Thursday
December 18, 2014

Posts by Dan


Total # Posts: 910

Chem
So I corrected my errors but am still confused. Should I convert torr to ATM or KPa to get R?
December 18, 2014

Chemistry
Ok thanks for your help!
December 17, 2014

Chemistry
Oxygen gas can be generated by heating KClO3 in the presence of a catalyst. KClO3 KCl + O2 (unbalanced) What volume of O2 gas will be generated at T = 35°C and P = 764.0 torr from 1.51 g of KClO3? I got .414 L and used 22.4 L for moles of O2 What's going on??
December 17, 2014

Stats
Consumption of alcoholic beverages by young women of drinking age has been increasing in the United Kingdom, the United States, and Europe (The Wall Street Journal, February 15, 2006). Data (annual consumption in liters) consistent with the findings reported in The Wall Street...
December 16, 2014

Calculus
Find the derivative of 1/(1+(x-3)^2) Steps would be appreciated.
December 15, 2014

Physics
In an electricity experiment, a 0.900g plastic ball is suspended on a 50.0cm long string and given an electric charge. A charged rod brought near the ball exerts a horizontal electrical force F⃗ elec on it, causing the ball to swing out to a 23.0∘ angle and remain ...
December 15, 2014

Trig
Jane has a bike with a 22-inch rear wheel. The wheel sprocket is 3 inches in diameter and the pedal sprocket is 4 inches in diameter (the sprockets hold the chain.) How fast in miles per hour is she going if she pedals at a rate of 100 revolutions per minute?
November 17, 2014

science
thanks
November 17, 2014

science
if you get cut a type of metal in two pieces do they both have the same density
November 17, 2014

Geometry
What is the formula for finding the central angle of a sector when given the radius and arc length?
November 11, 2014

physics
A 1.2 lead ball is launched off a cliff top at 16 m/s Determine the balls kinetic energy at position P. Ignore friction
November 6, 2014

chemistry
I am not understanding what you are saying? So what would be the answer? Li is a solid and Fe(NO3)3 is aqueous
November 3, 2014

chemistry
Not sure how to complete this chemical reaction: Li + Fe(NO3)3 --->
November 3, 2014

Chi-Test explaination
Can someone explain how to conduct a Chi-test in depth?
October 13, 2014

Math
Question If there is a Part B. Like Using the following information: B(s)--B(aq) Delta H=+23.8 KJ/mole 2B(aq)---A (aq) Delta H= -1.25 KJ/mole Calculate ÄH°rxn for the following reaction (in kJ/mol). A(s)---2B(s) How exactly would you do that?
October 5, 2014

physics
Three forces act on a moving object. One force has a magnitude of 62.6 N and is directed due north. Another has a magnitude of 45.9 N and is directed due west. What must be (a) the magnitude and (b) the direction of the third force, such that the object continues to move with ...
October 3, 2014

Math
Mr Kim mix cement and sand to make a mixture.He uses 2 pails of cement for every 5 pails of sand. (A) Find the ratio of the number of pails of cement to the number of pails of sand. (B) If he uses 24 pails of cement,how many pails of sand does he use? (C) If he uses 35 pails ...
October 2, 2014

Physics-Intro
Find the total force necessary to give a rocket of mass 25,000 slugs an acceleration of 28.0 ft/s2.
September 30, 2014

computers
Is there a way to find out some information about an e-mail address without actually sending a message? As in, is it still in active use? Or, who is the person using it?
September 29, 2014

physics
A sprinter starts from rest and accelerates for 5s. He then travels at a constant velocity for 10s. Finally he slows down to a stop in 5s. Draw a distance time graph to represent his motion.
September 17, 2014

Physics please help
So i just find the slope of the curve
September 16, 2014

Physics please help
How do I convert a distance time graph into a velocity time graph. I am given a distance time graph with three curves but i am not sure how to calcualte the area of them to get the velocity time graph.
September 16, 2014

Physics
Heather and Jerry are standing on a bridge 43m above a river. Heather throws a rock straight down with a speed of 12m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance.
September 11, 2014

English
In wuthering heights, what are the most influential forces in the shaping of a childs values and behaviour? Parents, guardians, or other family members?schooling? Friends? I think the answer would be parents, guardians or other family members
September 9, 2014

Biology please help!
Is respiratory control more sensitive to small changes in arterial PO2 or in arterial PCO2
September 8, 2014

English
What role, according to Dessner, does irony play in the story A&P by John Updikes? What levels of irony are at work in the story? For example, what does he identify as " charming irony" as compare to " deeper irony"? Explain
August 30, 2014

Chemistry
Using Hess’s Law with the following data: N2(g) + O2(g) = 2NO(g) Del(H) = 180.7kj 2NO(g) + O2(g) = 2NO2(g) Del(H)= -113.1kj 2N2O(g) = 2N2(g)+ O2(g) Del(H)=-163.2kj Calculate Del(H) for the reaction: N2O(g) + NO2(g) = 3NO(g)
July 29, 2014

