1. Chemistry- college

The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta

2. PHYSICS

The observation deck of tall skyscraper 370 m above the street. Determine the time required for a penny to free fall from the deck to the street below.

3. calculus

With x people on board, a South African airline makes a profit of (1104 − 3 x) rands per person for a specific flight. A. How many people would the airline prefer to have on board? Answer: x= B. What is the maximum number of passengers that can board

4. Chemistry

A chemist wants to make 4.5 L of a 0.310 M CaCl2 solution what mass of CaCl2 (in g) should the chemist use

5. Physics

1. Gunter, the weightlifter, can lift a 230.0 kg barbell overhead on Earth. The acceleration due to gravity on the sun is 274 m/s2. 2. a. Would the barbells be heavier on the sun or on the Earth. heavier on the sun b. How much (in Newtons) would the

6. Physics

As Alan is taking a shower, the soap falls out of the dish and Alan steps on it with a force of 500 N. If Alan slides forward and the frictional force between the soap and the tub is 50 N, what is the coefficient of friction between these two surfaces?

7. Chemistry

If 4.0 L of a 4.8 M SrCl2 solution is diluted to 50 L , what is the molarity of the diluted solution?

8. physics

The average human has a density of 940 kg/m3 after inhaling and 1028 kg/m3 after exhaling. (a) Without making any swimming movements, what percentage of the human body would be above the surface in the Dead Sea (a lake with a water density of about 1230

9. chemistry

What volume of HCl gas is produced by the reaction of 2.4 liters of H2 gas with 1.5 liters of Cl2 gas? (Volumes are at the same T and P.) 1. 3.0 liters 2. 4.8 liters 3. 0.75 liters 4. 2.4 liters 5. 1.5 liters

10. Chemistry

2 B5H9(l)+12 O2(g)---->5 B2O3(s)+9 H2O(l) Calculate the kilojoules of heat released per gram (kJ/g) of the compound reacted with oxygen. The standard enthalpy of formations of B5H9(l), B2O3(s), and H2O(l) are 42.84, -1271.94, and -285.83 kJ/mol,

11. Physics

A 87 g arrow is fired from a bow whose string exerts an average force of 105 N on the arrow over a distance of 76 cm. 1. What is the speed of the arrow as it leaves the bow?

12. Economics

Indicate the effect that each of the following conditions will have on a company's average variable cost (AVC) and average total cost (ATC) curves: a. The movement of a company's administrative offices from New York City to New Jersey where rent costs are

13. physics

a 1250 kg car is pulling a 325 kb trailer. The car and trailer have an acceleration of 2,15m/sec2 together. Determine the net force on the ca-trailer combination. What is the net force on the railer?

14. physics

A uniformly charged insulating rod of length 13.0 cm is bent into the shape of a semicircle as shown in the figure below. The rod has a total charge of -7.50 µC. Find the magnitude and direction of the electric field at O, the center of the semicircle.

15. chem

What would be the reaction between Mn2+ and NH3? is it Mn(NH3)? and would this solution react with HNO3, considering it would already have NO3 in it?

16. physics

What is the approximate mass of air in a living room 6.0 m times 3.9 m times 2.7 m?

17. Physics

A baseball is popped straight up into the air and has a hang-time of 6.25 s. Determine the height to which the ball rises before it reaches its peak.

18. Chemistry

The hydroxyl radical (OH) is an important oxidizing agent in the atmosphere. At 298 K the rate constant for the reaction of OH with benzene is 1.24 10-12 cm3 molecule -1 s -1. Calculate the value of the rate constant in L mol -1 s -1. This is what I tried:

19. Physics

A novice skier, starting from rest, slides down a frictionless 35.0 degree incline whose vertical height is 140 m. 1. How fast is she going when she reaches the bottom?

