Saturday
February 6, 2016

# Posts by john

Total # Posts: 7,279

chemistry
3. Calculate the standard entropy change for the reaction: N2 + 3H2 → 2NH3 given the standard entropies Sº(N2)(g) = 191.6 J K^-1 mol^-1 Sº(H2)(g) = 130.6 J K^-1 mol^-1 Sº(NH3)(g) = 193.3 J K^-1 mol^-1
July 19, 2014

chemistry
2. Calculate the enthalpy change of combustion for ethene gas (C2H4) given the following enthalpy changes of formation: ΔHºf(C2H4)(g) = +52 kJ mol^-1 ΔHºf(CO2)(g) = -394 kJ mol^-1 ΔHºf(H2O)(g) = -286 kJ mol^-1
July 19, 2014

chemistry
1. Calculate the standard enthalpy change for the reaction: C2H4(g) + H2(g) → C2H6(g) given that the enthalpy of combustion for the reactants and products are: ΔHºc(C2H4)(g) = -1411 kJ mol^-1 ΔHºc(C2H6)(g) = -1560 kJ mol^-1 ΔHºc(H2)(g) = -...
July 19, 2014

math
Carrie can inspect a case of watches in 5 hours. James can inspect the same case of watches in 3 hours. After working alone for 1 hour, Carries stops for lunch. After taking a 40 minute lunch break, Carrie and James work together to inspect the remaining watches. How long do ...
July 17, 2014

math
mr. lee had a bag of red beans and a bag of black beans. 20% of the total number of beans were black, and there were 180 ounces more red beans than black beans. he transferred some red beans to the bag containing black beans, so that, the bag now contained 30% of the total ...
July 17, 2014

math
A Number N Divides Each Of 17 And 30 With The Same Remainder In Each Case. What Is The Largest Value N Can Have?
July 17, 2014

math
All sides are congruent.
July 16, 2014

nau
4x+y=21 7x-4y=8 21*8=168 ------------- 8(4x+y)=21(7x-4y) Solve
July 16, 2014

math
A girl walks 3/4 of the way home in 18 minutes. At the same rate, she can walk the rest of the way home in A. 4 1/2 minutes B. 6 minutes C. 9 minutes D. 24 minutes
July 16, 2014

math
A girl walks 3/4 of the way home in 18 minutes. At the same rate, she can walk the rest of the way home?
July 16, 2014

math
In a certain class there are 12 boys and 18 girls. If the class average for an algebra exam is 90 and the boys' average score is 87, what is the girls' average score?
July 16, 2014

accounting
A partner withdrew Rs.2000 at the beginning of every month.the rate of interest on drawings is 10%per annum. What is the amt. of interest?
July 14, 2014

Soil Chemistry
how is carbon dioxide different than water in terms of the behavior of each compound in Earth's atmosphere?
July 11, 2014

Clincal
A 12-year-old boy presents with his farther to the ER due to open wounds to his arm, hand, and upper leg. The injury occurred when the boy fell on a barbed-wire fence at the farm while running in the field. Diagnosis: Multiple lacerations to the right forearm, right hand, and ...
July 11, 2014

Commerce
Would it be called statistic, if it is said that there are 2000 students in the school
July 10, 2014

Physics
An automobile moving at a constant velocity of 25m/s passes a gasoline station. Two seconds later, another automobile leaves the gasoline station and accelerates at a constant rate of 4.0m/s^2. how soon will the second automobile overtake the first?
July 10, 2014

physics
what is the resultant of two 65N identical one acting easterly and the northerly
July 8, 2014

english
What is Bronte's main purpose in describing Jane's meals and activities at Lowood? A)to show how all schools operate B) to show the discomforts she endures at Lowood C) to show the interesting aspects of Jane's life at Lowood D) to show how students interact with ...
July 7, 2014

chemistry
How many mol of Argon is required to exert a pressure of 1.00 MPa at 50 ºC in a vessel that has a volume of 14 litres? (R = 8.314 J K^-1 mol^-1)
July 6, 2014