Chemistry
Calculate the value of the standard enthalpy change for each of the following reactions (standard enthalpy for Na2SO4(s) is -1375.653 kj/mole): a)4HBr(g) + O2(g) = 2H2O(I) + 2Br(I) b)2Na(OH)(s) + SO3(g) = Na2SO4(s) + H2O(g) c)CH4(g) + 4CI2(g) = CCI4(I) + 4HCI(g) d)Fe2O3(s) + ...
July 3, 2014

Chemistry
Using standard enthalpies information, calculate the standard enthalpy change for this reaction. a)(thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b)Mg(OH)2(s) = MgO(s) + H2O(I) c)N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d)SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)
July 3, 2014

Chemistry
Given the Data: N2(g) + O2g) = 2NO(g) delta H = 180.7kj, 2NO(g) + O2(g) = 2NO2(g) delta H = 0113.1kj, 2N2O(g) = 1N2(g) + O2(g) delta H = -163.2kj. Using Hess’s Law calculate delta H for the reaction: N2O(g) + NO2(g) = 3NO(g)
July 3, 2014

Chemistry
A solution of hydrogen peroxide, H2O2, is titrated with potassium permanganate, KMnO4, according to the following equation: 5H2O2 + 2KMnO4 + 3H2SO4 = 5O2 + 2MnSO4 + 8H2O + K2SO4. It requires 46.0 mL of 0.145 Mol/L KMnO4 to titrate 50.0 mL of the solution of H2O2. What is the ...
July 3, 2014

music
I think your ideas are great,but you need to decide together. Why don't you talk to them and negotiate the correct song to fit with you. Find a time at school, after school, at a dance studio or all of them. It is great to practice and practice does make perfection. If ...
June 7, 2014

Math
Please help, I don't understand.
May 23, 2014

Math
What is the degree of the monomial? 6x^5
May 23, 2014

Physics
1.How are alternating and direct current different? 2.Who invented direct current? 3.Who invented alternating current? 4.What are some of the advantages of alternating current? 5.Do all devices that plug into the wall run on alternating current? Why/why not? 6.What is the ...
May 20, 2014

chemistry
20 mL of 0.125 M potassium iodide solution is mixed with 10 mL of 0.1 g L–1 sodium thiosulfate solution and 0.2 g of solid iodine indicator is added. To this solution is added 20 mL of 0.025 M peroxodisulfate solution. After 46 seconds a blue colour appears, indicating ...
May 9, 2014

PHYSICS HELP
A long, ideal solenoid has a diameter d=12cm and n=1200turns/meter carrying current I=20A. If the current is lowered at 4.33amp/s to zero, what is the magnitude of the induced electric field in V/m at a position 8.2cm from the solenoid's axis
April 8, 2014

Physics
If an object has a work of 300J and a displacement of 20m, how would I determine the net force?
April 4, 2014

chemistry
Plan how you would make 100mL of a buffer solution with a pH of 10.80 to be made using only sodium carbonate, sodium hydrogen carbonate and water. You should specify the amount of sodium carbonate and sodium hydrogen carbonate that you would use. Below is what i got up to then...
April 4, 2014

chemistry/science
Not sure if i posted this but Need help with my pH calculations? 0.10 mol of solid sodium hydrogen carbonate and 0.20 mol of solid sodium carbonate are dissolved in the same beaker of water, transferred to a volumetric flask and made to 250.0 mL. The Ka for HCO3 – ...
April 4, 2014

chemistry
Need help with my pH calculations? 1) 0.10 mol of solid sodium hydrogen carbonate and 0.20 mol of solid sodium carbonate are dissolved in the same beaker of water, transferred to a volumetric flask and made to 250.0 mL. The Ka for HCO3 – is 4.7 x 10–11. a) ...
April 4, 2014

Physics
A satellite is given a boost of 540 MJ of energy to move it from its initial orbit at an altitude of 150 km to a higher altitude orbit. If the satellite has a mass of 1.16 ✕ 10^3 kg, what is the new altitude it reaches? Take the mass of the Earth to be 5.97 x 10^24 kg ...
April 2, 2014

Physics-Gravitational Potential Energy
A satellite is given a boost of 540 MJ of energy to move it from its initial orbit at an altitude of 150 km to a higher altitude orbit. If the satellite has a mass of 1.16 ✕ 103 kg, what is the new altitude it reaches? Take the mass of the Earth to be 5.97 x 10^24 kg ...
April 1, 2014

Physics
A snowmobile, with a mass of 530 kg, applied a force of 410 N backwards on the snow. a) What force is responsible for the snowmobile’s resulting forward motion? (Hint: Think action–reaction force pairs.) b) If the force of friction on the snowmobile is 187 N ...
March 28, 2014