20. Chemistry

For the reaction shown, compute the theoretical yield of the product (in grams) Ti(s)+2Fe(g) = TiF2(s) 6.0 g Ti, 6.0g F2

21. Physics

An Alaskan rescue plane drops a package of emergency rations to a stranded party of explorers. The plane is traveling horizontally at 40.0 m/s at a height of 100 m above the ground. a) How far horizontally from the dropping point does the package strike

22. chemistry

Calculate the solubility (in grams per 100 mL of solution) of magnesium hydroxide in a solution buffered at pH = 12. I can get the answer in grams per mole, but i am having difficulty changing it to g/100ml.

23. Physics

A 150-g block on the end of a spring with a spring constant of 35N/m is pulled aside 25 cm and released from rest. In the electrical analog the maximum charge on the capacitor is 0.25 C. The maximum current in the LC circuit is:

24. ph

A spring (70 {\rm N/m}) has an equilibrium length of 1.00 {\rm m}. The spring is compressed to a length of 0.50 {\rm m} and a mass of 2.1 {\rm kg} is placed at its free end on a frictionless slope which makes an angle of 41 ^\circ with respect to the

25. Chemistry

Calculate the energy difference (E) for the transition from n = 1 to n = 6 energy levels of hydrogen per 1 mol of H atoms. (Report your answer to at least 3 significant figures.)

26. chemistry

Two gases are contained in gas bulbs connected by a valve. Gas A is present in a 56 L bulb at a pressure of 213 torr. Gas B exerts a pressure of 683 torr in a 74 L bulb. What is the partial pressure of gas B after they equilibrate once the valve has been

27. Physics

A father (mF = 83 kg) and his daughter (mD= 43 kg) stand on a flat frozen lake of negligible friction. They hold a 13 m long rope stretched between them. The father and daughter then pull the rope to bring them together. If the father is initially standing

28. chemistry

A sample of an unknown gas effuses in 11.5 min. An equal volume of H2 in the same apparatus at the same temperature and pressure effuses in 2.77 min. What is the molar mass of the unknown gas?

29. chemistry

balance the followig example of a heterogeneous equilibrium and write its reaction quotient, Qc: S8 + F2=SF6 i've balanced it i think i got S8 +24F2 =8SF6 but when i try it it keeps telling me that i'm wrong when i write out the Qc

30. Physics

A spring has a spring stiffness constant, k, of 420 N/m . 1. How much must this spring be stretched to store 30 J of potential energy?

31. algebra

two investments were made totaling $15,000. for a certain year these investments yielded$1432 in simple interest. part of the $15,000 was invested at 9% and part at 10%. find the amount invested at each rate. a total of$1150 was invested, part of it at

32. chem 30

how do you find solubility of Pb(NO3)2, PbCl2, PbCrO4, and PbS

33. ph

A spring (70 {\rm N/m}) has an equilibrium length of 1.00 {\rm m}. The spring is compressed to a length of 0.50 {\rm m} and a mass of 2.1 {\rm kg} is placed at its free end on a frictionless slope which makes an angle of 41 ^\circ with respect to the

The factory wants you to build a box that will hold twice as many cubes.What are the dimensions of a box that contains two times as many cubes as a box that is 2 by 3 by 4 ? W rite the dimensions and explain how you found your answer.

35. physics

A freight train has a mass of 5 x 107 kg. If the locomotive can exert a constant pull of 12 x 105 N, how long would it take to increase the speed of the train from rest to 85 km/h

148. hum 105

a scholarly article that discusses some aspect of the Female Divine in contemporary culture. (This might range anywhere from discussions on goddesses in advertising found in an article on marketing to discussions of feminine principles in contemporary

149. math

Have 2 questions: 1. Factor Trinomial competely x^2 + 8x + 53 (reads as x squared plus 8x plus 53) I am thinking it is prime. 2. Solve 4x^2 + 23x - 30=0 (reads 4x squared plus 23x minus 30 equals zero

150. algebra

state the domain of the function. identify all intercepts and find vertical and horizontal asymtodes. f(x)=x-2 over x+1 or x-2 f(x)= ___ x+1

151. physicss

What average force is required to stop an 1100 kg car in 9.1 s if it is traveling at 83 km/h?

152. Richter scale question

An earthquake registers 6.1 on the richter scale. What is the rating on an earthquake twice as powerful? I know: M=I/Io Then what do you do?