chemistry
What is the volume of 14 mol of ideal gas if its pressure is 233 kPa and its temperature is 140 ºC? (1 mol of ideal gas at STP occupies 22.4 L).
July 6, 2014

chemistry
2.00 m^3 of nitrogen gas at 14 ºC and 100 kPa is compressed to occupy 0.50 m^3. and its temperature rises to 42 ºC. Calculate the new pressure of the gas
July 6, 2014

chemistry
calculate the mass of water contained in 4.021 m^3 of saturated air at 27 ºCgiven that the saturate d vapour pressure of water at 27 ºC is 3.53 kPa. (RMM of water is 18.02, R = 8.314 J K-1 mol^-1
July 6, 2014

Soil Chemistry
Understanding the strengths of carbon halogen bonds can help us to understand the behavior of CFCs and related molecules. Arrange the members of the set of carbon halogen bonds shown below in the order of bond strength. A) carbon dioxide B) methane C) ozone D) water A) c > ...
July 6, 2014

math
there are seven consecutive even numbers .if the largest no is x write an algebraic expression for the middle no . if the middle no is 48 find the value of smallest no
July 6, 2014

Soil Chemistry
Understanding the strengths of carbon halogen bonds can help us to understand the behavior of CFCs and related molecules. Arrange the members of the set of carbon halogen bonds shown below in the order of bond strength. A) carbon dioxide B) methane C) ozone D)water A) c > b...
July 5, 2014

Soil Chemistry
Gasoline producers add oxygenated chemical compounds to reduce the amount of carbon monoxide produced when the fuel is burned. Methyl t-butyl ether (MTBE) is one such oxygenate that is no longer used because of health and environmental concerns. what are the correct exponents ...
July 5, 2014

Soil Chemistry
thank you so much damnon....and thanks for the article...I have a way better understanding of it now...:)
July 5, 2014

Soil Chemistry
Global temperatures are increasing and this increase is probably due to increasing concentrations of greenhouse gases present in A) the troposphere which absorbs outgoing IR radiation B) the stratosphere which absorbs outgoing IR radiation C) the troposphere which absorbs ...
July 5, 2014

AP Macroeconomics
Assume that the mix of goods in a basket is kept constant for long periods. If the price of one good rises very rapidly over several years, what will happen to the relative importance of the other goods in the basket? Is this a problem? If the price of coffee increases, we get...
July 3, 2014

english
What is Bronte's main purpose in describing Jane's meals and activities at Lowood?
July 2, 2014

Soil Chemistry
I am only given P1V1T1 though...I am not given the other values..P2V2 and T2
July 1, 2014

Soil Chemistry
Using the gas laws, calculate the new volume of methane gas at STP, which has escaped from a landfill and been captured at an initial pressure of 1.50atm, an initial volume of 30.0L and an initial temperature of 40.0C.
July 1, 2014

Soil Chemistry
an initial pressure of 1.50atm, an initial volume of 30.0L and an initial temperature of 40.0C.
July 1, 2014

Soil Chemistry
Chlorine is widely used to treat municipal water supplies and swimming pools. If the volume of a sample of Cl2 gas is 8.73L at 755mmHg and 24.0C, how many grams of Cl2 gas are in this sample? This is one of those multi step problems that I get lost....I need to to know how to ...
June 30, 2014

Soil Chemistry
In saturated soils, oxygen is quickly depleted and microbes must utilize the next most favorable electron acceptor, in this case sulfate (SO42-). Under these conditions, Mn (and Fe) are oxidized to Mn2+ (and Fe2+). Select the correct oxidation and reduction pair for Mn. A. ...
June 30, 2014

economic
Management and ownership of business are separate A) Sole Proprietorship B) Corporation C) Partnership I said a
June 30, 2014

math
100-41= 59
June 30, 2014

Math
Integrate and simplify the following function: y= ∫(ln√x/x^2)+x 2^(3-5x^2))dx
June 29, 2014

