Friday
March 27, 2015

# Posts by m

Total # Posts: 996

Chemistry
The decomposition of hydrogen peroxide is first order in H2O2: 2H2O2(aq) → 2H2O(l) + O2(g) Rate = k [H2O2] How long will it take for half of the H2O2 in a 10-gal sample to be consumed if the rate constant for this reaction is 5.6 x 10-2 s-1?
March 5, 2013

Chemistry
Never mind I figured it out Ln(At)=-(.152min-1)(120min)+ln(10) Ln(At)= -18.24+(2.30) Ln(At)=-15.9 e^At=e^-15.9 At= 1.19 x 10^-7 %=1.19 x 10^-7 x 100 =1.19 x 10^-5 % of the isotope
March 5, 2013

Chemistry
I've figured out most of it. I'm not sure how to find the percentage ofd the isotope. Define the half life. The half-life of a radioisotope is found to be 4.55 minutes. If the decay follows first order kinetics, what percentage of isotope will remain after 2.00 hours ...
March 5, 2013

Chemistry
I need to know the kcal/mol. How do I find the kcal/mol??
March 5, 2013

Chemistry
I've figured out the Ea but I'm not sure how to find the kcal/mol The gas reaction N2O5 → 2NO2 + 1/2O2 follows the Arrhenius equation k = Ae(-Ea/RT) where R = 8.314 J K-1 mol-1 and 1 calorie = 4.184J. At the temperature T=273K, k = 3.46 x 10-5 s-1, whereas at T...
March 5, 2013

Chemistry
. For the reaction 2H2(g) + 2NO(g) → N2(g) + 2H2O(g) The observed rate law is Rate =k[NO]2[H2] The mechanisms shown below have been proposed to explain the kinetics of the above reaction Which of the following are acceptable mechanisms? Explain you answer Mechanism I 2H2...
March 5, 2013

Chemistry
I've tried to answer some -The reaction mechanism for a reaction is as follows… Step 1 O3 (g) + NO2 (g)→ NO3 (g) + O2 (g) slow Step 2 NO3 (g) + NO2 (g) → N2O5 (g) fast a. Write the overall reaction equation. b. Identify the molecularity of each step. They ...
March 5, 2013

Chemistry
Given…Overall reaction: 2 NO2 (g) + F2 (g) → 2 NO2F (g) Rate = k[NO2][F2] a. Can this be a single step reaction? b. Postulate a mechanism using experimental data and chemical intuition come up with a mechanism that fits.
March 5, 2013

7th Math
What is the function rule for 2,30 4,15 6,10 10,6 12,5 15,4 30,2
March 5, 2013

Chemistry
First find the moles of HCl by dividing .15/36.45 and then once you find the moles divide that by the liters given which in this case is 8 and that will give you the molarity which you can plug into -log(H+) and that should give you 3.3 as the answer.
March 1, 2013

trig
If cot x = .78, what is tan x?
February 21, 2013

physics
A 0.145-kg baseball pitched horizontally at 27 m/s strikes a bat and is popped straight up to a height of 38 m. If the contact time between the bat and the ball is 2.35 ms, calculate the average force [exerted by the bat on the ball] during contact. [Let the positive axis lie ...
February 19, 2013

chemistry
How do I find mols?
February 17, 2013

chemistry
A solution contains 0.02755 g of a protein in 25.0 mL of solution. The osmotic pressure is 3.22 torr at 298 K. What is the molecular weight of the protein?
February 17, 2013

Chemistry
Lauryl alcohol is obtained from coconut oil and is used to make detergents. A solution of 5.00 g of lauryl alcohol in 100.0 g of benzene freezes at 4.2 oC. What is the approximate molar mass of lauryl alcohol. Refer to the text book for the boiling point of pure benzene. (80 C...
February 17, 2013

Chemistry
Arrange the following aqueous solutions in order of increasing boiling point, explain your answer: 0.120 m glucose (C6H12O6), 0.05 m LiBr, 0.05 m Zn(NO3)2. Using data the boiling point constants given in the test book, calculate the boiling points of each of the above aqueous ...
February 15, 2013