153. English

What is the subject and predicate of. Bloomers were the first slacks for women. Subject Bloomers predicate were the first slack? These pants were very loose and comfortable. Subject pants predicate loose comfortable?

154. calculus

find the sum ∑(n/(n+1)!) from n=1 to infinity

155. Chemistry

For Carbon dioxide, for a volume of 500 mL and temperature of 100 degrees celcius, calculate the pressures using the ideal gas law and the van der Waals equation. Explain any dicrepancies in the calculated values. Ideal Gas Equation: Van Der Waals Equation

156. HIT 105 research paper

I am doing a paper on HIPAA and I need to cite my work. Have the paper finished but I am having problems citing my work. Could someone help me please?

157. Pre Calc.

Use limits to describe the behavior of the rational function near the indicated asymptote f(x)=3/x-4

158. Science

how do you find the degrees for a pie graph (ex) 1st 19 2nd 15 3rd 20 4th 15 5th 22 6th 15 ??? plz help!

259. English

People grow one year older every New Year's Day by eating rice cakes. (What is the meaning of 'grow' in this sentence? What other words can we use instead of 'grow'?)

260. Chemistry

Discuss the formation of the nickel ion with a 2+ oxidation number.

261. Organic Chemistry

acetic acid and isopentyl alcohol form isopentyl acetate and water The excess reagent is acetic acid, and the limiting reagent is isopentyl alcohol. How great is the molar excess (how many times greater)?

262. chemistry

Determine (a) the total number of Cl atoms in 125mL of liquid CCl4 (d= 1.589g/mL) and (b) the number of grams of carbon in 215 of sucrose, C12H22O11.

263. English

1. I want to do volunteer work at the Chicago Orphanage. 2. I want to do volunteer at Chicago Orphanage. (Which one is right? Do we have to use 'the'?)

264. Algebra II

I have a question- The range of y = 1/(x-5) is All real Numbers True or False I think it is false because it should be all real numbers except y shouldn't equal 0. Is that correct or don't I understand it-Please explain if I'm wrong. Thanks

265. statistics

Looking for help with some of my stats homework, I got parts of it but then hit a brink wall. Any help would be welcome. A recruiter estimates that if you are hired to work for her company and you put in a full week at the commissioned sales representative

266. english

1 Sentence thesis on Jules Verne "A journey to the center of the earth"?

267. Global science

A population histogram that looks like a triangle ____. It also means A)the population is rapidly expanding. b) the population is stabilizing.C)a clumped population.d)The population is declining.

268. English

Could you please check if the following sentences are all grammatically correct? Thank you. 1) As Coleridge suffered from chronic rheumatism, the doctors prescribed him opium to ease bodily pains and he became addicted to this drug. 2)He distinguished

269. science

what is sparting?

270. statistics

if the mean of a set of data is 23.00 and 10.00 has a z-score of -1.30, then the standard deviation must be?

271. curriculum content

which is the oldest art? A.Dram-theater B. photography C. Dance D. music

272. chem

complete this reaction 2 NaNO3 + ht →

273. physics

Suppose I have a circular metal disk spinning at a constant angular velocity. Now imagine near to, but not in contact with the first disk, I have an identical metal disk spinning at the same angular velocity but in the opposite direction (ie. W1 = -w2) and

274. lee senior

what is -2x+y=-4

275. equation of exp function

What equation has the following features: It has the x-axis as an asymptote and it passes through (0, -1), (-1,-3) and (-2,-9)?

276. statistics

Does the 99 percent confidence interval include the value suggested by the NCAA? Interpret this result.

277. arithmetic

is 1/8 in the simpelest form

278. Maths

What is the answer to the following using sicentific calculator 64-1/6

279. Chemistry

1. What is the pH of the solution created by combining 0.50 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)? with 8.00 mL of the 0.10 M HC2H3O2(aq)? 2. What are the pH values if you take into account that the 8.00 mL of 0.10 M Acid was first

280. eCONOMICS

Explain how an economist could use the slope of the yield curve to analyze the probability that a recession will occur and why the spread may matter.