Math
Show that the derivative of y= cosh-1 (2x-1) is: dy/dx = √1/(x2-x)
June 29, 2014

physics
A missile is fired from a launcher with an initial velocity of 250 m/s at a target located 500 m above the launcher and at a horizontal distance of 3000 m. Determine the following: i) The possible firing angles required to hit the target. ii) The maximum height reached for all...
June 29, 2014

chemistry
Draw “arrows in a box” diagrams to illustrate the ground-state electronic configuration of the following species: 12 6C , 32 2 16 S − 28 14 Si , 57 2 28 Ni + , 35.5 17Cl− , 40 2 20Ca + , 31 15P
June 22, 2014

chemistry
Sulphuric acid (H2SO4) solution reacts with magnesium metal (Mg) to magnesium sulphate and hydrogen according to: H2SO4 + Mg → MgSO4 + H2 How many litres of 5.00 M sulphuric acid would be required to dissolve 20.00 g of magnesium and how many mol of hydrogen would be ...
June 22, 2014

ALGERBRA
A STATE LOTTERY IS DESIGNED SO THAT A PLAYER CHOOSES FIVE NUMBERS FROM 1 TO 30 ON ONE LOTTERY TICKET. WHAT IS THE PROBABILITY THAT A PLAYER WITH ONE TICKET WILL WIN? WHAT IS THE PROBABILITY OF WINNING IF 100 DIFFERENT TICKETS ARE PURCHASED?
June 18, 2014

Statistics
The complement of P(B | A) is 1 - P(B | A). Is it also true that 1 - P(B | A) = P(B' | A), where B' means the complement of B?
June 13, 2014

Math
In a sample of 78 widgets, 2 were defective. How many defective widgets would you expect in a sample of 468 widgets?
June 12, 2014

Physics (electricity and Magnetism)
A long straight and thin wire has a charge Q per unit length. It is also carrying a current I. A point charge is moving with a velocity v parallel to the conductor, at a distance d from it. Find the velocity v, supposing a correct direction for the current and the current ...
June 1, 2014

math
gail borrowed \$3600 from a bank to buy a washing machine she pays back the loan in 24 monthly instalments at a simple interest rate of 2% a)calculate the simple interest on the loan b)the total amount to be repaid c)if gail repays the loan in 24 equal instalments ,find the sum...
May 31, 2014

Physics
A projectile is launched at an angle of 34.0o above the horizontal. The projectile has a mass of 1.50 kg and is given an initial speed of 20.0 m/s. a) What is the initial kinetic energy of the projectile? b) By how much does the gravitational potential energy of the projectile...
May 30, 2014

Geometry
If m<AHM = 3x+5 and m<TMH = 7x-27, find m<AHM prntscr(dot)com/3n61w3 For figure required for problem.
May 27, 2014

chemistry
How much naoh and hno3 is needed to make nano3?
May 26, 2014

maths
If x and y are positive integers, and square root = y + 3, then y^2 = ?
May 26, 2014

physics
Gamma rays (ã-rays) are high-energy photons. In a certain nuclear reaction, a ã-ray of energy 0.510 MeV (million electronvolts) is produced. Compute the frequency of such a photon.
May 24, 2014

appliance repair
Which one of the following letters is used in formulas as the symbol for voltage? A. P B. W C. I D. E
May 22, 2014

Help me? Thanks~
22. The joints highlighted in the image below are ______________ joints. image of transparent body with the spine highlighted the answer is vertbrate
May 22, 2014

Making a vaccine for HIV is difficult because the virus has a rapid rate of (A)__________. This is because it is a(n) (B)________ - its genetic material is RNA instead of DNA.
May 21, 2014

English
The question was "What lesson or meaning do you think this story held for the British audience of the Victorian Era?" This is for the story The Mark of the Beast by Rudyard Kipling. I was thinking that the answer was that the lesson was that just because someone ...
May 21, 2014

Calculus
An inverted conical tank is 3m tall and 1m in diameter at its widest point. The water is being pumped out of a spout 2m above the top of the tank. Recall that the density of water is ρ = 1000kg/m^3 (a) Find the work needed to empty the tank if it is full. Include units. (...
May 20, 2014

biology
budding
May 19, 2014

Chemistry
could you set this up for the first one for me please then i can do the other two
May 18, 2014

