Tuesday

October 21, 2014

October 21, 2014

Total # Posts: 915

**chemistry**

* A 50 gram sample of an unknown metal warms from 18 to 58 after absorbing 800 joules of energy. what is the specific heat of the metal? *copper has a specific heat of 0.387 j/g degree celsius. what is the mass of a piece of copper that undergoes a 21.0 C temperature change ...
*December 11, 2012*

**Math**

2) which set of measure could be the side lengths of a right triangle? A. 0.9 cm, 1.2 cm, 1.5 cm B. 4 in, 4 in, 4 in C. 7 m, 8m, 9m****** D. 2ft, 3ft, 4ft
*December 6, 2012*

**Math**

Sorry meant rational number?
*December 6, 2012*

**Math**

Which of these is an irrational number? A.. Sq root of 14 B. -sq root of 9 C. -sq root of 34 D. Sq root of 72
*December 6, 2012*

**Math**

1) 3r + 5 _____. + 2 = 12-2r 2 Find value of r
*December 6, 2012*

**Chemistry**

The fictitious compound, arrhenium fluoride ( ), reacts with itself to form a dimer with the formula Ah2F2 . The reaction is second order in AhF. The value of the rate constant is 8.591x10-3 M-1s-1. What is the initial rate of reaction in a reactor filled with AhF to a ...
*December 4, 2012*

**PHYSICS**

After 6.00 kg of water at 80.4 oC is mixed in a perfect thermos with 3.00 kg of ice at 0.0 oC, the mixture is allowed to reach equilibrium. When heat is added to or removed from a solid or liquid of mass m and specific heat capacity c, the change in entropy can be shown to be...
*December 1, 2012*

**PHYSICS**

The wattage of a commercial ice maker is 226 W and is the rate at which it does work. The ice maker operates just like a refrigerator and has a coefficient of performance of 3.90. The water going into the unit has a temperature of 15.0°C, and the ice maker produces ice ...
*December 1, 2012*

**CHEMISTRY**

The standard electrode potential for the reduction of Eu3+(aq) to Eu2+(aq) is −0.43 V. determine which of the following is capable of reducing Eu3+(aq) to Eu2+(aq) under standard-state conditions? (a) Sn2+(aq) (b) ln(s) (c) HCN(aq) (d) La(s)
*November 30, 2012*

**statistics**

Working on "Inferences from Dependent Samples" trying to find the standard deviation of the difference data. Differences: 24, 53, 100, 40, -10,71,77,70, 39, 50 n=10 d=51.4 sd=??? (Answer suppose to be 30.8336 but not coming close to this number at all)
*November 30, 2012*

**CHEMISTRY**

Co(s) will oxidize Fe(s) while leaving Cu(s) unreacted, please write a balanced equation for the reagent involved?
*November 30, 2012*

**chem **

A 0.01020 mg sample of an unknown compound was found to contain 0.0084 mg of C, and 0.0018 mg of H. It was also determined that the unknown compound had a molecular weight of 58.12 g/mol. What is the molecular formula for this compound?
*November 29, 2012*

**Math**

Sorry I repeated these question to you because I forgot to add there are repeating numbers or ellipsis.
*November 29, 2012*

**Math .. Please help Reiny**

Reiny, do u think 1st question about blankets should b written differently? For e.g. If we say b= 5, then the first part of the equation will equal 175+ 5= 80. I'm thinking it should be written as this: 25 (7+b) = 300 175 + 25b = 300 25b = 125 Pls let me know what you ...
*November 29, 2012*

**CHEMISTRY HWK MAKES NO SENSE **

How many grams of C are required to make 464.99 grams of this compound? compound= C3H8
*November 29, 2012*

**Math**

Reiny ...Thank you so much for your helpfulness and kindness. Goodnight...
*November 29, 2012*

