KJ/mol and I keep getting 2.022 but its not right. I'm not sure what Im doing wrong
*March 24, 2013*

**math**

For the function f(p) an input of 3 yields an output value of 6. What value of p would you use to have f(5p) = 6?
*March 22, 2013*

**Chemistry**

A 50.0 mL sample of 0.10 M pyridine, C5H5N, is titrated with 0.2 M HBr. Calculate the pH to one decimal place when the following volumes of titrant have been added. 0.00 mL a) 0ml b)17ml c)25ml d)40ml
*March 7, 2013*

**math**

6^(2log(x)) = 8
*March 5, 2013*

**math**

Let 2^a = 5 and 2^b = 10. Using exponent rules, solve the equation in terms of a and b. 10^x =(1/64)
*March 3, 2013*

**statistics**

In a certain region, the mean annual salary for plumbers is $51,000. Let x be a random variable that represents a plumber's salary. Assume the standard deviation is $1300. If a random sample of 100 plumbers is selected, what is the probability that the sample mean is ...
*February 25, 2013*

**statistics**

the breaking distance of a Honda CRV can be approximated by a normal distribution, where the mean is 53 meters and the standard deviation is 3.8 meters. Let x be a random variable that represents a braking distance. Find the probability that a randomly selected braking ...
*February 25, 2013*

**P Value Math Statistics**

Find the P-value for the indicated hypothesis test with the given standardized test statistics, z. Decide whether to reject H0 for the given level of significance a. two-tailed test with test statistic z= -1.57 and a=0.04
*February 24, 2013*

**statistics**

In a normal distribution with mu = 25 and sigma = 3, what number corresponds to z = -3? is it 16, 18, or 20
*February 24, 2013*

**Gen Math**

A school dance has 228 students. There are 63 fewer girls than twice as many boys. How many boys and girls attended the dance?
*February 24, 2013*

**Economics**

A $90,000 investment is made. Over a 5 year period, a return of $30,000 occurs at the end of the first year. Each successive year yields a return that is $3,000 less than the previous year's return. If money is worth 5 percent, use a gradient series factor to determine the...
*February 23, 2013*

**Finance**

You plan to open a retirement account. Your employer will match 50 percent of your deposits up to a limit on the match of $2500 per year. You believe the fund will earn 12 percent per year over the next 30 years, and you will make 30 deposits of $5000, plus 50 percent employer...
*February 23, 2013*

**college algebra**

driving along a crowded freeway you notice that it takes a time to go from one mile marker to the next. when you increase your speed by 8.4 mi/hr the time to go one mile decreased by 14 seconds. What was your original speed?
*February 21, 2013*

**Chemistry**

How many grams of solute are present in 875 mL of 0.180 M KBr?
*February 20, 2013*

**Chemistry...**

The oxygen gas emitted from an aquatic plant during photosynthesis is collected over water at a temperature of 25 degrees celsius and a total pressure of 762 torr. What is the partial pressure of the oxygen gas? What formula do I need to use?
*February 20, 2013*

**Need help asap****

Oh goodness. I'm deeply sorry. I wasn't trying to make anyone angry or annoyed.
*February 20, 2013*

**Need help asap** **

The oxygen gas emitted from an aquatic plant during photosynthesis is collected over water at a temperature of 25 degrees celsius and a total pressure of 762 torr. What is the partial pressure of the oxygen gas? What formula do I need to use?
*February 20, 2013*

**report**

thank you
*February 19, 2013*

**report**

What are key findings? I have to include this in a lab report. Thank you for any help
*February 19, 2013*

**Physics **

A plant falls from the windowsill of an apartment in a very tall building. If the floor of your apartment is 12.19 m above the ground, and it takes the plant 0.2580 seconds to cross your 9 ft window, from what height did the plant fall? ? m Explain what would be different if ...
*February 19, 2013*

**math**

14=2/3(9y-15)
*February 18, 2013*

**science**

How do I make an acrostic that has to do with the word Wavelength?
*February 17, 2013*