Chemistry
Calculate ΔG∘ at 298 K for the following reactions. Ca(s)+CO2(g)+12O2(g)→CaCO3(s) 2KClO3(s)→2KCl(s)+3O2(g) CO(g)+H2O(g)→H2(g)+CO2(g)
May 18, 2014

Need help with pre cal hw
1. A party of hikers walks 8 km from camp on 30 degrees, then turns and walks 6 km on course 160 degrees. Find the magnitude of the net displacement from camp. 2. A ship leaves port A and sails 61.1 km course 131 degrees 50' to point B. Then it sails 76.5 km on course 36 ...
May 18, 2014

Algebra
Update ?
May 16, 2014

Math 2
1/5 / 10 = 1/5 * 1/10 = 1/50 So d
May 14, 2014

Algebra
So we get -10 < -2 +8x and -2+8x<22 now we have -8<8x and 8x<24 so we have -1<x and x<3 thus -1<x<3
May 14, 2014

Algebra
break into two equations
May 14, 2014

Chemistry
Tarnish on iron is the compound FeO. A tarnished iron plate is placed in an aluminum pan of boiling water. When enough salt is added so that the solution conducts electricity, the tarnish disappears. Imagine that the two halves of this redox reaction were separated and ...
May 14, 2014

ALGEBRA
there is an error in the equatiion i believe?
May 14, 2014

Chemistry
Ni2+(aq)+Mg(s)→Ni(s)+Mg2+(aq) Indicate the half-reaction occurring at Anode. Indicate the half-reaction occurring at Cathode.
May 14, 2014

History
Are you talking bout Canadian History?
May 13, 2014

Geometry
Let O and H be the circumcenter and orthocenter of triangle ABC, respectively. Let a, b, and c denote the side lengths, and let R denote the circumradius. Find OH^2 if R = 7 and a^2 + b^2 + c^2 = 29. I tried to draw a diagram but it didn't work out too well. Could I have ...
May 13, 2014

Math Solve for X?
You should multiply both sides by x^2+5x-24 so we get 5x^2-12x <= 0 now we get 5x^2 <= 12x Divide both sides by x and we get 5x <=12 so x <= 12/5
May 13, 2014

math
Plug in some numbers.
May 13, 2014

geometry
correct so it is equal to 500 * (1+0.04)^5 Now solve
May 13, 2014

Programming Concepts
Try stackoverflow. com
May 13, 2014

Physics
A 0.28 kg softball has a velocity of 16 m/s at an angle of 34° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of (a) 21...
May 13, 2014

math
A room is18 ft long 14 ft wide and 8 ft high. Find the cost of carpeting the floor with carpet \$5\ft2
May 8, 2014

statistics
a) 12 b) 12 c) 0
May 8, 2014

Chemistry
Butane, C4H10, is a component of natural gas that is used as fuel for cigarette lighters. The balanced equation of the complete combustion of butane is 2C4H10(g)+13O2(g)→8CO2(g)+10H2O(l) At 1.00 atm and 23 ∘C, what is the volume of carbon dioxide formed by the ...
May 6, 2014

algebra
Please Explain how to factor the following trinomials forms: x2 + bx + c and ax2 + bx + c in words.
May 6, 2014

algebra
Factor the expression. x2 + 2x + 24 HintX
May 5, 2014

First off the 2 people who answered are complete morons, and i'm having the same issue. but i'd probably have to say it's either B or C
May 5, 2014

physics
A metal ball of mass 1.8 kg with initial temperature of 46.5 C is dropped into a container of 3 kg of water at 15 C. If the final temperature is 22.6 C, what is the specific heat of the metal? metal = ____ J/kg*C?
May 4, 2014

Chemistry
Aniline, C6H5NH2, is a weak base. If the hydroxide ion concentration of a 0.223 M solution is 9.7 10-6 M, what is the ionization constant for the base?
May 1, 2014