**Math**

Ok.. Can u check these for me too please? Rename each repeating decimal as a fraction in lowest terms. Using let statement, an equation, a proper solution (using properties of equality) 1) 0.87 (repeating nos are 87) So.. Let X = 0.87 100X = 87.87 - &...
*November 29, 2012*

**Math**

I know, but wanted to be sure about the let statement, equation parts they were asking for. Thanks.
*November 29, 2012*

**Math**

Tickets to King Middle School play cost $1 for King students and $3 for everyone else. Rose, a student at King Middle School, went to the play with friends from another school. the group paid a total of $13 for the tickets. How many friends went to see the play with Rose? ...
*November 29, 2012*

**math**

please help, I'm having a hard time set up the problem. Thank you Sally drove a distance of 520 mile. Had she averaged 15mph faster, the trip would of taken 2.4 hours less. find the average speed that she drove.
*October 29, 2012*

**algebra**

Sally drove a distance of 520 mile. Had she averaged 15mph faster, the trip would of taken 2.4 hours less. find the average speed that she drove.
*October 29, 2012*

**physics**

A light of ray is incident at an angle of 58degrees on the plane surface of a block of glass of refractive index 1.60. Some light is reflected on the other side of the normal att he same angle as the angle of incidence. Find: a.the angle between the light reflected from the ...
*October 24, 2012*

**Algebra**

Year, t Sales, S(t) 1 62 2 246 3 664 4 1579 5 3258 6 8430 7 14,532 (c) If S−1 exists, find S−1(3,258).
*October 24, 2012*

**physics**

State the surface powers required to produce the following lenses with +6.25D front curves. a. -0.50 DS b. +0.50 DS c. +1.75 DS Is a -6.75DS?....
*October 23, 2012*

**physics**

is a =-6.75DS?...
*October 23, 2012*

**physics**

state the surface powers required to produce the following lenses with +6.25D front curves. a. -0.50 DS 6. +0.50 DS c. +1.75 DS
*October 23, 2012*

**Discrete Mathematics**

okay ive got the answer as 2*389-3.5*222 but i done it with trial an error with random numbers, dont no the actual formula
*October 20, 2012*

**Discrete Mathematics**

ive got 389 = 1*222 +167 then 222= 1*167 +55 167= 3*55 +2 55= 27*2 +1 2= 2*1 and hence 1 = GCD of (389,222) but im not sure how you work out the a,b values??
*October 20, 2012*

**Physics**

help
*October 20, 2012*

**math **

why isnt anybody answering my questiions? do u have to have an account or something? if you do just tell me and ill get one!!!1 because everybody else has an answer! you should at least tell me that i need an account if i do!
*October 14, 2012*

**physics**

Snowballs are thrown with a speed of 12.5 m/s from a roof 7.8 m above the ground. Snowball A is thrown straight downward; snowball B is thrown in a direction 16° above the horizontal. (a) Is the landing speed of snowball A greater than, less than, or the same as the ...
*October 12, 2012*

**physics**

In a game of basketball, a forward makes a bounce pass to the center. The ball is thrown with an initial speed of 3.1 m/s at an angle of 15.0° below the horizontal. It is released 0.82 m above the floor. What horizontal distance does the ball cover before bouncing? Please ...
*October 12, 2012*

**Physics**

Vector Aarrowbold points in the negative y direction and has a magnitude of 8 units. Vector Barrowbold has the same the magnitude and points in the positive x direction. Find the direction and magnitude of the following vectors. a) Aarrowbold + Barrowbold magnitude direction &...
*October 12, 2012*

**Chemistry**

what are redox/non-redox not getting it? Can you break it down?
*October 12, 2012*

**Chemistry**

how do you balance equations to get the formula?
*October 11, 2012*

**Chemistry**

How many moles of H2 can be produced? (2.14 mol)
*October 11, 2012*

**statistics**

The heights of women aged 20 to 29 follow approximately the N (64, 4) distribution. Men the same age have heights distributed as N (69.8, 1.1). What percent of young women are taller than the mean height of young men?
*October 10, 2012*