**Statistics**

These are the only ones that I am having problems with. Please help.. 8.You are given the sample mean and the sample standard deviation. Use this information to construct the 90% and the 95% confidence intervals for the population mean. Interpret the results and compare the ...
*February 17, 2013*

**Chemistry**

On a 10.5 ounce bag of potato chips, the manufacturer states that the single serving is one ounce, which is equivalent to 150 calories. How many kilojoules are in this bag of potato chips? Is it 6.5898kJ?
*February 9, 2013*

**Chemistry**

Ooops, sorry Linda.
*February 9, 2013*

**Chemistry**

On a 10.5 ounce bag of potato chips, the manufacturer states that the single serving is one ounce, which is equivalent to 150 calories. How many kilojoules are in this bag of potato chips? Is it 6.898 kJ?
*February 9, 2013*

**science **

Newton’s Second Law of Motion is expressed as F = ma. If you are pushing a lawn mower in your backyard and suddenly double the pushing force, what will happen to the lawn mower's rate of acceleration? The mass of the lawn mower is constant. A. The acceleration will ...
*February 8, 2013*

**math**

Jill is correct because angels is on any shape
*February 5, 2013*

**math**

thanks
*February 5, 2013*

**math**

I got (9,28) is that right.
*February 5, 2013*

**math **

solve using substitution y=4x-8 y=2x+10
*February 5, 2013*

**Physics**

According to Anna, on Earth, Bob is on a spaceship moving at 0.8c towards Earth, and Carl, a little farther out, is on a spaceship moving a 0.9c towards Earth. According to Bob, how fast is Carl moving relative to Earth? (a) According to Bob, how fast and in what direction is ...
*February 4, 2013*

**social studies**

Which of the following types of information are people LEAST comfortable revealing to professionals? a. emotional b. financial c. legal d. medical
*February 4, 2013*

**Chemistry 3A**

You want to make the following buffer: 5% glucose, 100 mM tris and 10 mM EDTA in a final voume of 300ml. Your stock solutions are 20% glucose, 1M tris and 0.5M EDTA. The diluent is distilled water. Determine how much of each you will add to make the desired buffer. I know this...
*February 1, 2013*

**Math**

Calculate how long a de-orbit burn must last in minutes and seconds to achieve the Shuttle’s change in altitude from 205 miles to 60 miles at perigee.Use the equations and conversions provided below in method 1 or method 2 to find the required burn time
*February 1, 2013*

**penn foster**

im trying to finish these classes soon so i can start college, but honestly they are too complex. and i NEED HELP!!!! I have 1-5 done. 6. In the Mongol Empire, the plague A. provided new oppurtunities for territorial expansion B.ended further expansion C. had no effect, ...
*January 30, 2013*

**physics**

Bob and Bob Jr. stand at open doorways at opposite ends of an airplane hangar 25 m long. Anna owns a spaceship, 40 m long as it sits on the runway. Anna takes off in her spaceship, then swoops through the hangar at constant velocity. At precisely time zero on both Bob's ...
*January 30, 2013*

**Physics**

Bob and Bob Jr. stand at open doorways at opposite ends of an airplane hangar 25 m long. Anna owns a spaceship, 40 m long as it sits on the runway. Anna takes off in her spaceship, then swoops through the hangar at constant velocity. At precisely time zero on both Bob's ...
*January 29, 2013*

**College Algebra**

V= 4/322/7r^ 3 v= 4/3 *22/7*(6 1/4 in)^3 v=3/4 * 22/7 * 15625/64 v= 1023.065476 how to change to a mix-number?
*January 27, 2013*

**College Algebra**

I like to change this(1023.065476) whole number into a mix-number to find the volume of the sphere (6 1/4 in) using 22/7 for pie.
*January 27, 2013*

**geometry**

if measure of angle SUT=3x+6 and measure of angle RUS=5x-4, find measure of angle SUT
*January 27, 2013*

