Wednesday
April 16, 2014

Posts by Bob


Total # Posts: 2,358

chemistry
A particular reaction has an activation energy of 51.6 kJ/mol-rxn. How much faster is the reaction at 50 degrees C versus 25 degrees C? a. 2 times b. 5 times c. 3 times d. half as fast d. 20% as fast help No one has answered this question yet.

chemistry
For a one step reaction, the activation energy for the forward reaction is 40.0 kJ/mol and the enthalpy of reaction is -20.0 kJ /mol. Which statement below is true? a. The activation energy of the forward reaction would be affected to a greater extent than the activation energ...

chemistry
If the reaction Cl2 (g) + O3 (g) = Cl2O (g) + O2 (g) occurred in just two steps, what would be the overall order of the reaction be? a. 1 b. 2 c. 3 d. 4 e. not possible to determine from the information given

chemistry
A catalyst alters the rate of a reaction by a. changing the products in the reaction. b. increasing the activation for the reaction. c. always providing a surface on which the molecules react. d. providing an alternate pathway for the reaction. e. increasing the concentrations...

chemistry
The equation A + 2 B = C + D describes an elementary reaction, which takes place in a single step. Thus, the rate law must be a. rate = k(A]2 b. rate = k(B]2 c. rate = k(A][B] d. rate = k(A][B]2 e. none of the above represents the rate law for this elementary reaction.

chemistry
The decomposition of hydrogen peroxide in solution and in the presence of iodide ion was studied in laboratory, and the following mechanism proposed based on the experimental data. H2O2 + I - = H2O + IO - (slow) H2O2 + IO - = H2O + O2 + I - (fast) Which one of the following st...

chemistry
The reaction: A + 3 B = D + F was studied and the following mechanism was finally determined A + B = C (fast) C + B = D + E (slow) E + B = F (very fast) The step with largest activation energy is a. the first step b. the second step c. the third step d. none of the steps has a...

chemistry
For a particular chemical reaction, the rate constant at 30.0 °C is 1.38 X 10-4 L mol-1 s-1, while the value at 49.0 °C is 1.21 X 10-3 L mol-1 s-1 . What is the activation energy for this reaction? a. 92.8 kJ b. 200 kJ c. 40.4 kJ d. 343 kJ e. 56.4 kJ ln 1.38x 10 -4 / 1...

chemistry
For a certain chemical reaction, the rate constant at 250.0 °C is 0.00383 s-1 and the activation energy is 22.40 kilojoules. Calculate the value of the rate constant at 335.0 °C. a. 0.00513 s-1 b. 0.00946 s-1 c. 0.00787 s-1 d. 0.0224 s-1 e. 0.000640 s-1 b or c

chemistry
For a one step reaction, the activation energy for the forward reaction is 40.0 kJ/mol and the enthalpy of reaction is -20.0 kJ /mol. Which statement below is true? a. The activation energy of the forward reaction would be affected to a greater extent than the activation energ...

chemistry
A particular reaction has an activation energy of 51.6 kJ/mol-rxn. How much faster is the reaction at 50 degrees C versus 25 degrees C? a. 2 times b. 5 times c. 3 times d. half as fast d. 20% as fast help

Math/Calculus.
Suppose (x^2)*(e^(-2y))= ln(xy) Find dy/dx by implicit differentiation.

chemistry
how does the electrolyte paste in a battery work

math
I have a rectangle w/ 20 boxes in it what would 1/5 of the boxes be?

Science
B: water is constintly evaporating over the ocean's surface.

Science
B: water is constintly evaporating over the ocean's surface.

calculus
The voltage signal from a standard European wall socket can be described by the equation V(t)=325sin100 pi x , where t is time, in seconds and V is the voltage at time, t. determine the period frequency and amplitude

English
Tree

physics/chemistry
so it is a physics project

physics/chemistry
if i'm testing conductivity of different salts?

physics/chemistry
is conductivity a physical or chemical property

math
a data set of size 19 has correlation coefficient of r= 0.432. Test the significance of r at the 5% level and at the 1% level

geometry
In the figure below, the measure of arc AC is 88 degrees if angle ABC is equal to 88 degrees.