**Chem**

Zinc, copper, lead, and mercury ions are toxic to Atlantic salmon at concentrations of 6.42 times 10 to the -2 mM, 7.16 times 10 to the -3 mM, 0.965 mM, and 5.00 times 10 to the -2 mM, respectively. What are the corresponding concentration is milligrams per liter? A. ...
*October 1, 2012*

**Math grade 7**

thx
*September 10, 2012*

**Math grade 7**

The number 7 is a factor of 1001. explain how you know 1001 is a multiple of 7? How does knowing that 7 is a factor of 1001 help you to get another factor of 1001?
*September 10, 2012*

**math**

1. Divide. Write your answer in simplest form. 2/3 / 1/4 2. Find the product. 1/2 x 3/7 3. Divide. Write the quotient in simplest form. 3/5 / 2/10 4. Divide. Write the quotient in simplest form. 3/4 / 4/5 plz help me
*August 31, 2012*

**lang arts**

on number two the sentence is the first one
*August 31, 2012*

**lang arts**

1. Which sentence describes setting? As much as it saddened her, the first thing Nan had to do was leave her beloved family home. Marcy wanted to go to the dance, but Rob’s treatment of her that day gave her second thoughts. Steve was fairly short, with glasses and dark ...
*August 31, 2012*

**chemistry **

molecules of two different compounds contain the same number of atoms of each element but have different arrangement of atoms. which term correctly describes these two substances? a) isomers b) isotopes c) polymers d) none of the above
*August 27, 2012*

**chemistry **

molecules of two different compounds contain the same number of atoms of each element but have different arrangement of atoms. which term correctly describes these two substances? a) isomers b) isotopes c) polymers d) none of the above
*August 27, 2012*

**chemistry **

the elements of group VII A form ions with a charge of: A) +1 b) -1 c) -2 d) +2 can u please explain too? thankyou
*August 27, 2012*

**physics**

what are convex lenses?
*August 25, 2012*

**writing**

Which of the following does not belong in a conclusion paragraph? A. An attention grabbing sentence. B. A restated thesis sentence. C. A conclusion sentence. D. A summary of supporting details
*August 24, 2012*

**stats**

What does a p value p>0.05 mean? does it mean significant or insignificant? also, what does significant and insignificant mean?
*August 21, 2012*

**Math 1**

In audition for school play, 70% passed the quality of the jurors for the first week. of those remaining, 20% were chosen. if only 7 were qualified, how many tried their luck?
*July 21, 2012*

**math**

Please note, this is one section of the problem. I didn't feel the need to post the entire question as I understand how to do it...minus this one part. (2 tan pi/3) apparently becomes 2 sqrt 3.....explain?
*July 15, 2012*

**Statistics**

A local fire station receives an average of 0.5 rescue calls per day. Find the probability that on a randomly selected day, the fire station will receive fewer than two calls.
*July 13, 2012*

**Reading**

when you are purchasing auto insurance, your agem sex and marital status are considered together as your. A. claims history B. ratung territory C. driving record D. Driver classification I got B but it was WRONG
*July 11, 2012*

**calculus **

Can some explain how to do this problem? I tried using derivatives...but...I keep getting a different answer from what my teacher told me! A projectile is fired directly upward with an initial velocity of 144 ft/sec and its height (in feet) above the ground after t seconds is ...
*July 7, 2012*

**math**

A men's shoe store uses a markup rate of 115% on its most popular brands of shoes. If the shoe store buys a pair of popular-brand shoes for a wholesale price of $79, what will be the retail price of the shoes, to the nearest cent?
*July 6, 2012*

**calculus**

Andddd I just realized to take out the 3 out the 6 and 9 T_T opps. Thanks, now I feel dumb XD
*July 5, 2012*

**calculus**

I took out the 3x which gave me 3x(x+6-9) but if that's wrong...it's wrong :) thanks for the help!
*July 5, 2012*

