Monday
March 2, 2015

Posts by danny


Total # Posts: 734

chemistry
One of the ways to produce iron is to take iron(II) oxide and react it with carbon monoxide to get pure iron and carbon dioxide. The reaction is FeO(s) + CO(g) = Fe(s) + CO2(g). What is the partial pressure of CO2(g) if 2.00 atm of CO and excess iron(II) oxide are used to ...
February 28, 2015

chemistry
Lead iodide is a relatively insoluble compound. It can dissolve from the solid phase into the aqueous phase with a Keq of 0.00027. If the concentration of lead iodide in the aqueous phase 0.125 M, then: a. we need more information to determine the progress of the reaction. b. ...
February 28, 2015

chemistry
Equilibrium is: a dynamic condition in which the concentration of the reactants is equal to the concentration of the products. a static condition in which the concentration of the reactants is equal to the concentration of the products. a static condition in which the rate of ...
February 28, 2015

Science check
Water in the upper zones of the ocean will have more oxygen than water in deeper zones. true or false i think true.
February 27, 2015

math
6528
February 27, 2015

physics
PART ONE: A charge of 4.70μC is at the origin and a second charge of −2.85μC is on the positive x-axis 1.08 m from the origin. Find the magnitude of the electric field at a point P on the y-axis 0.640 m from the origin. The value of the Coulomb constant is 8.99...
February 26, 2015

chemistry
increase the temperature ?
February 25, 2015

chemistry
The following equilibrium exists in a closed container: N2(g) + O2(g) = 2NO(g), ΔH = +181 kJ/mol. Which of the following perturbations would favor the formation of NO(g)? (practice MCAT question from The Princeton Review MCAT Science Workbook, 2009 edition) increasing the...
February 25, 2015

chemistry
Suppose you have the following reaction at equilibrium: N2(g) + 3H2(g) = 2NH3(g), ΔH = −22 kcal/mol What changes are expected to occur if the temperature of the system was decreased. You may select multiple answers. The concentration of NH3(g) would decrease The ...
February 25, 2015

chemistry
1) C2H2O4(aq) = H+ (aq) + C2HO4- (aq); Keq = 6.5E-2 2) C2O42- (aq) + H+ (aq) = C2HO4- (aq); Keq = 1.64E+4 then what is the equilibrium constant for the following reaction: C2H2O4(aq) = 2H+ (aq) + C2O42- (aq)? Keq = 1070 Keq = 227 Keq = 2.21E-4 Keq = 3.96E-6 Keq = 6.30E-3
February 25, 2015

chemistry
The pollutant NO is formed in diesel engines. The reaction fixes atmospheric nitrogen with oxygen to form NO. The reaction is: N2(g) + O2(g) = 2NO(g). If the equilibrium constant for this reaction at elevated temperatures is 5.60E-11, then what is the partial pressure of NO ...
February 25, 2015

chemistry
How is the reaction quotient used to determine whether a system is at equilibrium? The reaction is at equilibrium when Q > Keq. At equilibrium, the reaction quotient is undefined. The reaction quotient must be satisfied for equilibrium to be achieved. The reaction is at ...
February 25, 2015

chemistry
Which of the following statements is not true? 1.Chemical equilibria are examples of reversible processes. 2.When multiple reaction steps are in equilibrium, then the equilibrium constant for the net reaction is the product of the individual reactions. 3.The equilibrium ...
February 25, 2015

Calculus Physics
Nevermind I figured it out
February 19, 2015

Calculus Physics
A 1559-kg car moves at 15.0 m/s. What is the magnitude of the horizontal net force needed to bring the car to a halt in a distance of 50.0 m?
February 19, 2015

Calculus Physics
Thanks Steve
February 19, 2015

Calculus Physics
That's F(t)=5sqrt(t)
February 19, 2015

Calculus Physics
A particle is subject to a time-dependent force: F(t)=5t√. If the particle's mass is 7 kg, what will its velocity be at t=6.7 seconds, assuming its initial velocity at t=0 is equal to 0.
February 19, 2015