Physics( Explain and choose right answer)
A ball on the end of a rope is moving in a vertical circle near the surface of the earth. Point A F T is at the top of the circle; C is at the bottom. Points B and D are exactly halfway between A and C. Which one of the following statements concerning the tension in the rope ...
March 24, 2014

Physics( Explain and choose right answer)
A 3 kg cat sitting on a 1.5 kg piece of cardboard on a frozen lake wants to jump to shore without touching the ice. If there is no friction between the cardboard and the ice, when the cat jumps. the cardboard will move in the opposite direction with a velocity: A. half as ...
March 24, 2014

Chem
The density of ethanoic anhydride is 1.092 g/mL. Use this value, and the amount that you used in the laboratory to show that ethanoic anhydride is in excess for your preparation of ASA?, 2.5ml of ethanoic anhydride was used.
March 14, 2014

English
A?
March 6, 2014

English
Which implicit element of the analogy in these lines is analogous to "family worship"? Breakfast over, Aunt Polly had family worship: it began with a prayer built from the ground up of solid courses of Scriptural quotations, welded together with a thin mortar of ...
March 6, 2014

Please help with Chemistry?????
5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the mixed ...
February 26, 2014

Please help with Chemistry?????
A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
February 26, 2014

Chemistry
A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
February 26, 2014

Chemistry
5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the moxed ...
February 26, 2014

Math
Interest is a concept familiar to most people: every credit card in existence has a term called annual percentage rate (APR), which is an interest rate. Suppose you charged $1,000 to a credit card that has a minimum payment each month equal to the interest owed. Can you figure...
February 18, 2014

Math
The formula for simple interest is where I is the amount you will pay in interest, r is the rate at which interest will accrue, P is the principal (amount borrowed), and m is the number of times the interest is applied. To solve for the interest rate of your credit card, you ...
February 18, 2014

Math
B?
February 18, 2014

Math
Gabe is the human resource manager for the Advanced Scientific Research Lab. He has to record the heights (in centimeters) and weights (in pounds) for each of the scientists in the lab. Height distribution (cm): 178, 163, 174, 186, 154, 167, 167, 181, 159, 165, 177, 191, 158 ...
February 18, 2014

AP chem
Mostly just setting up my reaction to use for each problem
February 5, 2014

AP chem
Consider the titration of 50.00 ml .250 M HBr with .100 M Ba(OH)2. What is the pH after the following additions of Ba(OH)2 to the 50 ml of hydrobromic acid? 0 ml. 15 ml. 25 ml. 50ml. 51ml.
February 5, 2014

programming
using pseudocode debug the following 3 programs // A high school is holding a recycling competition // This program allows a user to enter a student's // year in school (1 through 4) // and number of cans collected // Data is entered continuously until the user wants to ...
January 13, 2014

Physics
I got it!!! Thank you!!!
December 24, 2013

Physics
I dont understand it, can you please explain it to me?.. Thanks
December 24, 2013

Physics
I think it is. and it's not one person, we study in a group. Thank You.
December 24, 2013

Physics
A pilot, whose mass is 91.0 kg, makes a loop-the-loop in a fast jet. Assume that the jet maintains a constant speed of 125 m/s and that the radius of the loop-the-loop is 0.478 km. What is the apparent weight that the pilot feels (i.e., the force with which the pilot presses ...
December 24, 2013

Physics
Thank you so much Elena!!
December 24, 2013

Pre-Calc
Using the difference for formula, find the tan 255. Step by step would be appreciated
December 18, 2013

Math Quiz
Math Quiz please help fast Write the following ratio in simplest form: 32 min:36 min (1 point) 8:9 8:36 32:9 128:144 2. Marie saved $51. On Wednesday, she spent $8 of her savings. What ratio represents the portion of her total savings that she still has left? (1 point) 43:8 8:...
December 12, 2013

Maths
Will it be 16x^2-40x+25
November 18, 2013

Maths
(4x-5)^2
November 18, 2013

Maths
(5x+4)(5x-4)=
November 18, 2013

physics
You apply a potential difference of 5.00 V between the ends of a wire that is 2.65 m in length and 0.654 mm in radius. The resulting current through the wire is 17.6 A. What is the resistivity of the wire?
October 20, 2013

Math
Carla and Candice left from the same place at the same time and rode their bikes in the same direction along a straight road . Candice biked at an average speed that was three-quarters of Carla's average speed. After 2 hours they were 28 miles apart. What was the average ...
October 7, 2013

Math
The area of each trapezoid is 3 times the area of one triangle. The area of one triangle is six square units. What is the total area of the figure in square units?
September 23, 2013