**science **

Lipids: Not a polymer because _ __x's energy than carbs Saturated= Unsaturated= Nucleic Acids: RNA= DNA= Carbohydrates: Building blockks
*January 26, 2013*

**science**

I think it's about 20.
*January 26, 2013*

**science**

How many amino acids are there in protien
*January 26, 2013*

**Math**

I am a 4digits number with 6 hundreds and 5ones.The sum of all my digits is 15 .What number am I
*January 25, 2013*

**Math 7A**

Use the function rule, y = 2x + 5, to find the values of y when x = 1, 2, 3, and 4. Write the answers as ordered pairs that would be used to graph the function. can someone help me i'm stuck on this question
*January 21, 2013*

**alg/trig**

The first thing you want to do is get rid of x in the denominator, because that simplifies things quite a bit. Think of the easiest common denominator between 9/x and 9/(x-2), which would be x(x-2). You know that x-2/x-2 = 1, regardless of the value of x; the same with x/x, so...
*January 21, 2013*

**Math**

10^5.4 = 251188.6432 = 2.5 X 10^5 You can just plug this in the calculator. I think it's two significant figures
*January 21, 2013*

**Physics**

t(Earth) = t(satellite) / (square root) 1 - (v/c)^2 = t(satellite) / (square root) 1 - [ (3.9 x 10^3) / (3x 10^8)^2 ] = (1 - 1.7 x 10^-10)^ - 1/2 [ t(satellite) ] t(Earth) = (1 + 8.5 x 10^-11) [ t(satellite) ] GMEarth = (6.67 x 10^-11 N x m^2/kg^2) (5.98 x 10^24 kg) = 4.0 x 10...
*January 21, 2013*

**Physics**

A GPS satellite orbits at an altitude of 2.0 x 10^7 m and a speed of 3.9 x 10^3 m/s, Earth’s radius is 6.4 x 10^6 m, and a point at its equator has tangential speed of 460 m/s, By approximately what fraction must the time be adjusted to account for both regular/speed-...
*January 21, 2013*

**Math**

7 snow days divide by the the amount of days in december which is 31 days (7/31) x 100 = 22.5 %
*January 21, 2013*

**math **

How would I write 2 inequalities that describe in basketball that 2 points = field goal and 1 point = free throw and I have scored at least 3 points in every game this season and 15 points for the most points in one game? Please Explain! I don't understand.
*January 21, 2013*

**Math**

Use the function rule, y = 2x + 5, to find the values of y when x = 1, 2, 3, and 4. Write the answers as ordered pairs that would be used to graph the function.
*January 18, 2013*

**Physics**

thank you
*January 18, 2013*

**Physics**

The kinetic energy of a proton is half its internal energy. What is the proton's speed? Kinetic energy is (Yu - 1) (mp) (c)^2 = 1/2 (mp) (c)^2 Yu = 1.5 Yu = 1/(square root) 1 - (u/c)^2 1/(square root) 1 - (u/c)^2 = 1.5 u= 0.745c How do I solve for u? I'm extremely ...
*January 18, 2013*

**trig proofs**

cotx+tanx=secx+cscx
*January 15, 2013*

**Math**

Number Sense How can you use 4 x 7 to find 8 x 7? Find the product.
*January 8, 2013*

**Calculus II**

ok thank you very much. Happy New Year
*December 30, 2012*

**Calculus II**

Find x and dx using trigonometric substitution of (integral) square root of 4x^2 - 9 divide by x x = 2/3 sec x dx = 2/3 tan x dx Is this right so far?
*December 30, 2012*

**Calculus II**

ok, thank you very much. Happy New Year
*December 30, 2012*

**Calculus II**

Okay then, is this the final answer = (5-x)(3e^3x) + (integral) -- (1/3)e^3x = (5-x)(3e^3x) + (1/9)e^3x + C
*December 30, 2012*

**Calculus II**

Integrate using integration by parts (integral) (5-x) e^3x u = 5-x du = -dx dv = e^3x v = 3e^3x I wonder if this is right so far. = uv - (integral) v du = (5-x)(3e^3x) - (integral) (-3e^3x) =(5-x)(3e^3x) + (integral) (3e^3x) = (5-x)(3e^3x) + 9e^3x + C
*December 30, 2012*