Calculus Physics
A particles with mass 3.7 kg moves in the x direction according to the following function: x(t)=−7+4t+3t2−4t3. (the units of each coefficient are meters, and time is measured in seconds). At time t=7.8, what is the net force acting on the particle?
February 18, 2015

Calculus Physics
A box and one force vector, F1 is shown. F1 = + 10 N. If the mass of the box is 3 kg, what is the magnitude and direction of a force, F2, that would need to be applied if the box was to have an acceleration of + 2 m/s 2 in the horizontal direction. (Indicate direction by ...
February 18, 2015

physics
38. A rock of mass 0.400 kg is released from the surface and sinks in the ocean. As the rock descends it is acted upon by three forces: gravity, buoyancy, and drag. The buoyancy is an upward force equal to half its weight. Drag from the water can be modeled by F = kv, where k...
February 17, 2015

physics
21. A traffic signal of mass 25.0 kg is suspended by two cables as shown in the diagram below. Solve for the tension in each cable each of the following scenarios: (a) θ1 = θ2 = 20.0°, and (b) θ1 = 20.0°, θ2 = 30.0°.
February 17, 2015

chemistry
Two-stroke motor boat engines emit a large amount of partially burned fuel into the water. One of the more common chemicals is phenanthrene . The degradation half-life of phenanthrene is about 7.30 days in clear surface waters. If a motor boat emits 97.0 g of phenanthrene ...
February 15, 2015

chemistry
Based on reaction kinetics, which of the following pairs of reactions and reaction rate equations represent elementary reactions? You may choose more than one reaction. Ti + 2Cl2 = TiCl4 Rate = k[Ti][Cl2] 2SO2 + O2 = 2SO3 Rate = k[O2][SO2]2 Na2S + CuSO4 = CuS + Na2SO4 Rate = k...
February 14, 2015

chemistry
The activation energy of a reaction is typically determined by calculating the rate constant for the reaction at two temperatures and then manipulating the Arrhenius equation. If you determine the reaction rate constants for a particular reaction to be 0.0650 /s at 25.0 C and ...
February 14, 2015

chemistry
Suppose 100 moles of a chemical is spilled into a lake. After 15.0 days, the total amount of the chemical in the lake 3.50 moles. Assuming that the reaction followed first order kinetics and no chemical was lost due to advection or volatilization, then what is the rate ...
February 14, 2015

chemistry
Radioactive waste is difficult to dispose of due to the long time periods needed before the radiation effectively disappears. The US protocol is to store the waste for 10 half-lives of the material after which the waste is no longer considered radioactive. After this time, ...
February 14, 2015

chemistry
In which of the following reactions is ΔE closest in value to ΔH? HNO3(aq) + Na2(CO3)(aq) = NaNO3(aq) + H2O(l) + CO2(g) KClO3(s) = KCl(s) + (3/2)O2(g) HCl(aq) + NaOH(aq) = H2O(l) + NaCl(aq) Na(s) + H2O(l) = NaOH(aq) + (1/2)H2(g)
February 14, 2015

chemistry
If the breakdown half-life of a pesticide applied to a farmer’s field is 3.50 days, then what is the rate constant for this reaction? Assume the degradation reaction follows first order kinetics. The units are 1/d.
February 14, 2015

chemistry
Ethylene gas (C2H2) can be formed from the reaction of calcium carbide (CaC2) with water. What is the reaction rate if 14.2 grams of ethylene gas are produced over 4.00 seconds? The units are mol/s.
February 14, 2015

physics
REALLY NEED HELP WITH THIS PLEASE. One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1....
February 8, 2015

physics
One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^24 for Part A. i need help...
February 8, 2015