math
Write as a single log of a single argument: log3 24 + log3 17 - log3 51

Math
For a class play, student tickets cost $2 and adult tickets cost $5. A total os 30 tickets were sold. If the total sales must exceed $90, what is the miniuim number of adult tickets that must be sold?

chemistry
How many molecules of hydrogen gas are produced by the reaction of tin with 20.0 L hydrogen mono fluoride at STP

PHYICS HELP
While a person is walking, his arms swing through approximately a 45° angle in .530s. As a reasonable approximation, we can assume that the arm moves with constant speed during each swing. A typical arm is 70.0 cm long, measured from the shoulder joint. 1) What is the acce...

Math
What's the answer to "230 is increased to 250?"

Physics
Henrietta is going off to her physics class, jogging down the sidewalk at a speed of 2.05 m/s. Her husband Bruce suddenly realizes that she left in such a hurry that she forgot her lunch of bagels, so he runs to the window of their apartment, which is a height 43.9 m above the...

chemistry
Consider the reaction below: Cgraphite(s) + F2(g) +1/2O2(g) → CF2O(g) Which of the following is a correct rate expression? 1. rate = −2∆[O2]/∆t 2. rate = −∆[CF2O]/∆t 3. rate =∆[F2]/∆t 4. rate = −∆[Cgraphite]/...

Chemistry
Carbon dioxide gas has a solubility of 0.0972 g/100 g H2O at 40 degrees celsius. Expressed in parts per million, this concentration is closest to... (1)0.972 ppm (2)9.72 ppm (3)97.2 ppm (4)972 ppm

geometry
A regular hexagon has side lengths 15 in. The perimeter of the hexagon is 90 in. A second hexagon has side lengths 18.75 in. Find the perimeter of the second hexagon. Round to the nearest tenth.

algebra
A box of animal crackers measures 12 inches by 8 inches by 2 inches. What is the volume of the box?

algebra
The sum of three consecutive integers is -96. What is the largest integer?

algebra
The sum of three consecutive integers is . What is the largest integer?

algebra
Ky has 3 times more books than Grant, and Grant has 6 fewer books than Jaime. If the total combined number of books is 176, how many books does Jaime have?

math - integers
68 kms

Mathg
8*2=16. Answer is 8.

math
Side of Square is 25 feet. One side of rectangle is 30 feet and other is 20 feet.

math
512

math
72

math
35*6 is 210 not 200.

physics
in 1989 michel menin of france walked on a tightrope suspended under a balloon nearly at an altitude of 3150 m above the ground . suppose a coin falls from menin's pocket during his walk . how high above the ground is the coin when its speed is 60 m/s ?

physics
the largest watermelon ever grown had a mass of 118 kg. suppose this watermelon were exhibited on a platform 5 m above the ground . after the exhibition, the watermelon is allowed to slide along to the ground along a smooth ramp, How high above the ground is the watermelon at ...

physics
A Physics book , mass unknown , is dropped from a table . its velocity just before hitting the ground is 9.39 m/s . what is the height of the table ?

physics
a 20 kg rock is on the edge of a 100 m cliff . the rock falls from the cliff , what is its kinetic energy just before it hits the ground ?

materials science
A bar of pure nickel is coupled with a bar of pure iron (interfaced). The diffusion couple is then heated to a temperature of 1000°C. (a) How long will it take for the concentration of nickel to reach 0.1 wt%, 1.0 μm below the interface? (b) How long will it take for ...

geometry
ABCD is a trapezoid with DC parallel to AB, AB=4, AD=4, angle A=60, angle C=45. Find DC and BC

chemistry
In a nickel bath with a total volume of 1000 gallons, titration of a 50 milliliter sample with 0.1 N silver nitrate used up 10.5 milliliters to the end point. What is the concentration in ounces per gallon of the nickel chloride (NiCl2 ) in the bath?

chemistry
A 10 milliliter sample of HCl pickle is titrated with 0.2 N NaOH to a phenol-phthalein end point and it is found that 6.5 milliliters are used. What is the concentration of HCl in the Pickle in grams per liter? In weight Percent?

