# Posts by bob

Total # Posts: 3,229

**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*

**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*

**algebra**

In 16 years, Ben will be 3 times as old as he is right now. How old is he right now?

*February 15, 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*

**Rydberg equation**

42

*February 13, 2012*

**Math**

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

*February 13, 2012*

**math**

8/year

*February 12, 2012*

**Math**

25 times 4 is the man with purple eyes

*February 12, 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**

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*

**physics**

gtfo fag^

*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*

**chemistry**

6.8 grams

*February 4, 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*

**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*

**math**

help me pls

*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**

As above, as the x-value for particle 3 approaches infinity the only force acting on particle 2 is from particle 1. The asymptote is the value of that force. Set the equation for (kq1q2)/(r^2) = 1.370e-25N and solve for q2. Note that you can solve for r with the knowledge that...

*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*

**Chemistry**

1620 J

*January 15, 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**

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*

**math**

163.8

*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*

**science**

10.8kg

*December 9, 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*