Statistics
From the following list of number of discharges each day in September, compute the mean, median, mode, and range. Round the mean and median to one decimal point. Day # of discharges 1 27 2 22 3 35 4 63 5 42 6 55 7 62 8 65 9 32 10 35 11 36 12 75 13 65 14 84 15 37 16 38 17 62 18...
April 24, 2014

physics
A 225-kg box is pushed horizontally with a force of 620N. If the coefficient of friction is 0.20, calculate the acceleration of the box.
April 23, 2014

statistics
A sociologist is interested in the relation between x = numberof job changes and y = annual salary (in thousands of dollars) forpeople living in the Nashville area. A random sample of 10people employed in Nashville provided the followinginformation: x (number of job changes) 4...
April 20, 2014

chem
Given that the density of the supplied vinegar solution in this experiment is 1.025 g/mL, calculate the % acetic acid found in the vinegar sample.
April 15, 2014

physics
but what is the tension of the wire
April 14, 2014

Calculus
ABC Daycare wants to build a fence to enclose a rectangular playground. The area of the playground is 900 square feet. The fence along three of the sides costs \$5 per foot and the fence along the fourth side, which will be made of brick, costs \$10 per foot. Find the length of ...
April 13, 2014

math trigonometry
two office towers are 31 m apart. From the top of the shorter tower, the angle of elevation to the top of the tall tower is 25 degrees . The angle of depression to the base of the taller tower is 31 degrees. Calculate the height of each tower
April 13, 2014

math
two office towers are 31 m apart. From the top of the shorter tower, the angle of elevation to the top of the tall tower is 25 degrees . The angle of depression to the base of the taller tower is 31 degrees. Calculate the height of each tower
April 13, 2014

Chemistry
Calculate the standard cell potential for each of the electrochemical cells? What would the answers be to something like this? If someone could work out the answer I would really appreciate it. My online hw keeps telling me its wrong. 2Ag+(aq)+Pb(s)→2Ag(s)+Pb2+(aq) E&#...
April 12, 2014

Chemistry
Calculate the standard cell potential for each of the electrochemical cells? What would the answers be to something like this? If someone could work out the answer I would really appreciate it. My online hw keeps telling me its wrong. 2Ag+(aq)+Pb(s)→2Ag(s)+Pb2+(aq) E&#...
April 12, 2014

Chemistry
Calculate ΔG∘rxn and E∘cell for a redox reaction with n = 1 that has an equilibrium constant of K = 28? What would the answer be to this? Could someone work this out for me please? ΔG∘rxn = ......kj E∘cell = ......V
April 12, 2014

physics
A cylindrical conductor of radius carries a uniformly distributed current I. Show that the magnetic field within the conductor measured at a distance r from the center is given by the following equation... B= (u0Ir)/2pi a^2
April 12, 2014

Chemistry
Calculate ΔG∘rxn and E∘cell for a redox reaction with n = 1 that has an equilibrium constant of K = 28? What would be the answer to this fine question. How would you do something like this? Thanks :) ΔG∘rxn = ......kj E∘cell = ......V
April 11, 2014

chemistry
Calculate the standard cell potential for each of the electrochemical cells? 2Ag+(aq)+Pb(s)→2Ag(s)+Pb2+(aq) E∘cell......V? 2ClO2(g)+2I−(aq)→2ClO−2(aq)+I2(s) E∘cell......V? O2(g)+4H+(aq)+2Zn(s)→2H2O(l)+2Zn2+(aq) E∘cell......V?
April 11, 2014

trig
Given angle x, where 0 <= x < 360 (degrees), cos(x) is equal to a unique value. Determine the value of to the nearest degree. Justify your answer.
April 11, 2014

trig
How did you get 2x=211 ?
April 11, 2014

trig
Given angle x,where 0 <= x <= 360 (degrees) solve for to the nearest degree. a)cos(2x) = 0.6420 b)sin(x + 20) = 0.2045 c)tan(90 - 2x) = 1.6443
April 11, 2014