math
Bob and Jack play a shooting game. In this game, they have a net at a distance. The net is made up of 1 mm thick wires. The wires run vertically and horizontally to form a mesh that has 5 mm square openings between them. A bullet 2 mm in diameter must be shot in such a way tha...

calculus
actually an ODE question(but there's no diff. eq. subforum) (y^2)(dy/dx)+y^3/x =2/x^2 using substitution u(x)=y^3 so I've been doing a few of these and getting them all wrong and this problem... I don't know where to start. I tried (1/u)(du/dx)+u/x(du/dx)=2/x^2 but...

materials science
Consider a copper lattice with an excessive average of one vacancy in every 100 unit cells. What will be its density? Compare this to the theoretical density of copper.

Chemistry
How many grams of CO2 are formed when 32 g of O2 reacts with 23 g of C2H5OH?

algebra
parking lot had a length that is 7 yards greater than thre width. the area of the lot is 450 square yards. what is the length and width?

Chemistry
Using VSEPR what is the shape of ammonia (NH3) and water (H2O) when bonded to a hydrogen bond?

Chemistry
Using VSEPR what is the shape of ammonia (NH3) and water (H2O)?

Math
Rebecca gives gifts to 12 employees. Each gift is in a box that is 12 inches by 10 inches by 3 inches. How much wrapping paper does Rebecca need to completely the cover the boxes? F. 360 in(insert exponent 2) G. 1,720 in(insert exponent 2) H. 4,320 in(insert exponent 2) J. 14,...

Chemistry
1000

Chemistry Lab
we reacted acetic acid with butanol and formed butyl acetate which is supposed to smell like banana but it smelled like sharpie/nail polish remover why might this be

chemistry
An insulated beaker contains 250.0 grams of water at 25C. Exactly 41.6 g of a metal at 100.0C was dropped in the beaker. The final temperature of the water was 26.4C. Assuming that no heat is lost in any other way, calculate the specific heat of the metal.

Physics
A wooden block of mass 29.0 kg sits on a horizontal table. A wire of negligible mass is attached to the right side of the block and goes over a pulley (also of negligible mass, and frictionless), where it is allowed to dangle vertically. When a mass of 15.5 kg is attached to t...

physics
An astronaut in his space suit has a total mass of 275 kg. His weight on the asteroid Erewhon is 0.3 N. What is the acceleration of gravity on Erewhon?

math
what is the sum of the odd numbers 1-2009

pre cal
Given triangle ABC, A = 120, a = 8, b = 3; determine B to the nearest whole degree

physics
Hey there, Did anyone give you an answer? I'm just wondering because I too have a similar question.

physics
Friction provides the force needed for a car to travel around a flat, circular race track. What is the maximum speed at which a car can safely travel if the radius of the track is 82.0 m and the coefficient of friction is 0.39?

finance
12.2%

chemisty
The molar heat capacity of C6H6(ℓ) is 136 J/mol ·◦C and of C6H6(g) is 81.6 J/mol · ◦C. The molar heat of fusion for benzene is 9.92 kJ/mol and its molar heat of vaporization is 30.8 kJ/mol. The melting point of benzene is 5.5 ◦C, its boili...

chemistry
When 0.373 g of compound X is burned completely in a bomb calorimeter containing 3000 g of water, a temperature rise of 0.341 C is observed. What is ∆Urxn for the combustion of compound X? The hardware component of the calorimeter has a heat capacity of 3.19 kJ/ ◦C...

math
4square root.Of 5

PARALLELOGRAM WRITING A PROOF
given 1.vx is con to xt by csctc ux con xs 2. x is midpoint of those 2 lines 3.vuts is a paarlelogram

physics
A 640-kg racing car completes one lap in 14.3 s around a circular track with a radius of 45.0 m. The car moves at constant speed. (a) What is the acceleration of the car? m/s2 (b) What force must the track exert on the tires to produce this acceleration?

Physics
65

Physics
A 18 kg object and a 26 kg object are connected by a massless compressed spring and rest on a frictionless table. After the spring is released, the object with the smaller mass has a velocity of 2 m/s to the left. What is the velocity of the object with the larger mass?