Physics
no the answer is incorrect. im so confused @bob
February 8, 2015

Physics
One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^24 for Part A. i need help...
February 8, 2015

chemistry
Calculate the change in Gibb’s free energy when 1.63 moles of sodium metal react with excess chlorine gas to form sodium chloride . Assume standard conditions. The ΔG values can be found in your textbook. The units for the answer are kJ
February 7, 2015

chemistry
White phosphorus (P4) was used for a long time in military incendiary bombs and ordnances. White phosphorus reacts with oxygen in the air and burns at very high temperatures, so it sets things on fire. Calculate the change in enthalpy resulting from a 25.0 pound white ...
February 7, 2015

chemistry
Calculate the change in free energy when you drop 4.70 g of calcium metal into a beaker containing excess water so that Ca(OH)2(s) and H2 gas are formed? The delta-G values you need are in your textbook. The units are kJ.
February 7, 2015

chemistry
Which of the following processes is entropy increasing in the local system? You may select multiple processes. Combination reactions where two reactants join to make a single product. a system with increasing molecular motion cooling a six-pack of beer by putting it in a ...
February 7, 2015

chemistry
Which of the following reactions will be spontaneous at standard state? Not all the reactions are balanced, so make sure they are balanced first. The ΔG of formation data can be found in an appendix in your text book. You may select multiple answers. Any reaction with ...
February 7, 2015

chemistry
ΔS is positive for which one of the following reactions? Ag+(aq) + Cl- (aq) = AgCl(s) N2(g) + 3H2(g) = 2NH3(g) CaO(s) + CO2(g) = CaCO3(s) 2SO3(g) = 2SO2(g) + O2(g) H2O(l) = H2O(s)
February 7, 2015

chemistry
Suppose you have a reaction that has a ΔH of +80 kJ and a ΔS of 215 J/K. At what temperature will this reaction change from being not spontaneous to spontaneous? 31 C 99 C -18 C 25 C 53 C
February 7, 2015

Physics
huihillll
February 5, 2015

chemistry
Given the following values of ΔH, ΔS and T, calculate ΔG (in kJ). The values are: ΔH = 23.0 kJ, ΔS = 125 J/K, and temperature = 85.0 C.
February 5, 2015

chemistry
Given the following values of ΔH, ΔS and T, calculate ΔG (in kJ). The values are: ΔH = -95.0 kJ, ΔS = 217 J/K, and temperature = 160 C.
February 3, 2015

chemistry
How many core electrons are there in a ground state phosphorus atom?
February 3, 2015

chemistry
Given: Equation #1: 4NH3(g) + 5O2(g) = 4NO(g) + 6H2O; ΔH of reaction = -1170 kJ Equation #2: 4NH3(g) + 3O2(g) = 2N2(g) + 6H2O; ΔH of reaction = -1530 kJ Then what is the ΔH of reaction for: N2(g) + O2(g) = 2NO(g)? Enter a numerical value below and be sure to ...
January 31, 2015

chemistry
Calcium carbide (CaC2) reacts with water to form acetylene (C2H2) gas and calcium hydroxide (Ca(OH)2). If the ΔH for: CaC2(s) + 2H2O(l) = Ca(OH)2(s) + C2H2(g) is -127 kJ, then what is the enthalpy of formation for calcium carbide? The ΔH of formation for H2O(l), Ca(...
January 31, 2015

chemistry
Suppose that your morning shower is 7 minutes long and uses 4 gallons of water per minute that is a nice 102 F in temperature. How much energy (kJ) must be used to heat the water for your shower if the water coming into your house is at 60 F? The heat capacity of water is 4....
January 31, 2015

chemistry
Suppose you add 92 ml of dilute acid to 46 ml of water. Both the water and acid were at room temperature (22 C) before being mixed. The temperature of the solution increased to 39 C. How much energy (in kJ) was released by the dissolution of the acid if the specific heat ...
January 31, 2015

chemistry
In the reaction below, ΔH°f is zero for ___________. Ni(s) + 2CO(g) + 2PF3(g) = Ni(CO)2(PF3)2(l) Ni(s) CO(g) Ni(CO)2(PF3)2(l) both CO(g) and PF3(g) PF3(g)
January 31, 2015

chemistry
The enthalpy change for the following reaction is -483.6 kJ: 2H2(g) + O2(g) = 2H2O(g) Therefore, the enthalpy change for the following reaction is _______ kJ: 4H2(g) + 2O2(g) = 4H2O(g)
January 31, 2015

chemistry
What is the specific heat capacity of ethanol (C 2H 6O) if a 18.3 g sample increased 12.3 C upon the addition of 553.0 J? The units are J/(g ·K)
January 31, 2015