Chemistry
What is the % mass of 12 M hydrochloric acid. Density of 12 M hydrochloric acid solution is 1.18 g/mL and the density of water is 1.00 g/mL
February 15, 2013

Chemistry
How many grams of sulfuric acid is in 25.0 g of 8.00 % H2SO4 solution?
February 15, 2013

Math
Find the intergral of (1+x)/sqrt(3-x^2)
February 13, 2013

Calculus
Find the intergral of (1+x)/sqrt(3-x^2)
February 13, 2013

chemistry
anyone help me . .what volume of concentrated HCL solution whoch is 36% by mass and has a density of 1.179 g/ml , should be used to make 4.7 L of hcl solution with a pH of 1.8 ?
February 13, 2013

Chemistry
Why don't you tell me how you approached the problem and then I can see for myself. There's a general method of doing this so I figure you'd know and get some kind of answer. My question wasn't if you could check my work; my questions are clearly indicated with...
February 10, 2013

Chemistry
The first-order rate constant for the decomposition of N2O5, 2N2O5(g) --> 4NO2(g) + O2(g), at 70 degrees C is 6.82 x 10^-3 s^-1. Suppose we start with .0208 mol of N2O5(g) in a volume of 2.2 L. How many minutes will it take for the quantity of N2O5 to drop to .014 mol? I&#...
February 10, 2013

physics
A patient has a far point of 29.2 cm and a near point of 24.2 cm. What power (in diopters) should be prescribed to correct the patient's vision using: (b) glasses which are worn 0.5 cm away from the patient's eyes?
February 7, 2013

physics
A patient is going to be prescribed bifocals which will be 2.50 cm from the eye. The prescribed powers (in diopters) for the bifocals are +1.60 and -0.40, and these bifocals give the patient normal vision. (a) Without the bifocals, what is the patient's near point? cm (b) ...
February 7, 2013

Chemistry
Explain the following phenomena in terms of intermolecular forces. Determine the major type of forces between the molecules. a) You can't clean grease off you hand with water only b) Pancake syrup is more dense than olive oil. Please provide the structure of both in your ...
February 1, 2013

English
I must combine the following sentences in the most effective way. Is my answer correct? Sentences: 1. He didn't cover his vehicle with the traditional camouflage. 2. He covered it with his own drawings. My answer(s) - Not sure which is the best way: He didn't cover his...
January 24, 2013

English
I must improve the organization of these four sentences of a paragraph in the most effective way. Is my answer correct? Sentences: 1. The reader has probably figured out that the boy named Walter was Walter Elias Disney. 2. During his lifetime Disney and his staff created 18 ...
January 24, 2013

English
Question: How can I rewrite this sentence to maintain the 3rd person academic tone? Is my answer correct? 1. You have probably figured out that the boy named Walter was Walter Elias Disney. My answer: One has probably figured out that the boy named Walter was Walter Elias Disney.
January 24, 2013

English
Question: How can I rewrite this sentence to maintain the 3rd person academic tone? Is my answer correct? 1. You have probably figured out that the boy named Walter was Walter Elias Disney. My answer: One has probably figured out that the boy named Walter was Walter Elias Disney.
January 24, 2013

english
I must combine the following sentences in the most effective way. Is my answer correct? 1. Walter loved animals. 2. He especially loved watching them in the forest near his Missouri home. My answer: Walter loved animals, especially watching them in the forest near his Missouri...
January 24, 2013

english
I am to create a timeline that illustrates the history of children's literature in western culture using five key milestones of children's literature. Can you please tell me if these milestones I have chosen would be correct to use: 1-invention and development of ...
January 21, 2013

physics
A lamp which is 9.0 cm tall is in front of a concave mirror which has a focal length of 53.0 cm. (a) How tall is the lamp's image if the lamp is a distance of 26.5 cm from the mirror (include sign if negative)? (b) How tall is the lamp's image if the lamp is a distance...
January 17, 2013

chemistry
223.6L
January 7, 2013

Social Studies - URGENT
Is 4 character of place?
December 16, 2012

Social Studies - URGENT
1. Movement 2. Character of Place 3. Movement 4. Region 5. Region
December 16, 2012

