Thursday

April 17, 2014

April 17, 2014

Total # Posts: 902

**College Chemistry (DrBob222)**

Thank you! You are legendary!

**College Chemistry (DrBob222)**

The decomposition of HCO2H follows first-order kinetics. HCO2H(g) CO2(g) + H2(g) The half-life for the reaction at a certain temperature is 44 seconds. How many seconds are needed for the formic acid concentration to decrease by 73%?

**chemistry - (Dr. Bob222)**

No, they did not provide any reaction for this problem. If I'll find the solution, I'll post it here. Thank you for your help.

**chemistry - (Dr. Bob222)**

I did that and but I got 1.52 mol/L rather 0.97 (as the answer key provides it)

**chemistry - (Dr. Bob222)**

The rate constant for a second order reaction has the value of 2.5 x 10–3 L·mol–1·s–1. If the initial concentration of reactant is 3.5 mol·L-1, what will be the molar concentration of the reactant after 2.5 minutes?

**Chemistry - Science (Dr. Bob222)**

I have calculated K1 and K2 by dividing initial rate to initial concentration [A2], and I solved for Ea but for some reason I don't get the right answer, (which is 10.2KJ)

**Chemistry - Science (Dr. Bob222)**

Consider the kinetic data given in the table below for the first order reaction: What is the value of the activation energy? A_2_--> 2A Expt. Initial [A2] Temp. Initial Rate mol/L (°C) [A2]·s–1 1 0.10 100 1.2 x 10–3 2 0.20 200 4.8 x 10–3 3 0.15 ? 4...

**Chemistry - Science (Dr. Bob222)**

Consider the kinetic data given in the table below for the first order reaction: What is the value of the activation energy? A_2_--> 2A Expt. Initial [A2] Temp. Initial Rate mol/L (°C) [A2]·s–1 1 0.10 100 1.2 x 10–3 2 0.20 200 4.8 x 10–3 3 0.15 ? 4...

**chemistry**

a 0.0500 mol sample of a nutrient substance is burned in a bomb calorimeter containing 2.00 x 10^2g H2O. If the formula weight of this nutrient substance is 114g/mol, what is the fuel value (in nutrient Cal) if the temperature of the water increased 5.70C

**Math**

Use synthetic division to determine which pair of integers provide both a lower and an upper bound for the zeros of f(x)= x^5-2x^4-25x^3+50x^2+144x-290 PLEASE SHOW WORK!!!

**Subtracting Fractions with like Denominators**

If Lori's neighbor gave her sixths eighths cup of milk, would she then have enough milk to make her 2 pancakes?

**french **

Do this sentence is direct or indirect je vais voir mes cousins

**Physics**

if you throw a 0.2 kg ball straight up at 8 m/s how high will it go

**physics **

What are the principles behind seatbelts and air bags that make passengers safer in a collision?

**physics **

If a motorboat travels 25km/h towards the sea, down a river whose velocity is 4km/h what is the boats velocity related to the shore? A, 21 km/h B, 29km/h C, 25 km/h D, 4 km/h

**physics**

if an airplane is traveling at 550 km/h into a head wind with a velocity of 40km/h what is the airplanes velocity relative to the ground

**Physics**

If a motorboat travels 25km/h towards the sea, down a river whose velocity is 4km/h what is the boats velocity related to the shore?

**Chemistry**

How many copper atoms are in a pure copper statue with a mass of 139kg{\rm kg}

**Chemistry**

Iron ores have different amounts of iron per kilogram of ore. Calculate the mass percent composition of iron for each iron ore: Fe2O3{\rm Fe_2O_3} (hematite), Fe3O4{\rm Fe_3O_4} (magnetite), FeCO3{\rm FeCO_3} (siderite).

**Chemistry**

Citric acid, the compound responsible for the sour taste of lemons, has the following elemental composition: C{\rm C}, 37.51%\%; H{\rm H}, 4.20%\%; O{\rm O}, 58.29%\%.Calculate the empirical formula of citric acid

**statistics**

Suppose a manufacturer claims that each family-size bag of pretzels sold weighs 12 ounces on average with a standard deviation of 0.8 ounces. A consumer's group decides to test this claim. If a simple random sample of 49 bags of pretzels gives a sample mean of 11.8 ounces,...

**chemistryyyy**

(a) What is the pH of a 6.1 ✕ 10-5 M Ca(OH)2 solution? (b) What is the H3O+ concentration of the solution? I already know the answer to part A, I just don't understand how you could use that information to find the concentration of H30+ when its not in the ionic equ...

**chemistryyyy**

Thanks! I got part A but how are you supposed to know the concentration of H30+ if its not in the equation?

**chemistryyyy**

a. What is the pH of a 6.1 ✕ 10-5 M Ca(OH)2 solution? b. What is the H3O+ concentration of the solution? I just cant figure out the ionic equation.