Algebra word prob
If you graph the table of values and draw a line through the coordinates, the graph will look like a parabola. Thus the equation is quadratic. Since you don't have a graphing calculator, I will give you the resulting a/b/c values that it comes up with, but the rest is for ...
September 10, 2013

Math
2. True or false. Suppose the slope of a straight line L is -3/4 and P is a given point on L. If Q is a point on L lying 2 units to the right of P, then Q is situated 3/2 units below P. Prove why.
August 27, 2013

physics
The Hyperloop is a hypothetical new fast transport system between cities, which works by launching pods that carry people through a very low air pressure tunnel. The Hyperloop reduces friction between the pods and the tunnel by supporting the pod on a cushion of air. This air ...
August 22, 2013

Statistics
Hola ¿Cuál es el P - value en este problema que escribiste?
July 29, 2013

Math
A circle of radius 1 is drawn in the plane. Four non-overlapping circles each of radius 1, are drawn (externally) tangential to the original circle. An angle γ is chosen uniformly at random in the interval [0,2π). The probability that a half ray drawn from the centre...
June 24, 2013

Math
There are 100 runners, each given a distinct bib labeled 1 to 100. What is the most number of runners that we could arrange in a circle, such that the product of the numbers on the bibs of any 2 neighboring runners, is less than 1000?
June 23, 2013

Math
γ is a permutation on eight elements, though you are not told which permutation it is. If γ is applied to an 8-element set, what is the minimum number of additional times we must apply γ to the resulting set in order to guarantee the set is back in its original ...
June 18, 2013

Physics 1
A body of mass 6kg moving at 8m/s collides with a stationary body of mass 10kg and sticks to it. Find the speed of the composite body immediately after the impact.
June 10, 2013

Math (Algebra)
Thanks Steve!
May 21, 2013

Math (Algebra)
f(x) is a cubic polynomial that satisfies f(1)=f(2)=f(3)=4 and f(0)=0. What is the value of f(7)?
May 21, 2013

Math (Probability)
Please tell the answer. I'm not able to get it. Thanks.
May 21, 2013

Math (Probability)
Bret and Shawn are playing a game where each turn the players roll a 20-sided die fair and then add the number they get to their score. The winner is the player with the highest score at the end of the game (there may be a tie). Before the last turn, Shawn is winning by 10 ...
May 21, 2013

Math (Algebra)
A number is called algebraic if there is a polynomial with rational coefficients for which the number is a root. For example,√2 is algebraic because it is a root of the polynomial x^2−2. The number √2+√3+√5 is also algebraic because it is a root ...
May 21, 2013

Physics
A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
May 21, 2013

Math (Combinatorics)
Six boxes labeled 1,2,…,6 are arranged in a line. Seven identical balls are to be placed into the boxes such that for any 1 ≤ k ≤ 6, there are at least k total balls amongst boxes 1,2,…k. How many different placements of the balls into the boxes are ...
May 21, 2013

math
or 9√970/500.
May 20, 2013

math
It's 0.5606068140863.
May 20, 2013

Physics
A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
May 20, 2013

Geometry
Perimeter of Rectangle = 2L + 2W where: L = length, and W = width Perimeter = 2(8) + 2 (6)= 28 inches Area of Rectangle = L x W Area = (6in)(8in) = 48 inches squared.
May 20, 2013

heeelp MATH
Yes please Reiny. It would help me a lot. Thanks! :)
May 16, 2013

Math (Geometry)
ABC is a triangle with a right angle at A. M and N are points on BC such that AM is the altitude, and AN is the angle bisector of ∠BAC. If CN/NB=21, what is CM/MB?
May 16, 2013

Math (Geometry)
ABC is a triangle with a right angle at A. M and N are points on BC such that AM is the altitude, and AN is the angle bisector of ∠BAC. If CN/NB=21, what is CM/MB?
May 15, 2013

Math (Geometry)
Thanks hans!
May 15, 2013

Math (Geometry)
A point P is given outside of a circle Γ. A tangent from P to Γ touches Γ at T with PT=45. A line from P cuts Γ at the 2 points A,B. If PA=25, what is the length of PB?
May 15, 2013

Math (Geometry)
ABCD is a parallelogram with side lengths AB=15,BC=10 and ∠ADC=75∘. A point P in the interior of the parallelogram is chosen such that ∠APD+∠CPB=180∘. What is the measure (in degrees) of ∠PAD+∠PCB?
May 15, 2013

Math (Probability)
When Lino submitted an essay for his English class, it was 9 pages long. Lino's essay had errors on pages 2 and 7. If the teacher chose 3 pages uniformly at random to read, then the probability that she didn't read any of the pages with errors can be expressed as a/b ...
May 15, 2013

Math - Maximizing Logarithm
x and y are positive values satisfying x + y = 1/4. When ln(y^2+4xy+7) attains its maximum (subject to the given constraint), what is the value of 1/xy?
May 13, 2013

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