Social Studies - URGENT
Using the five themes of geography, which theme best illustrates each statement: Location, character of place, human-environment interation, movement or region. 1. Islam spread to Eastern Europe from Southwest Asia 2. The Scandinavian countries share common influences from ...
December 16, 2012

math
The number of patients treated at Dr. Artin’s dentist office each day was recorded for nine days. These are the data: 6, 6, 6, 5, 5, 6, 5, 6, 5. Find the mean, median, mode, and range of the data. If necessary, round to the nearest tenth
December 1, 2012

Physics
A 17kg child slides down a 2.7m -high playground slide. She starts from rest, and her speed at the bottom is 1.8 m/s. What is the change in the thermal energy of the slide and the seat of her pants?
November 28, 2012

Physics
A car is traveling at 10 m/s. By what factor does the car's kinetic energy increase if its speed is doubled to 20 m/s?
November 28, 2012

Physics
Part A: A cardinal (Richmondena cardinalis) of mass 4.50×10^−2 kg and a baseball of mass 0.142 kg have the same kinetic energy. What is the ratio of the cardinal's magnitude p(c) of momentum to the magnitude p(b) of the baseball's momentum? Part B: A man ...
November 28, 2012

math
pedro swam some laps in the pool and then swam 2 more.... algebraic expression
November 27, 2012

math
estimate each quotient 246.78/83?
November 27, 2012

science
what happens to a liquid when it releases enough energy?
November 27, 2012

Chemistry
Can someone help draw/explain the Lewis Dot Structure for OPBr3. I've tried different things, but none of them seem to work.
November 19, 2012

spelling
eioubdhrs
November 13, 2012

Math
In a lightning storm, the number of seconds between the flash and the bang varies directly with the number of miles you are from the lightning. It takes 15 seconds for the thunder sound to reach you from lightning that is 3 miles away. If the thunder sound reaches you in 1 ...
November 4, 2012

Math
When you scuba dive, the added pressure due to the water varies directly with your depth. At 20 feet, the added pressure is about 9 pounds per square inch. a) If an amateur diver can safely stand an added pressure of 30 (psi), how deep could he dive? b) A sunken submarine lies...
November 4, 2012

Chemistry
Why is energy released in order to react two atoms to form a compound? For instance the reaction between sodium metal and chlorine gas is highly exothermic and produces NaCl(s). Meanwhile when an atom loses an electron, it will be endothermic. Can someone try to explain this ...
November 4, 2012

Math
The distance between two towns on a map varies directly with the actual distance between the towns. Seven and a half inches on the map represents 150 miles. What is the actual distance represented by 11 inches on the map?
November 4, 2012

Math
An 8-ounce weight stretches a spring 10 cm. How much weight will stretch the spring 15 cm?
November 4, 2012

Chemistry
The answer is actually 1.
November 4, 2012

MATH
In a study 42% of adults questioned reported that their health was excellent. A researcher wishes to study the health people living close to a nuclear power plant. Among 13 adults randomly selected from this area, only 3 reported that their health was excellent. Find the ...
October 30, 2012

english
what are the two formal fallacies? My answer- fallacy of denying the antecedent and fallacy of affirming the consequent. I don't know if this is correct.
October 21, 2012

Chemistry: Partial Pressure
No, I haven't.
October 18, 2012

Chemistry: Partial Pressure
I tried working it out by finding the moles of CO and then dividing that over the total moles and multiplied by .640atm, but I didn't get the right answer.
October 18, 2012