chemistry
The radiator in your car uses either water or ethylene glycol (anti-freeze) to remove heat from the engine and dissipate it to the outside air. If the water recirculation rate is 17.0 kg per minute of water and the water temperature leaving the engine and entering the ...
January 31, 2015

chem
What is the specific heat capacity of aluminum if a 8.4 g sample increased 21.1 C upon the addition of 159.0 J? The units are J/(g ·K). q=cpxMxT is the equation my answer i got is 401.65 is that right bec i feel thats wrong
January 29, 2015

chemistry 116
What is the specific heat capacity of aluminum if a 8.4 g sample increased 21.1 C upon the addition of 159.0 J? The units are J/(g ·K). q=cpxMxT is the equation my answer i got is 401.65 is that right bec i feel thats wrong
January 29, 2015

chem
The value for ΔH° for the reaction below is -72 kJ. How many kJ of heat are released when 1.0 mol of HBr is formed in this reaction? H2(g) + Br2(l) = 2HBr(g)
January 28, 2015

physics
What is the mass of 5.00L of pure water?
January 28, 2015

physics
A typical multivitamin tablet can contain 2.00mg of vitamin B2 (riboflavin), and the RDA is 0.0030 g/day. How many such tablets should a person take each day to get the proper amount of this vitamin, assuming that he gets none from any other sources?
January 28, 2015

chemistry 116
The thermite reaction demonstrated in class requires high temperatures to start the reaction. A simple open flame is not enough to start the reaction. Once the reaction is going, then it generates enough heat to keep the reaction going. According to the literature on thermite...
January 28, 2015

chemistry 116
A 36.0 g piece of copper at 130.0 C is placed in 50.0 g of water at 20.0 C. What is the temperature (in C) of the water once the system reaches equilibrium? The molar heat capacity of copper is 24.5 J/(mol·K). The specific heat capacity of water is 4.18 J/(g·K...
January 27, 2015

chem
so i did 17000 x4.18x(86-46)=284 is that what you meant
January 27, 2015

chem
The radiator in your car uses either water or ethylene glycol (anti-freeze) to remove heat from the engine and dissipate it to the outside air. If the water recirculation rate is 17.0 kg per minute of water and the water temperature leaving the engine and entering the ...
January 27, 2015

chem
thank you i got 801.1678 is that correct
January 27, 2015

chem
If you burn 13.7 g of methane (CH4) burns in oxygen, then 686 kJ is evolved. What is the amount of heat produced per mole of methane burned?
January 27, 2015

chem
Suppose you mix hydrogen, CCl4, CO2, NO2 and fluorine gases together and allow them to reach an equilibrium temperature. Which gas has the SLOWEST average molecular (or atomic) speed?
January 26, 2015

History
Really far north it would be september?
January 21, 2015

History
What time of year does snow come to the far north?
January 21, 2015

Math
I'm less than a hundred, the sum of my digits 17, I am a even number
January 15, 2015

chemistry Drbobz222
How do i convert mols CaCl2 to AgCl
January 12, 2015

biology
What role does the lilac flower play in its natural ecosystem? What is its niche in the food web Are there any ecological issues surrounding the lilac flower(e.g. are its populations decreasing, is it spreading uncontrollably..)
December 23, 2014

Physics
is there a site that can also help me
December 20, 2014

Physics
my question is: What is the purpose of the resonator of a stringed instrument
December 20, 2014

Physics
What is the purpose of the resonator stringed instrument
December 20, 2014

History
July 4, 1776
December 16, 2014

chemistry
What is the final concentration of 35.7mL of 52.0% m/m solution that is diluted to 65.9ml? i am not sure how to caluclate this... but i know the formula is C1V1=C2V2
December 16, 2014

chemistry
What is the mass of 4.3 × 10 to the power of15 atoms of nickel (Ni)?
December 7, 2014

