Thursday
September 18, 2014

Posts by DC


Total # Posts: 32

geometry
If Dave is 6 feet tall and casts a shadow of 15 feet, what is the height of a tree that casts a shadow of 81 feet? Draw a diagram and solve for the height of the tree.
May 21, 2014

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.
November 4, 2013

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...
November 3, 2013

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....
November 3, 2013

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 ...
November 3, 2013

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 :)
November 2, 2013

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
November 2, 2013

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 ...
November 2, 2013

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? *
April 17, 2013

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? *
April 17, 2013

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? *
April 17, 2013

Physics
,,,,,,
February 13, 2013

Math
Thank you Ms. Sue - Happy Holidays to you!
December 21, 2012

Math
(ACB)24
December 21, 2012

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 _____?
December 21, 2012

Algebra
You're awesome, thank you much and Happy Holidays to you!
December 21, 2012

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
December 21, 2012

Algebra
You're awesome, thank you much and Happy Holidays to you!
December 21, 2012

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.)
December 21, 2012

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?
December 21, 2012

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...
December 21, 2012

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
June 28, 2012

living life a health life
what are the three methods by which HIV and AIDS are usually transmitted?
June 27, 2012

Math
5w=42
January 29, 2012

college
Evaluate the difference quotient for the given function. Simplify your answer. f(x) = 3 + 5x − x2, f(4 + h) − f(4) h
September 11, 2011

LIfe orientation
5 ways : Water and sanition , Population
April 26, 2011

math
(9x^4+0x^3+8x^2+17x-20)÷(-3x-4)
February 24, 2011

Physics
sdf
November 25, 2010

math
The sum of the page numbers on the facing pages of a book is 457. Find the page numbers?
November 15, 2010

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 ...
May 4, 2010

chem
method of producing aspirin
March 13, 2008

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 ...
January 20, 2008

Pages: 1

Search
Members