Chemistry: Partial Pressure
A mixture of 0.166 moles of C is reacted with 0.117 moles of O2 in a sealed, 10 L vessel at 500 K, producing a mixture of CO and CO2. The total pressure is 0.640 atm. What is the partial pressure of CO? Please provide a step by step explanation with the answer so I can ...
October 18, 2012

englsh
The following arguments contain various kinds of fallacies. Evaluate each and identify the fallacy using the matching list 1. How can Clinton be leading this country? He's a draft-dodging, pot-smoking womanizer! 2. Michael Jordan wore that brand, so those must be the best ...
October 18, 2012

english
The following arguments contain various kinds of fallacies. Evaluate each and identify the fallacy using the matching list at bottom. 1. We can recognize that athletes who participate in sports must be given special consideration in our grading system, or we can let the ...
October 17, 2012

Evolutionary Bio
How would you differentiate a monophyletic from a polyphyletic and paraphyletic? I know the definition but can someone provide me with an exmaple and an explanation for it so I can understand better? That would be greatly appreciated!
October 15, 2012

Evolutionary Bio
Is Amborella considered a magnoliid, monocot, or eudicot and why?
October 15, 2012

English-Ms. Sue please
hypothetical syllogisms can have two valid and two invalid structures. The two valid structures are affirming the antecedent or modus ponens and denying the consequent or modus tollens. The two invalid structures or fallacies are denying the antecedent and affirming the ...
October 11, 2012

english
hypothetical syllogisms can have two valid and two invalid structures. The two valid structures are affirming the antecedent or modus ponens and denying the consequent or modus tollens. The two invalid structures or fallacies are denying the antecedent and affirming the ...
October 11, 2012

English
I am a bit stumped here. Working on syllogisms. To be a valid syllogism, the conclusion must be proven by the reasons. We are to decide if te following are valid or invalid. 1. All zebras are striped animals. No zebras are polar bears. Therefore, no polar bears are striped ...
October 10, 2012

Chemistry
World energy supplies are often measured in the unit of quadrillion British thermal units (10^12 btu), generally called a "quad." In 2015, world energy consumption is projected to be 5.81*10^17kJ. Current annual energy consumption in the United States is 99.3 quads. ...
October 7, 2012

Chemistry
World energy supplies are often measured in the unit of quadrillion British thermal units (10^12 btu), generally called a "quad." In 2015, world energy consumption is projected to be 5.81*10^17kJ. Current annual energy consumption in the United States is 99.3 quads. ...
October 7, 2012

english
Hot to unscramble rdntcioiya
October 2, 2012

Evolutionary Bio
What is Ghost of selection past?
October 1, 2012

Chemistry
What is the net ionic equation of reaction of MgCl2 with NaOH? I got the equation and then balanced it and then omitted the spectator ions and ended up with: Mg(OH)2(aq)--->Mg(OH) (s) I wanted to confirm to see if that was correct, thanks.
September 26, 2012

Chemistry
I was able to figure out that NaHCO3 was the limiting reagent. And then I got that there was .7596 grams of CO2 by converting the 1.45g of NaHCO3. I tried to use 1.45 NaHCO3 to figure it out but, I didn't get the right answer. My work: 1.45g NaHCO3(1mol NaHCO3/83.998g ...
September 16, 2012

Chemistry
The fizz produced when an Alka-Seltzer® tablet is dissolved in water is due to the reaction between sodium bicarbonate (NaHCO3) and citric acid (H3C6H5O7): In a certain experiment 1.45g of sodium bicarbonate and 1.45g of citric acid are allowed to react. How many grams of ...
September 16, 2012

Chemistry
Octane has a density of 0.692 at 20degree C . How many grams of O2 are required to burn 17.0gal of C8H18 ? Step-by-step explanation much appreciated with as much detail as possible so I can understand. Thanks!
September 16, 2012

chemistry
How many moles of ammonium ions are in 8.794g of ammonium carbonate? I've tried this multiple times but some reason, I can't quite get the answer. If someone can show me step-by-step how to go about this problem, I'd really appreciate it.
September 16, 2012

Chemistry
A student found that her mixture was 15 percent NH4cl 20 percent NaCl and 75 percent Sio2 Assuming her calculations are correct what did she most likely do incorrectly in her experiment?
September 4, 2012