Chemistry
I don't understand.. under Sam
November 21, 2014

Chemistry
A sample of toluene, C7H8 has a mass of 74.5 g. How many moles of benzene does it contain? How many molecules does the sample contain? How many carbon atoms does it contain?
November 21, 2014

physics
The block of mass 1.43443 kg has an acceleration of 3.6 m/s^2 as shown. What is the magnitude of F? Assume the acceleration due to gravity is 9.8 m/s^2 and the surface is frictionles
November 13, 2014

science
A 5.0 kg model vehicle travelling at 14 m/s experiences a rocket boost of 85 N ( in the direction of motion) for 20 s What is the resulting speed? The answer is 350 but i dont know how to get to that answer
November 6, 2014

Math
I dont get this eather i really would like to know how people get the answer
November 5, 2014

chemistry
Complete and balance the following reactions, where applicable. If no reaction occurs, write N.R. Li + H2O ---> KCI + F2 ---> Au + HNO3 ----> CI2 + NaF ---> Li + Fe(NO3)3 --->
November 3, 2014

chemistry
Why is it important to make sure that the volume of water and the starting temperature are the same in each trial ?
October 28, 2014

physics
A boy runs 18.4 blocks North, 12.9 blocks Northeast, and 19.7 blocks West. a)Determine the length of the displacement vector that goes from the starting point to his final position. b)Determine the direction of the displacement vector. Use counterclockwise as the positive ...
October 16, 2014

physics asap!!! thank you
A boy runs 18.4 blocks North, 12.9 blocks Northeast, and 19.7 blocks West. a)Determine the length of the displacement vector that goes from the starting point to his final position. b)Determine the direction of the displacement vector. Use counterclockwise as the positive ...
October 16, 2014

physics
The pilot of an aircraft wishes to fly due west in a 50.0 km/h wind blowing toward the south. The speed of the aircraft in the absence of a wind is 228 km/h. a) How many degrees from west should the aircraft head? Let clockwise be positive. Answer in units of degrees. b) What ...
October 15, 2014

Math
Figure it out its hw so stop searching it up
October 7, 2014

Chemistry
A sprinter must average 24.0 mi/h to win a 100-m dash in 9.30 s. What is his wavelength at this speed if his mass is 84.5 kg?
October 5, 2014

physics
Cameron kicks a football with an initial vertical velocity of 18.5 m/s and an initial horizontal velocity of 18 m/s and there is a flight time of approximately 2.0 s. Will the field goal travel far enough to make the field goal from 29 m away (if the ball is high enough to ...
September 12, 2014

Physics
How long is Mayra, a ballerina, in the air when she leaps straight up with a speed of 1.23 m/s?
September 11, 2014

Algebra 2
A+B
May 19, 2014

Algebra 2
Has to be 2.
May 19, 2014

Algebra 2
4.
May 19, 2014

Algebra 2
or 3 i think?
May 19, 2014

Algebra 2
c.
May 19, 2014

Algebra 2
Amanda surveyed 20 juniors and seniors at Delamar high school to find the number of hours per week they spend working at part-time jobs. Her results are shown below. Juniors: 20,10,20,10,15,0,0,10,20,15 Seniors: 20,20,10,10,0,0,0,10,0,10 which statement about the data is true...
May 19, 2014

Chemistry
If 689000 J of energy are added to 4.00 L of water at 284 K, what will the final temperature of the water be? Answer in units of K
March 19, 2014

Chemistry
Determine the specific heat of a material if a 34.7 g sample absorbed 45.2 J as it was heated from 293 K to 318 K. Answer in units of J/g · K Your answer must be within ± 2.0%
March 19, 2014

chemistry
Calculate the H3O+ concentration present in water under the following conditions. Enter your answer in scientific notation. a. [OH-] = 2.8 x 10-7 M b. [OH-] = 8.8 x 10-3 M c. [OH-] = 2.4 x 10-11 M everytime I do the problem In the calculator I get system error someone please ...
March 19, 2014

Chemistry
Calculate the pH of a solution in which a. [H3O+] = 7.8 x 10-7 M pH = b. [H3O+] = 5.1 x 10-6 M pH = c. [H3O+] = 6.1 x 10-5 M pH = d. [H3O+] = 9.3 x 10-4 M pH = I get 8.1 9.5 9.1 6.7 but its wrong please someone help!
March 19, 2014

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