281. English

How does the Scarlet letter A affect Hester Prynne's personality and her thinking concerning the position of women in society?

282. Stats

If a confidence interval for the mean is 24.8 < ì < 29.6. What is the margin of error?

283. Physics

A 66 kg bungee jumper jumps from a bridge. She is tied to a bungee cord whose unstretched length is 14 m, and falls a total of 34m. 1. Calculate the spring stiffness constant of the bungee cord, assuming Hooke's law applies. 2. Calculate the maximum

284. Physics

Forces of 10.6 N north, 20.8 N east, and 14.3 N south are simultaneously applied to a 3.76 kg mass as it rests on an air table. What is the magnitude of its acceleration?

285. algebra

find all real zeros and their multiplicity of the polynomial function f(x)=5(X-4)squared(x+2)

286. chem

When the question asks for the qualitative pH of NH3, how would I find the answer?

287. Accounting

Can someone please help me with this question and break it down into dummy terms I am struggling in this course. Even if you have solid financials, can you obtain more market share?

288. English

I need to paraphrase the initial part of the Rime of the ancient Mariner by Coleridge. I wonder if you could help me rephrase the description of the storm.Thank you. 1) The bride, as red as a rose, has entered into the all and a group of singers and

289. math

Find the simple interest of#108,000 for 2 years at 1 and the half percent per annum.pls solve

290. psychology

Define sensation and perception. What is the difference between them? Provide an example.

291. chemistry

How do i find the change in the moles gas for a reaction? example MgCO3 = MgO +CO2

292. MAT117

SOLVE ^Y+6-1=4 A) The solution to Y=_ OR B)Solution is not a real number Can't figure this one out... This is what I came up w/ Y=^5

293. Physics- pls help

A 5kg object starts at rest and has a force applied to it of 10 Newtons for 2 seconds, followed by 20 Newtons for 2 seconds, followed by 30 newtons for 2 seconds, all in the same direction. a. Determine its final velocity b. Sketch a graph of force vs time

294. log graph

How do you graph y= -log (base 5)(-x)? The written question is: Sketch above equation by first describing the transformations performed on the equation y= log (base 5)(x) And what is the inverse function? x=log (base 5)(y)?

Thompson assumed that the amount of positive charge and negative charge in an atom was equal. Was this a reasonable assumption? I really do not understand this. I tried looking up on the site, but information there wasn't so clarified.

296. Chemistry

A sample of low-fat margarine is heated and separates into two layers. Identify the top and bottom layers and explain why the top layer rises to the top

297. Tissue box project help?

So, I have to design a tissue box. ( I already bought one) and, It has to be anything related to english, as in ( parts of speech, words, ) anything. anything related to language arts. and I need some ideas? Could somebody help me? Thank you. -Allyson

298. Math

find the sum of arthmetic progression 12,15,18,,,,,, 84, a=12 d=3 n=?

299. science

Animals use the energy found in food to produce _____ and _____.

300. world history

I was wondering how to spell Ida Peeiffer I mean like this lady couldn't even find it on the internet how crazy is that.

301. ethics

What would utilitarianism say about plea bargaining and the death penalty?

302. cell

If the cell do not have membrane; Does it still consider be a cell?

303. MAT117

SOLVE ^Y+6-1=4 A) The solution to Y=_ OR B)Solution is not a real number Can't figure this one out... This is what I came up w/ Y=^5

304. math

find all real zeros and their multiplicity of the polynomial function f(x)=5(x-4)squared(x+2)

305. pre Calc.

Describe the behavior of the function near the vertical asymptote. Is there another way to word this problem so that I might understand? Seriously, I have gotten everything so far, so is this just worded weird?

306. math

how do you find the degree for a octagon

307. Stats

A group of 56 randomly selected students have a mean score of 30.8 and a standard deviation of 4.5 on a placement test. Find a 95% confidence interval for the mean score, ì, of all students taking the test. (Note: ó is unknown.)