**Chemistry**

Question: A solution of Silver nitrate, AgNO3, contains 1.08 grams in 250 cm3. What is its molarity? Solution: Molar mass of Silver nitrate = 108 g/mole. n(AgNO3) = 1.08 grams of AgNO3 x 1 mole of AgNO3108 grams AgNO3 = 0.01 mole. Number of moles in 1 dm3 = 0.01 mole x 1000/...
*December 30, 2012*

**Physics**

11 4 n + B ----> ___?___ + He 2 7 8 A. Li or B. Li 235 4 Pa ------> ___?___ + He 91 2 A.230 or B. 231 Ac Ac
*December 18, 2012*

**math**

the expression a^2(b^3)/a^-4(b^2) is equivalent to 1 a^6/b^5 2. b^5/a^6 3. a^2/b 4. a^-2(b^-1)
*December 18, 2012*

**Physics**

A car and a bus are moving down a hill, the bus is 3X heavier than the car and the speed of the car is 3X faster than the bus. Compare their momentum and K.E.
*December 17, 2012*

**Physics**

Who originally designed the planetary model of an atom? Bohr or Rutherford
*December 17, 2012*

**physics**

Maxwell's equations proved that a. Light is a mechanical phenomena b. Light is a chemical phenomena c. Light is a phenomenal phenomena d. Light is an electromagnetic phenomena I think the answer is either a or d. But I'm pretty sure its d Thank you for any help and ...
*December 16, 2012*

**8th Grade English**

My teacher for my english class at school marked off for these questions and said I could redo it and turn it in tomorrow. I am for sure I did these right. Here are the questions. Underline the verb in the parentheses that agrees with the subject. 1. In the Northern Hemisphere...
*December 11, 2012*

**Physics, asap please**

If a sphere and paper are dropped from 10 meters and the sphere hit the ground in 1.4 seconds and the paper hit in 2 seconds, why did the impact time in case of the piece of paper change in comparison to the sphere? A. a=(Wt-R)/m;a=g B. a=(Wt-R)/m;a>g C. a=(Wt-R);a<g D. ...
*December 10, 2012*

**Science **

What is the Mass number and Atomic number for the element B (Boron)? It is for a homework sheet and I am blanked out. I forgot my text book. Can anyone help me?
*December 10, 2012*

**Chemistry 3A**

You have three moles of oxygen and hydrogen. And 1 mol of aluminum as well as one mole of aluminum hydroxide
*December 10, 2012*

**Chem**

PV = nRT - Change pressure to atm - Change grams of oxygen to mol of oxygen for n - Change degrees in celsius to kelvin which in this case is 273 K. Write all of the units of P, n, R and T and it will cancel out to get liters for volume
*December 10, 2012*

**Physics**

If a sphere and paper are dropped from 10 meters and the sphere hit the ground in 1.4 seconds and the paper hit in 2 seconds, why did the impact time in case of the piece of paper change in comparison to the sphere? A. a=(Wt-R)/m;a=g B. a=(Wt-R)/m;a>g C. a=(Wt-R);a<g D. ...
*December 10, 2012*

**Physics**

If a sphere and paper are dropped from 10 meters and the sphere hit the ground in 1.4 seconds and the paper hit in 2 seconds, why did the impact time in case of the piece of paper change in comparison to the sphere? A. a=(Wt-R)/m;a=g B. a=(Wt-R)/m;a>g C. a=(Wt-R);a<g D. ...
*December 9, 2012*

**Physics**

Pretend the hot brick extracts heat from the cold brick and becomes hotter. Would this violate the Law of Conservation of Energy?
*December 9, 2012*

**Physics**

If a sphere and paper are dropped from 10 meters and the sphere hit the ground in 1.4 seconds and the paper hit in 2 seconds, why did the impact time in case of the piece of paper change in comparison to the sphere? A. a=(Wt-R)/m;a=g B. a=(Wt-R)/m;a>g C. a=(Wt-R);a<g D. ...
*December 9, 2012*

