Tuesday
October 21, 2014

Posts by bob


Total # Posts: 2,433

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 ...
February 24, 2012

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
February 24, 2012

Math/Calculus.
Suppose (x^2)*(e^(-2y))= ln(xy) Find dy/dx by implicit differentiation.
February 22, 2012

chemistry
how does the electrolyte paste in a battery work
February 22, 2012

math
I have a rectangle w/ 20 boxes in it what would 1/5 of the boxes be?
February 22, 2012

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
February 21, 2012

English
Tree
February 21, 2012

physics/chemistry
so it is a physics project
February 21, 2012

physics/chemistry
if i'm testing conductivity of different salts?
February 21, 2012

physics/chemistry
is conductivity a physical or chemical property
February 21, 2012

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
February 19, 2012

geometry
In the figure below, the measure of arc AC is 88 degrees if angle ABC is equal to 88 degrees.
February 19, 2012

math
Write as a single log of a single argument: log3 24 + log3 17 - log3 51
February 17, 2012

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?
February 17, 2012

algebra
31
February 16, 2012

chemistry
How many molecules of hydrogen gas are produced by the reaction of tin with 20.0 L hydrogen mono fluoride at STP
February 16, 2012

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 ...
February 15, 2012

Math
What's the answer to "230 is increased to 250?"
February 13, 2012

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...
February 8, 2012

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]/&#...
February 7, 2012

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
February 7, 2012

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.
February 7, 2012

algebra
A box of animal crackers measures 12 inches by 8 inches by 2 inches. What is the volume of the box?
February 7, 2012

algebra
The sum of three consecutive integers is -96. What is the largest integer?
February 7, 2012

algebra
The sum of three consecutive integers is . What is the largest integer?
February 7, 2012

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?
February 7, 2012

math - integers
68 kms
February 7, 2012

Mathg
8*2=16. Answer is 8.
February 6, 2012

math
Side of Square is 25 feet. One side of rectangle is 30 feet and other is 20 feet.
February 6, 2012

math
512
February 6, 2012

math
72
February 6, 2012

math
35*6 is 210 not 200.
February 6, 2012

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 ?
February 6, 2012

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 ...
February 6, 2012

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 ?
February 6, 2012

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 ?
February 6, 2012

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 ...
February 6, 2012

geometry
ABCD is a trapezoid with DC parallel to AB, AB=4, AD=4, angle A=60, angle C=45. Find DC and BC
February 3, 2012

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?
February 3, 2012

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?
February 3, 2012

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 ...
February 1, 2012

physics
122
February 1, 2012

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...
January 30, 2012

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.
January 30, 2012

Chemistry
How many grams of CO2 are formed when 32 g of O2 reacts with 23 g of C2H5OH?
January 29, 2012

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?
January 29, 2012

Chemistry
Using VSEPR what is the shape of ammonia (NH3) and water (H2O) when bonded to a hydrogen bond?
January 28, 2012

Chemistry
Using VSEPR what is the shape of ammonia (NH3) and water (H2O)?
January 26, 2012

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,...
January 25, 2012

Chemistry
1000
January 23, 2012

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
January 22, 2012

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.
January 21, 2012

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 ...
January 20, 2012

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?
January 20, 2012

math
what is the sum of the odd numbers 1-2009
January 18, 2012

pre cal
Given triangle ABC, A = 120, a = 8, b = 3; determine B to the nearest whole degree
January 18, 2012

physics
Hey there, Did anyone give you an answer? I'm just wondering because I too have a similar question.
January 17, 2012

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?
January 16, 2012

finance
12.2%
January 11, 2012

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 ...
January 11, 2012

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...
January 11, 2012

math
4square root.Of 5
January 10, 2012

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
January 8, 2012

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?
January 6, 2012

Physics
65
December 20, 2011

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?
December 20, 2011

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 ...
December 15, 2011

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, ...
December 15, 2011

chem
How many grams are in 3.6 moles of agcl2?
December 15, 2011

math
what is equivalent to 98% o.49 or 100/98 or o.98 or 49/100
December 15, 2011

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?
December 14, 2011

math 6th grade
How to write out 10 the negative 6?
December 14, 2011

math 6th grade
How to write out 10 to the negetive two?
December 14, 2011

math 6th grade
(1/2) to the 5th power= Need to know how to write this?
December 14, 2011

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?
December 12, 2011

Math Grade 3
You move the decimal to the left for example: 123 divide by 10 is 12.3
December 12, 2011

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 ...
December 11, 2011

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?
December 11, 2011

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?
December 11, 2011

chemistry
by moles
December 11, 2011

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?
December 11, 2011

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.
December 11, 2011

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
December 10, 2011

chemistry
the ratio is moles
December 10, 2011

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?
December 10, 2011

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?
December 8, 2011

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 ...
December 8, 2011

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?
December 8, 2011

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
December 8, 2011

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????
December 8, 2011

science
Is melting ice a physical or chemical change? I think it is a physical change. Am I correct?
December 8, 2011

geometry
do ur own homework
December 8, 2011

la poetry
i need help with narrative soccer
December 7, 2011

physics
An 77 person stands on a uniform ladder 4.0 long, that weighs 100 , as shown in the figure . The floor is rough; hence, it exerts both a normal force, , and a frictional force, , on the ladder. The wall, on the other hand, is frictionless; it exerts only a normal force, . the ...
December 7, 2011

Physics
A 86.0 kg diver falls from rest into a swimming pool from a height of 6.3 m. It takes 1.44 s for the diver to stop after entering the water. Find the magnitude of the average net force exerted on the diver during that time.
December 6, 2011

physics
Gas is confined in a tank at a pressure of 10 atm and a temperature of 14◦C. If 58 percent of the gas is withdrawn and the temperature is raised to 50◦C, what is the new pressure in the tank?
December 5, 2011

chemistry
4.89 atmospheres
December 5, 2011

Math
Rewrite cos(arcsin(v)) as an algebraic expression in v. i know that the answer is squroot of 1-v^2 but i dont know the process of how to come to this answer. Thanks for the help!
December 4, 2011

10th grade World History
fdsgdfgdfgsdf
December 3, 2011

physics
A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. (a) At what distance from the center of the Earth is the force due to the Earth three times the magnitude of the force due to the Moon?
December 2, 2011

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