Suppose there is a circular metal disk spinning at a constant angular velocity. Now imagine near to, but not in contact with the first disk, there is an identical metal disk spinning at the same angular velocity but in the opposite direction (ie. W1 = -w2)

309. English

I need some ideas of novels,songs,comics etc.(preferebly a song) that share similar views as Transcendentalists Here are some views of the Transcendentalists: -Intuition -they think we can understand ourselves through nature. - Individualism(the fact of

310. Math

what is 3(x)-6(x) show work please

311. journalsim

Have women today been more involved in politics than before? Why or why not?

312. ethics

What are some of the consequences of violating a workplace standard?

313. ethics

What are the consequences of violating a societal norm?

314. Trigonomentry HELP NOW

Rationalize in simplest form: (2ãx + ã8x)/(xã8 + 5)

315. PHYSICS ---HELP!

Suppose there is a circular metal disk spinning at a constant angular velocity. Now imagine near to, but not in contact with the first disk, there is an identical metal disk spinning at the same angular velocity but in the opposite direction (ie. W1 = -w2)

316. Math and science

If a circuit has a 3.9 k ohms resistor and a 5 uF capacitor, find the current flow in the circuit at 0.005 seconds, if the maximum current flow in the circuit is 1.5 mA.

317. spanish

yo bebo mucha agua..is this right?

318. Physics HELP!!! Potentials and Fields

Two identical metal plates with small holes are aligned a distance L=6.7 cm apart. They have a potential difference of 131 Volts. An electron can enter through the hole in the negative plate and exit through the hole in the positive plate. If it enters

319. algebra urgent !!!!

how to get from step 2 to step 3 1. (x^3 + y^3) + xy(x + y) 2. (x + y)(x^2 - xy + y^2) + xy(x + y) 3. (x + y)(x^2 + y^2) objective: factorization

320. Math and science

If a circuit has a 3.9 k omega resistor and a 5 uF capacitor, find the current flow in the circuit at 0.005 seconds, if the maximum current flow in the circuit is 1.5 mA.

321. math

what is the discriminant of the quadratic y= -3x^2 - 4x - 3 also explain what the graph will look like?? thanks

5/9-1/12

323. algebra 1

there are 5 rows of pictures with 3/16 inch of vertical space between pictures.Draw a diagram and label all the heights on your diagram then write and solve an equation to find the height of each picture

324. math

how long would it take for the investment to triple using this equation: A=3200e^(0.062t) and would i solve this

325. ethics

Why do you think employers don't want you to use social networking sites at work? What would be the consequence of dressing inappropriately at your place of work? What would happen if someone did?

326. physics

time down ramp #1=2 sec.,time across table top is 5sec.,time up ramp #2 is 4 sec., distance across table top between ramp is 20 meter long

327. english 3

Came to America to find freedom to worship and the Promised Land

328. Math

I was given this by my teacher for extra credit 1 _ _ _ _ _ 1 _ the blanks are numbers from 0-9 excluding 1 since it was given. I need to know how many possible combinations are left and if there is a good website that will generate all the combinations.

329. Global science

why are so many niches available on recentlydevasted islands

why did us want to buy small part of louisiana territory

331. Math

what exactly is an unequal group?

332. geography

How are Paraguay and Zambia similar? My answer is- Both are surrounded by other countries and both of them are completely under the Equator. Is this correct?

333. scinces

why are so many niches available on recently deastated island?

i have to write an algebraic expression for the following: jasmine has three times as many chores as her younger brother does.

335. English-

I posted earlier but i wanted to added something... I need have to find a song that share similar views as Transcendentalists Here are some views of the Transcendentalists: -Intuition -they think we can understand ourselves through nature. -

336. Physics

Forces of 10.6 N north, 20.8 N east, and 14.3 N south are simultaneously applied to a 3.76 kg mass as it rests on an air table. What is the magnitude of its acceleration?

337. PHYSICS

A bullet is fired horizonatally at a target 100 m away and hits 0.5 m below the target. what is the velocity of the bullet?