**Physics**

A rapidly changing magnetic field in any region of space induces a rapidly changing A.Magnetic field or B.Electric field? which in turn induces a rapidly changing A.Magnetic field B.Electric field?
*December 8, 2012*

**Physics**

If your own mass is 70kg and the mass of a building is 4x 10^6kg and the distance between you and the building is 1m, in comparison to your own weight, estimate the force of attraction between you and the building.
*December 8, 2012*

**Physics**

A car weighing one ton is moving at 50km/hr and a truck weighing two tons is moving at 25km/hr. Both are moving in the opposite direction, which has more momentum? I think they are the same, but want to make sure
*December 8, 2012*

**Physics**

While stationary on a boat you are measuring the time it takes for the coin to leave your hand and hit the water.In order to measure that time you are tuned to the sound of the coin hitting the water. You know that it takes 5.5 seconds for the coin to leave your hand and hit ...
*December 8, 2012*

**Physics**

If one drops a sphere and a piece of paper from the same height of 10 meters(H=10m) and the sphere hits the ground in 1.4 secs and the paper in 2 secs, what is the gravity associated with the sphere and why did the impact time change between the paper and sphere?
*December 8, 2012*

**physics**

.436
*December 6, 2012*

**social studies**

what is the question to usa studies weekly 9
*December 4, 2012*

**science**

What does it mean to be a successful organism? Is bacteria the most successful organisms on earth?
*November 29, 2012*

**College Physics 1**

.767s
*November 28, 2012*

**ENGLISH**

hi ive been reading a book called, the berlin boxing club, and one of my hw assignments say i need to find 10 quotes in the book and im having trouble finding them. can u please help me? :)
*November 27, 2012*

**english**

hi ive been reading a book called, the berlin boxing club, and one of my hw assignments say i need to find 10 quotes in the book and im having trouble finding them. can u please help me? :)
*November 27, 2012*

**College Physics**

Suppose a planet is discovered that has the same total mass as the Earth, but half its radius. Calculate the acceleration due to gravity on the surface of this planet.
*November 27, 2012*

**physics**

The range of human hearing extends from approxmately 20 HZ to 20 000 HZ. Find the wavelenghts of these extremes when the speed of sound in air is equal to 343 m/s. A dolphin is 25 degrees C sea water emits a sound directed toward the bottom of the ocean 150 m below. How much ...
*November 21, 2012*

**algebra**

are you factoring? we are doing that right now if you need help
*November 21, 2012*

**social studies**

what religion was part of the Song Dynasty ?
*November 18, 2012*

**reading**

"It's raining cats and dogs" is an idiom for "it's raining really hard."
*November 8, 2012*

**Physics**

A 60 mm mortar round is capable of being launched at 540 km/hr. If a target is located at a distance of 0.6 km and the mortar takes 7.5 s to reach the target, at what angle must the launcher be set to hit the target?
*November 7, 2012*

**precal**

We have to use the equation f(x+Δ)-f(x) ----------- Δx
*November 6, 2012*

**precal**

Find the Difference quotient: 4/(x-3)^2
*November 6, 2012*

**algebra**

Writing an equation in standard form is good for using the quadratic formula, because it has A, B, and C. I hope that helps :)
*November 5, 2012*

**AP Chemistry**

A 2.50 L balloon is filled with helium gas at sea level, 1.00 atm and 32 degrees celsius. The balloon is released and it rises to an altitude of 30,000 ft. If the pressure at this altitude is 228 mm Hg and the temperature is -44 degrees celsius, what is the volume of the balloon?
*November 1, 2012*

**7th grade math Ms. Sue please!**

I need help with this too! Math is hard for me right now...
*October 30, 2012*

**chemistry**

To what volume must 25.0mL of 18.0M H2SO4 be diluted to produce 1.50 M H2SO4?
*October 28, 2012*

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