**Physics**

Canadian geese migrate essentially along a north-south direction for well over a thousand kilometers in some cases, traveling at speeds up to about 100 km/h. If one such bird is flying at 100 km/h relative to the air, but there is a 38.0km/h wind blowing from west to east. a) ...

**Physics**

A canoe has a velocity of 0.410m/s southeast relative to the earth. The canoe is on a river that is flowing at 0.510m/s east relative to the earth. Find the magnitude of the velocity v⃗ c/r of the canoe relative to the river

**Algebra 2**

A ball is dropped from 400 ft what is the height of the ball on the 6th bounce? 1 bounce =280 ft 2 bounce= 196 ft 3 bounce = 137.2 How do I figure this out?

**Biology**

what is independent variable definition?

**english **

Please HELP Type the word that the underlined phrase modifies or renames. Store the records OF PAYMENTS in the file cabinet. Question 24.. Type the word that the underlined phrase modifies or renames. The house, AN OLD FASHIONED COTTAGE SURROUNDED BY CREPE MYRTLESs, was charming.

**chemistry**

Acetic acid (CH3CO2H) is a weak acid. As a result, a solution of sodium acetate (NaCH3CO2) will be _____.

**Math**

(1) 8/1 divided (-3 2/5) My answer is 68/1 (2) 3 2/3 divided by -8 6/7 answer 682/21 3) 41/5 x -8/5 =32/25 Please I need help i'm so confused please show work so I can understand these other 27 problems that i have to complete. Thank you Ms. Sue

**Compters**

The major reason for the predominance of the PCI bus in the latest models of PCs is that A. the size and form factor make it easy to package. B. it's exclusively manufactured in the USA. C. the technology was released as open source. D. it uses ASSEMBLER language commands.

**Math**

If x over three minus y over two= negative three. Which statement best explains the value of y changes each time x is increased by one unit? A. The value of y increase by three over two units. B. The value of y increase by two over three units. C. The value of y decrease by th...

**Science**

How is Earth like a system?

**french**

Tu viens d'ou? Comment est CE que le Prof skie? Ou est-CE que tu vas? les crêpe coutent combines? Vous allez a l' Ecole, n'est CE pas?Avec qui est- CE que tu joues au foot? Tu es le professeur match the question question with the letter appropriate answer.tre...

**french**

Match the question with the letter of the appropriate answer pourquoi est - CE que tu e' tudies le francais

**math**

powers and exponents

**math**

can***

**math**

i dont understand, csn you explain it to me

**math**

i dont understand, csn you explain it to me

**math**

i dont understand, csn you explain it to me

**psychology**

In the brain, most excitatory communication in synapses occurs by way of glutamate and most inhibitory communication occurs by way of gamma-aminobutyric acid. In general terms, describe what the other neurotransmitters do.

**calculus**

A cooling tower for a nuclear reactor is to be constructed in the shape of a hyperboloid of one sheet. The diameter at the base is 260 m and the minimum diameter, 500 m above the base, is 200 m. Find an equation for the tower. (Assume the center is at the origin with axis the ...

**calculus**

A cooling tower for a nuclear reactor is to be constructed in the shape of a hyperboloid of one sheet. The diameter at the base is 260 m and the minimum diameter, 500 m above the base, is 200 m. Find an equation for the tower. (Assume the center is at the origin with axis the ...

**algebra **

(3x^2-2x-1) - (5x^2+4x+2)

**algebra**

I think your wrong A=lxW w=x l=2x+1 So it should be something like A=( ) ( ) and that's the part I dont understand

**chemistry**

18.5g Al is submerged in 20.2g of water with a total temperature of 27°C. How much energy in joules is absorbed by the Al if the temperature changes to 32°C ?

**Statistics**

X Y 0 23 2 27 2.3 29 4.1 32 5 35 What is the correlation for this data set? 10) Find the regression line for this data set.

**math**

what is a data

**math**

finding the average

**math**

finding the mean

**Algebra**

Evaluate the determinant of the matrix. [-4 5 6 0 4 4 -2 -5 4]

**Algebra 2 variables**

Find the values of the variables. [-12 -w^2] = [2k -81] [2f 3] [-4 3] Show your work?

**Algebra 2**

Find the sum [1 4] [0 0] [0 3] + [0 0] A - [1 4] [0 3] B - undefined C - [0 0] [0 0] D - [1 0] [4 3]

**math**

evaluate the expressions below and leave them in radical form. 1. sin(pie symbol/6)csc(pie symbol/6) 2. sec(pie symbol/3)cos(pie symbol/3)+tan(pie symbol/3)cot(pie symbol/3)

**science**

thank you.

**science**

plz delete after 20 minutes of answering

**algebra**

A store mixes kenyan coffee worht $12 per kilogram and turkish coffee worth $16 per kilogram the mixture is to sell for $14 per kilogram how much of each should be used to make a 348-kilogram mixture?

**Spanish**

how old am I

**Science**

How do you find the hours of daylight ?

