DC
Most popular questions and responses by DC
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,
asked on November 3, 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
asked on November 2, 2013 
Math
azmin decided to get some exercise by taking the stairs from the first to the fifth floor in her apartment building. The first time she went up the entire flight, she walked up some steps and ran up 16 steps. This took a total of 60 seconds. The second
asked on October 29, 2015 
math
In a grand prix automobile race, Speedy Ryder averaged 110 miles per hour for the first half of the course and 130 miles per hour for the second half of the course. Cannonball Carter maintained a constant speed of 120 miles per hour throughout the race.
asked on December 3, 2015 
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
asked on December 21, 2012 
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
asked on November 3, 2013 
physics
A 34kg 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.
asked on November 4, 2013 
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
asked on December 21, 2012 
math
carmen is a girl scout camp counselor and needs to assign scouts to tents. She noticed that if two scouts were assigned to each tent then six girls would have no tent. On the other hand, if four scouts were assigned to each tent then there will be three
asked on December 3, 2015 
math
The entire second grade at Sunshine Elementary participated in a single elimination checkers tournament. There are a total of 118 second graders and so there were 59 matches in the first round of the tournament. In the second round,the 59 remaining
asked on October 30, 2015 
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
asked on May 4, 2010 
math
Tasha’s school bus usually drops her off in town every day at 4pm and her mother picks her up at the bus stop. Last Friday was a short school day, only Tasha’s mother forgot so she wasn’t at the bus stop when Tasha was dropped off an hour early, at
asked on November 10, 2015 
Math
Multiply. write each product in simplest form. 3 7/10 X 7
asked on October 9, 2016 
math common core
1/4 pages typed per minute how many pages can be typed in 18minutes
asked on September 27, 2016 
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.
asked on May 21, 2014 
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? *
asked on 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? *
asked on April 17, 2013 
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
asked on December 21, 2012 
college
Evaluate the difference quotient for the given function. Simplify your answer. f(x) = 3 + 5x − x2, f(4 + h) − f(4) h
asked on September 11, 2011 
math
two cars are approaching each other on the same highway one from san bernardino at 80 mph and the other from las vegas at 60 mph how far apart are they on the highway one hour before they meet?
asked on November 10, 2015 
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.)
asked on December 21, 2012 
math
(9x^4+0x^3+8x^2+17x20)÷(3x4)
asked on February 24, 2011 
Maths
The projection of a line on axes are 6,2,3. What will the direction cosines of the lines be?
asked on October 21, 2016 
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
asked on June 28, 2012 
living life a health life
what are the three methods by which HIV and AIDS are usually transmitted?
asked on June 27, 2012 
math
The sum of the page numbers on the facing pages of a book is 457. Find the page numbers?
asked on November 15, 2010 
chem
method of producing aspirin
asked on 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 rightthinking people will
asked on January 20, 2008

Math
idk
posted on September 3, 2018 
Maths
Here, P=Q1 Now, PQ = Q1  Q = 1 Therefore, PQ=1
posted on October 21, 2016 
Maths
10
posted on October 21, 2016 
Math
x>55
posted on September 5, 2016 
Biology
ribosome structure
posted on May 27, 2016 
physics
71
posted on November 19, 2015 
Physics
,,,,,,
posted on March 26, 2014 
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) =
posted on November 4, 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 :)
posted on 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
posted on 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? *
posted on April 17, 2013 
Math
Thank you Ms. Sue  Happy Holidays to you!
posted on December 21, 2012 
Math
(ACB)24
posted on December 21, 2012 
Algebra
You're awesome, thank you much and Happy Holidays to you!
posted on December 21, 2012 
Algebra
You're awesome, thank you much and Happy Holidays to you!
posted on 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?
posted on December 21, 2012 
Math
5w=42
posted on April 16, 2012 
LIfe orientation
5 ways : Water and sanition , Population
posted on May 9, 2011