**calculus **

hey I just wanted to make sure that I was doing this problem correctly. The question says to graph the function f given by f(x)=x^3+3x^2-9x-13 and find the local extremer. So here's what I did: f(x)=x^3+3x^2-9x-13 F^1(x)=3x^2+6x-9 = 3x(x-3) x=0 x=3 I put those two xes back...
*July 5, 2012*

**Algebra 1**

awesome.. I wasnt sure about the negative sign..:)
*June 28, 2012*

**Algebra 1**

can a base be negative at the same time as my exponent? how will you solve this one? -6 ^-3
*June 28, 2012*

**Chemistry **

Tube worms that survive near geothermal vents of hydrogen sulfide rely on bacteria living inside them to obtain energy by the oxidation of H2S to SO4^2-. What is the overall change in the oxidation number of sulfur for this reaction?
*June 26, 2012*

**Algrebra 1**

awesome thank you so much...! :)
*June 26, 2012*

**Algebra**

yes thank you!
*June 26, 2012*

**Algebra**

how to tell the difference between a negative number raised to a power and the opposite of a positive number raised to a power. Use examples in your explanation.
*June 26, 2012*

**Essay**

The supporting details
*June 21, 2012*

**math**

1-1/square root 3
*June 15, 2012*

**math**

I don't understand this question. I am suppose to be simplifying this: u^4-1/u^3-1 I put (u^2+1) (u+1)(u-1) for the top but the bottom, I can't figure out why my book put (u^2+u+1)(u-1) when it's only u^3...where did the extra u come from?
*June 12, 2012*

**statistics**

Which hypothesis-testing procedure would you use in the following situations? • The mean time an American family lives in a particular single-family dwelling is 11.8 years. A sample of 100 families in the Sycamore, OK area shows the mean time living in a single family ...
*May 29, 2012*

**Calculus**

factor fully: x^3 + x^2 - 7x + 2 give n that x=2 is a root
*May 7, 2012*

**Politics**

In Gandhi's account, the person practicing civil disobedience: Openly and civilly breaks an unjust law and quietly suffers the resulting penalty. Must refuse compliance with all of that society's laws for the sake of consistency. Is justified in retaliating against the...
*April 30, 2012*

**child development**

I understand...This lesson is just kicking my butt
*April 24, 2012*

**child development**

Oh okay sorry I just found this side and it is the first time using it but thanks for your help
*April 24, 2012*

**child development**

When both parents believe that men are capable of nurturing infants a. mothers devote time to caregiving b. fathers devote less time to caregiving c. fathers devote more time to caregiving d. the marital relationship tends to suffer, particulary when me spend little time in ...
*April 24, 2012*

**math**

what is the derivative of y=ln(x/4)
*April 10, 2012*

**Identifying a Fallacies**

I can't seem to figure out which fallcy this would be, is anyone familiar and could tell me which one for the following statement? 'To parents who think it's a good idea to share parenting, I say, "OK then, let the child stay in the house and you two swap ...
*April 3, 2012*

**Critical Thinking**

What kind of rhectorical or fallaci is this statement When religious conservatives enact laws to enforce the idea that their God abhors suicide, they threaten the central principle on which America was founded
*April 2, 2012*

**URGENT Spanish help please.**

thank you!
*April 1, 2012*

**URGENT Spanish help please.**

ok in the example it shows: ¿Comprendes espanol? Si, lo comprende ok for this question it's asking 1) do you and your siblings practice tennis my response: no, no los practicamos.. it said i was wrong how would I correct that 2) it asked does your mother teach ...
*April 1, 2012*

**Trig **

Solve the equation 2sin(2x) = cos x. and Solve the equation cos^2(2x)–sin^2(2x)= (√3 / 2).
*April 1, 2012*

**Trig**

Use the half-angle formulas to come up with an exact expression for each function value below. You do not have to simplify your answers. cos(pi/16)
*April 1, 2012*

