Thursday
April 17, 2014

Posts by DC


Total # Posts: 33

physics
A 34-kg girl is bouncing on a trampoline. During a certain interval after leaving the surface of the trampoline, her kinetic energy decreases to 220 J from 480 J. How high does she rise during this interval? Neglect air resistance.

Chemistry
ok I recalculated and got the w=.006523kJ and the energy change to be -76.82kJ... The energy change is right but the w is wrong for some reason... I calculated w as w=-delta(n)RT = -(0-.26312molO2)(8.314452x10^-2 Lbarr/molK)(25+273.15) = 6.5226J=.006523kJ...

Chemistry
ok I recalculated and got the w=.006523kJ and the energy change to be -76.82kJ... The energy change is right but the w is wrong for some reason... I calculated w as w=-delta(n)RT = -(0-.26312molO2)(8.314452x10^-2 Lbarr/molK)(25+273.15) = 6.5226J=.006523kJ...

Chemistry
help - confusion :( The oxidation of copper(I) oxide, Cu2O(s), to copper(II) oxide, CuO(s), is an exothermic process, 2 Cu2O + O2 --> 4CuO The change in enthalpy upon reaction of 75.30 g of Cu2O(s) is -76.83 kJ. Calculate the work, w, and energy change, ΔUrxn, when 75....

Chemistry
I would really appreciate some help with this thermochemistry problem! I'm really confused as to why I keep getting the wrong answers... I have gotten w=-1.305kj and energy change = 78.13kj... both of which were marked wrong. Here's the question: The oxidation of coppe...

Chemistry
Thanks Dr.Bob!! I was then able to plug into the second equation and found the concentration of calcium! You were great help! Thanks again :)

Chemistry
These are the given Ksp values to use: Ksp of Co(OH)2 is 5.9x10^-15 M^3 Ksp of Ca(OH)2 is 5.0x10^-6 M^3

Chemistry
A mineral sample is analyzed for its cobalt and calcium content. A sample is dissolved, and then the cobalt and calcium are precipitated as Co(OH)2(s) and Ca(OH)2(s). At what pH can Co(OH)2(s) be separated from Ca(OH)2(s) at 25 °C? Assume that an effective separation requi...

Chemistry
A canister holds a gas at 16.3 psi when the temperature is 15˚C. To what will the pressure change when the temperature is increased to 20˚C? *

Chemistry
A canister holds a gas at 16.3 psi when the temperature is 15˚C. To what will the pressure change when the temperature is increased to 20˚C? *

Chemistry
10.7 L of a gas at 1.75 atm are expanded to 20.0 L at a constant temperature. What is the new gas pressure? *

Physics
,,,,,,

Math
Thank you Ms. Sue - Happy Holidays to you!

Math
(ACB)24

Math
Twelve people serve on a board and are considering three alternatives: A, B, and C. The choices followed by vote is shown in following table. Determine the winner, if any, using a Borda count. (ABC) 2 (ACB) 4 (BAC) 2 (BCA) 1 (CAB) 2 (CBA) 1 The winner is _____?

Algebra
You're awesome, thank you much and Happy Holidays to you!

Algebra
A club consists of 16 men and 19 women. In how many ways can they choose a president, vice president, treasurer, and secretary, along with an advisory committee of six people? (Round the answer to five decimal places.) _____ x 10(to the 11th power) ways

Algebra
You're awesome, thank you much and Happy Holidays to you!

Algebra
The campus vets club is having a raffle and is selling 2,700 tickets. If the people on your floor of the dorm bought 297 of those tickets, what is the probability that someone on your floor will hold the winning ticket? (Enter your answer as a decimal.)

Algebra
Thank you so much for your response. Just to be clear are you saying I need to multiply .8176 x 80 and then .7977 x 80?

Algebra
Suppose that people's heights (in centimeters) are normally distributed, with a mean of 175 and a standard deviation of 6. We find the heights of 80 people. (a) How many would you expect to be between 167 and 183 cm tall? (b) How many would you expect to be taller than 170...

physics
if i travel in a bus which have 40km/hour speed than i through a coin in vertical hight. Does the coin fall in my hand

living life a health life
what are the three methods by which HIV and AIDS are usually transmitted?

Math
5w=42

college
Evaluate the difference quotient for the given function. Simplify your answer. f(x) = 3 + 5x − x2, f(4 + h) − f(4) h

LIfe orientation
5 ways : Water and sanition , Population

math
(9x^4+0x^3+8x^2+17x-20)÷(-3x-4)

Physics
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Physics
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math
The sum of the page numbers on the facing pages of a book is 457. Find the page numbers?

business
Consider the wide spectrum of business organizations, ranging from gigantic corporations to working at home. Describe at least three types of business organizations that you are familiar with or that you would like to know more about. How is each one advantageous to the busine...

chem
method of producing aspirin

ss
what type of fallacy 12. That's gotta be a great line of clothes. Have you seen the prices and the people endorsing it? 8. Michael Jordan wore that brand, so those must to be the best basketball shoes. (FALSE ANALOGY) 5. All right-thinking people will support the Board of ...

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