**Algebra 2 **

The Formula s= sqrt 30fd can be estimated the speed of s, in miles per hour that a car is traveling when it goes into a skid, where f is the coefficient of friction and d is the length of the skid marks in feet. Kody skids to a stop on a street with a speed limit of 35 mi/h. h...

**4th grade math**

you find a common denominator, which is 4 in your case, and because you multiply 2 by 2 you have to multiply 41 by 2 as well, so you get 82/4-1/4, ok or do you need more help?

**math**

In the xy-coordinate plane, the distznce between point B(15,7) and point A(x,15) is 17. What is one possible value of x?

**science project**

I'm trying to find information on does lung capacity depend on height

**Reading/Language Arts**

Did i rewrite my paragraph right.Also thank you for your help

**Reading/Language Arts**

the energy we get to heat up the house and run our appliances is a energy solar panel.And it has an adverse affect on it do to the heavy snow fall.The apparatus does not generate enough energy do to lack of sunlight. And we need that energy to power our house for heat hot wat...

**Reading/Language Arts**

The energy we get to heat up our house and run our appliances. Is a solar panel and is a necessity to live an everyday life. Do to a adverse affect on the solar panel caused by to much snow. The apparatus does not get enough sunlight to generate electricity. That the house nee...

**Reading/Language Arts**

I,m writing a paragraph about using resources responsibly.And I have to use three vocabulary words adverse,generate,apparatus. And this is what I wrote. The energy to the house I live in has had a adverse affect.Do to the apparatus not getting enough sunlight to generate all t...

**reading/language arts**

write a paragraph about using resources responsibly using these three words:renewable,nonrenewable,generate.

**greenhouse biology**

what organism is a porkaryotic cell?

**Math**

700 eggs will be needed

**Government**

I don't know.

**Government**

What are the duties of congressional committees?

**Government**

They are in the system of goverment letting each branch keep each other in balance so none of the branches gets too powerful

**Government**

Identify checks and balances.

**Government**

thank you.

**Government**

A progressive tax is a tax whose rate increases as the payers income increases? if individuals who earn high incomes have a greater proportion of their incomes taken to pay the tax? A regressive tax is one whose rate increases as the payers income decreases?

**Government**

Explain progressive and regressive taxes.

**Government**

Explain the social contract theory.

**Government**

Who works on the federal budget?

**Government**

List one of the unalienable rights.

**government**

Describe the different types of primaries.

**government**

How do the duties of the Lieutenant Governor compare to those of the vice president?

**Math**

my answer doesnt show good. I have to fix it.

**Math**

4 5/6 } 5/6 + 3 2/3 } 2 * 2 = 4 ________ - - 7 3 * 2 = 6 Now add 5 + 4 9 - - = - 6 6 6 Now as you see the number has become an improper fraction . So now you do this: A: 9 9 3 7 - = - = 9 - 6 = 3 = 8 - = 6 6 6 1 8 - 2 1 8 - is your answer because when you are 2 changing an im...

**Math**

May you explain how did you get the 20/56 and the 15/56 . I do not know what you did there . Answer back please .

**Math **

Madison spent 5/8 of her savings on a microwave oven and a refridgerator. She used 4/7 of the amount she spent to buy the refrigderator. The refridgerator cost $280 more than the microwave oven. How much savings did Madison start with ?

**Math**

Thank you, Ms. Sue.

**Math **

Jaden wants to cover the floor with square tiles the same size. The floo measures 315 inches by 108 inches. If she uses only whole tiles, find A) the greatest possible length of each tile B) the number of tiles needed to cover the floor.

**Math**

Um... I really didn't understand you very clearly. So can you like go through this so I can understand cause I'm not really fimillar with algerbra.

**Math**

At a festival, 2/7 of the number of girls was equal to 3/5 of the number of the boys. There were 165 fewer boys than girls, how many children were at the festival in all?

**Physics**

Two 0.4 kg soccer balls collide elastically in a head-on collision. The first ball starts at rest, and the second ball has a speed of 3.5 m/s. After the collision, the second ball is at rest. A.) What is the final speed of the ball? B.) What is the kinetic energy of the first ...

**Algebra**

3x2+x+2

**Chem**

What is the volume in liters of 48.0 grams of oxygen gas at 0.0 C and a pressure of 760mm Hg?

**physics**

how much energy would it take to melt 250kg of lead assuming it starts at 30 degrees centigrade.

**MATH!!!!!!!!!!!! I need help please**

Simplify Complex fraction: (x-1) ----- (x-3) --------- 1 4 ---- - ---- x2-x-6 (x+2)

**Algebra!!**

(x-1)/(x-3)/1/x2-x-6-4/(x+2)

**Intermiate Algebra**

Reduce the Rational expression to lowest terms: 3x2-9x+6/10-5x

**Ratio**

Help meeeeee plz.....

**Ratio**

A jar contains 2 red marbles,6 blue marbles,4 white marbles, and 12 black marbles. What is the ratio of white marbles to all marbles?

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