Chemistry
Given 1.7 g of hydrobromic acid (48%) calculate the number of mL. (MW HBr: 80.91 g/mol, density: 1.49 g/mL)
September 3, 2012

math
I didn't write the question- doesn't make much sense
August 27, 2012

math
A ball bounces back .06 of its height on every bounce. If a ballistic dropped from 200feet, how high does it bounce on the fifth bounce? Round to nearest tenth.
August 27, 2012

HEALTH
I know that A is wrong.
August 11, 2012

Physics
A 0.3 kg ball strikes a wall head on and then rebounds straight back. The initial speed was 10.0 m/s and the speed after it rebounds was 1.9 m/s. What was the magnitude of the total impulse on the ball during the collision in N*s?
July 9, 2012

Physics
Two objects A and B are involved in a totally elastic collision The mass of A is 8.8 kg and the mass of B is 0.5 kg. The velocity of A is 4.5 m/s and the velocity of B is 0 m/s. If they collide elastically, what will be the final velocity of A in m/s?
July 9, 2012

Physics
Two balls are involved in a completely inelastic collision. The first ball has a mass of 0.25 kg and an initial velocity of 9.27 m/s in the x-direction The second ball has a mass of 0.50 kg with an initial velocity of 2.61 m/s in the -x-direction. What is the speed of the two ...
July 9, 2012

Beginning Spanish-SraJMcGin
I am sorry I posted this a few moments ago with the wrong name attached at the top I apologize. I had these 2 questions that went with my earlier question. Lee cada situación a continuación y, según el contexto, indica si el se o nos significa each other o...
June 14, 2012

beginning spanish-SraJMcGin
I put at the end that I thought the answers to 1,2,3 were yes and 4 was no
June 14, 2012

beginning spanish
The assignment is to identify if "SE" or "NOS" is next to a REFLEXIVE verb/action (the subject(s) is(are) transmitting the action to himself (each other)) . Lee cada situación a continuación y, según el contexto, indica si el se o nos ...
June 14, 2012

Physics
An airplane flying at 82km/hr at 30 degrees east of north encounters a 40km/hr wind due west. What is the speed of the plane relative to the ground?
June 12, 2012

social studies
Which of the following hispanic countries has suffered an invasion by the U.S.? A) Spain, Argentina, Puerto Rico B) Cuba, Mexico, Nicaragua C) Ecuador, Peru, Colombia I think the answer is B am I correct?
June 1, 2012

physics
a body falls freely from rest
May 20, 2012

beginning spanish
I am to indicate the subject and object of each verb in the sentences. 1. no la quiere para nada. subject- la object- is none 2. lo ve todos los dias. subject- lo object- todos los dias 3. los obedece subject- los object- is none can you tell me if I am correct
May 16, 2012

Physics
A magnetic field is perpendicular to the plane of a single-turn circular coil. The magnitude of the field is changing, so that an emf of 0.63 V and a current of 2.7 A are induced in the coil. The wire is then re-formed into a single-turn square coil, which is used in the same ...
May 14, 2012

beginning spanish
the question is : que estudias? I am to respond that I am a history major. Am I correct to say Estudio historia
May 7, 2012

chem ll
Don't understand where to plug everything in.
April 30, 2012

spanish
te question is Ella se ____ Julia. We were to pick between llama, llamas, and nombre. I think the answer is llama but a little hesitant on that
April 22, 2012

Physics (Waves)
You have 27 tuning forks that oscillate at close but different frequencies. What are the (a) maximum and (b) minimum number of different beat frequencies you can produce by sounding the forks 2 at a time, depending on how the frequencies differ? *I KNOW HOW TO DO B, I GOT THAT...
April 20, 2012

science
My son had this assignment and it is totally confusing to me. This is the info provided: 4.5-V lightbulb and 3 batteries that are 1.5 V each Knowing Ohm's law: voltage (in volts) =current (in amps) x resistance (in ohms) or V=IR. Determine in which circuit the voltage was ...
April 17, 2012

physics
Just as a car tops a 51 meter high hill with a speed of 85 km/h it runs out of gas and coasts from there, without friction or drag. How high, to the nearest meter, will the car coast up the next hill?
April 14, 2012

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