338. Maths

if f(x) = 2x - x ln x show that f(e^3) = -e^3 I know you have to substitute e^3 into the function, so Ive sone ths so far: 2e^3 - e^3 ln e^3 What is the next step?

339. 7th MATH

Write an expression to represent the following: "h subtracted from the product of 3 and g". A 3G-H B H-3G C (H-3)G D 3(H-G) From my opinion: Giving it a try would B be the correct answer?

340. graphing

How do you graph y= -log (base 5)(-x)? The written question is: Sketch above equation by first describing the transformations performed on the equation y= log (base 5)(x) And what is the inverse function? x=log (base 5)(y)?

341. fundamentals of accountig

explain clearly the examples of the main items used in the adjusting process

342. problem solving

If a circuit has a 3.9 k ohms resistor and a 5 uF capacitor, find the current flow in the circuit at 0.005 seconds, if the maximum current flow in the circuit is 1.5 mA.

343. Remembrance day

What does this line from the poem Flander's Fields mean? Take up our quarrel with the foe

344. Math

log base 2 (3r+5)= 5

345. math

the area of a rectangle is 60cm.the length is 11cm more than the width. find the width.

346. math

what is the answer to 2/7+3/4=

347. Math

If rs-t=1, what is the value of s? A. r-t+1 B. 1+r/t C. 1-r+t D. 1+t/r /=fraction symbol.

348. Vectors

45cm at 53 degrees

349. log equation graph

How do you graph y= -log (base 5)(-x)? The written question is: Sketch above equation by first describing the transformations performed on the equation y= log (base 5)(x) And what is the inverse function? x=log (base 5)(y)?

350. algebra

f-g/1 = g/1 How can I make g the subject?

351. General Question

How might a potential employer evaluate your writing if you did not use proper verb tenses? Why? General question, I ned others perspective on to help answer this question. thanks

352. sports math

There are many ways to add any numbers 3,5,7,9,11, and 12 to get a sum of 20. Numbers may be repeated.One way to get a sum of 20 is 9+5+3+3. Find four other ways.

353. Maths

if f(x) = 2x - x ln x show that f(e^3) = -e^3 I know you have to substitute e^3 into the function, so Ive sone ths so far: 2e^3 - e^3 ln e^3 What is the next step?

354. geometry

A figue made from seven identical trepezoids is shown. Find the perimeter of the figue.

355. scinces

If a pair of mice is released on an island what might happen ot the population of finches living there?

385. college algebra HELP

The population of a city was 166 thousand at the begining of 2004. The exponential growth rate was 1.5% per year. Use the formula P(t)=P[o]e^(kt) where P[o] is the population in 2004 and k is the exponential growth rate. a) predict the population in 2016,

386. chemistry

What is the purpose statement for the lab comparation titrations?

I don't get how to do this. I'm so lost please help me. Determine the equation of the parabola with roots 2+√3 and 2-√3, and is passing through the point (2,5) this is what i did but its the wrong answer: y= a[x + (2+√3)] [x+(2-√3)] 5= a[2 +

388. Algebra

factor completely 3y^2-27

Can somebody help me solve this problem? Simplify and evaluate the expression for y = 0, z = -1.5. -0.8z +0.005z(-0.001y - 3.1 + (-1.5z + 3))

390. Networking

I was wondering if when I posted my paper, everyone would help me proof it and help me find references, I've done most of it by memory, and what I would do situations, but I need references. If you would that'd be awesome

391. English

Thank you very much for your help. I still ha a few doubts on a few sentences.I hope you can have a look at them, too 1)Tess has heard about Mickey by her friend Storm. Mickey is broke. He’s got a job as a dish washer. He works every evening after school

392. geometry

how many lines of symitery does a delts shape have

393. ap calc bc

hello! what is the derivative e^4 ???? thank you!

394. economics

how would a citizen whoose income is in the top one percent talk about scarcity and trade offs?

395. Global science

Exponential growth is stopped when______equals. there are no choices and I don't hve an answer. I am learning about Growth and population.My science book is called Global science Earth/ environmental systems science by Kendall Hunt publishing company. It