**trig**

prove: cot^2(x)=cos(x)/(sinx)(tanx)
*March 26, 2012*

**Derivatives**

differentiate and simplify y= (e^x - 1) / x^2
*March 25, 2012*

**math**

I have solved the following questions, let me know if they are correct, thanks. 1. Simplify, and write in the base of 3: (9^x . 3^4x)^2 answer: 3^12x 2. Differentiate and simplify a. y= 3x^4 - 4e^x + 8 answer: 4(3x^3 - e^x) b. y= (3 + 4e^x)^5 answer: 20e^x (3+ 4ex)^4 c. y= (e^...
*March 24, 2012*

**math-check**

I have solved the following questions, let me know if they are correct, thanks. 1. Simplify, and write in the base of 3: (9^x . 3^4x)^2 answer: 3^12x 2. Differentiate and simplify a. y= 3x^4 - 4e^x + 8 answer: 4(3x^3 - e^x) b. y= (3 + 4e^x)^5 answer: 20e^x (3+ 4ex)^4 c. y= (e^...
*March 24, 2012*

**American Literature**

Describe the political role of the poetry of the 1950s? can anyone give a few pointers on this, thanks!
*March 24, 2012*

**trig**

Solve for theta, giving a general formula for all of the solution: tan(theta)=-1 sin(theta/2)=1/2
*March 22, 2012*

**Trig**

4sin^(2)x-3=0
*March 21, 2012*

**physics**

I got frequency: 2pi/√ 2 Period: √2/2pi
*March 21, 2012*

**physics**

What is the period and frequency of a 10-pound weight oscillating (as a pendulum) on a 5-meter-long rope?
*March 21, 2012*

**physics**

consider the following: A point on the tip of a tuning fork vibrates in harmonic motion described by the equation d=10sin(ωt). 1. ω for a tuning fork that has a frequency of 535 vibrations per second. (I don't understand this question) 2. How many cycles does the...
*March 21, 2012*

**trig**

Determine the least positive value of t for which d=0. d=cos((3pi/4)(t)) 0=cos((3pi/4)(t)) I got stuck on this step Please help
*March 21, 2012*

**trig**

Determine the least positive value of t for which d=0. d=cos((3pi/4)(t)) 0=cos((3pi/4)(t)) I got stuck on this step Please help
*March 21, 2012*

**physics**

A buoy oscillates in simple harmonic motion according to the motion of waves at sea. An observer notes that the buoy moves a total of 6 feet from its lowest point to its highest point. The buoy returns to its highest point every 15 seconds. Amplitude: 6 feet Period: ??? ...
*March 21, 2012*

**physics**

How do I find omega (ω)?
*March 21, 2012*

**physics**

Would I use cosine or sine?
*March 21, 2012*

**physics**

A buoy oscillates in simple harmonic motion according to the motion of waves at sea. An observer notes that the buoy moves a total of 6 feet from its lowest point to its highest point. The buoy returns to its highest point every 15 seconds. Amplitude: 6 feet Period: ??? ...
*March 21, 2012*

**chemisrty**

The molar heat capacity of silver is 25.35j/mol C . How much energy would it take to raise the temperature of 9.30 grams of silver by 12.0 C?
*March 20, 2012*

**chemistry**

when I work this out I get 5.7 g but it is saying that my answer is incorrect and I am not sure what I am doing wrong..
*March 19, 2012*

**chemistry**

A 32.2 g iron rod, initially at 22.3 C, is submerged into an unknown mass of water at 63.9 C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 58.6 C. What is the mass of the water?
*March 19, 2012*

**physics!!!**

The index of refraction for crown glass is 1.512 at a wavelength of 660 nm (red), whereas its index of refraction is 1.530 at a wavelength of 410 nm (violet). If both wavelengths are incident on a slab of crown glass at the same angle of incidence, 1.1°, what is the angle ...
*March 19, 2012*

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