Math
Five employees at the Wild Fowl Publishing Company each come to work by a different one of five means: car, railroad, subway, and walking. They hold these positions at the company: art director, editor, publisher, receptionist, and secretary. Two of them are men named Finch an...

math
A popular new secretary at the law firm of Farnsworth, Newman, O’Malley, Price, and Reynolds, is taken to lunch by a different one of those five men on each of her first week on the job. Each man took her to eat at a different one of these five types of food: Chinese, Fre...

chem
How many grams are in 3.6 moles of agcl2?

math
what is equivalent to 98% o.49 or 100/98 or o.98 or 49/100

6 th grade Math
You can find the total number of different 4-digit numbers of choices for each digit (9) to the number of digits (4), or 9 to the 4th power. Based on this pattern, how many different 5-digit numbers could you make from the digits 1 through 8?

math 6th grade
How to write out 10 the negative 6?

math 6th grade
How to write out 10 to the negetive two?

math 6th grade
(1/2) to the 5th power= Need to know how to write this?

chemistry
Atom X has atomic mass (A) = 40 and atomic number (Z) = 20. Atom Y has A = 42 and Z = 20. How are these two atoms related?

Math Grade 3
You move the decimal to the left for example: 123 divide by 10 is 12.3

chemistry
. Compound C (MW = 550) is provided at a concentration of 25g/100mL. 1mL is taken and compound D is to be added (MW = 1025, concentration = 75mM) to give a final ratio of compound C:D of 4:1 moles ratio. What volume of compound D is to be added? ***Dr BOB222 THE 4:1 RATIO IS B...

chemistry
6. Compound C (MW = 550) is provided at a concentration of 25g/100mL. 1mL is taken and compound D is to be added (MW = 1025, concentration = 75mM) to give a final ratio of compound C:D of 4:1 moles ratio. What volume of compound D is to be added?

chemistry
6. Compound C (MW = 550) is provided at a concentration of 25g/100mL. 1mL is taken and compound D is to be added (MW = 1025, concentration = 75mM) to give a final ratio of compound C:D of 4:1 moles ratio. What volume of compound D is to be added?

chemistry
by moles

chemistry
6. Compound C (MW = 550) is provided at a concentration of 25g/100mL. 1mL is taken and compound D is to be added (MW = 1025, concentration = 75mM) to give a final ratio of compound C:D of 4:1 moles ratio. What volume of compound D is to be added?

can you please look over my answers? clauses
Select the abbreviation that tells how the italicized noun clause is used. S-subject, DO-direct object, SC-subject complement, OP-object of preposition A lecture on cleanliness was not what the children wanted to hear.

trig
The manufacturer of a propeller for a small aircraft mandates a maximum operating angular velocity of 300 rad/s. Determine whether it is safe to install this propeller whose aircraft whose engine is expected to run at a maximum of 2800 rpm

chemistry
the ratio is moles

chemistry
Compound C (MW = 550) is provided at a concentration of 25g/100mL. 1mL is taken and compound D is to be added (MW = 1025, concentration = 75mM) to give a final ratio of compound C:D of 4:1. What volume of compound D is to be added?

help!!!!
A navy destroyer is exactly 68 miles North of an aircraft carrier, which is travelling West 21 degrees North at 18 mph. what speed and bearing must the destroyer maintain if it is to reach the aircraft carrier in exactly 3 hrs? is it 226mph?

pre calc
each of three circles touches the other 2.circle A has a radius of 8 cm. circle B has a radius of 4 cm.circle C has a radius of 1 cm.a triangle is formed by connecting the centers of the 3 triangles. determine the largest angle for the triangle and in which circle is the large...

pre calc
you are 7 miles north and 4 miles west of a cabin.how far are you from the cabin? on what bearing must you walk to reach the cabin?

math
find all solutions on 0 is greater than or equal to theta < 2pi cos theta= 2sqrt3/3 4-1/2sin theta= (-16+sqrt3)/4 3(sqrt3)= -3cot theta -2=-1-2sin theta

math
the hour hand of a clock is 5 inches long and the minute hand is 6 inches long. determine the distance between the tips of the hands at 11:40 pm????

science
Is melting ice a physical or chemical change? I think it is a physical change. Am I correct?

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