Friday

April 18, 2014

April 18, 2014

Total # Posts: 1,682

**Chemistry**

Ag2S is an insoluable black solid. Would more solid dissolve, or precipitate once the following are added to the solution. 1. KS-----I know [S] increases, shift to reactants side, precipitate 2. HClO 3. LiOH 4. NH4OH

**math**

Twenty people apply for seven jobs that are available at fly by night aircraft company 12 are men and the rest are women. How many seven person groups have exactly three men? How many of these seven person groups have exactly three men or three women?

**math**

Twenty people apply for seven jobs that are available at fly by night aircraft company In how many ways could such a group be composed? After the seven have been selected, in how many different ways could five of them be assigned to the assembly department?

**Sci.**

The boundary between 2 plates moving together is calle _______.

**trig**

write sin4xcos2 as the sum or difference of two functions. answers: 1/2(cos6x+cos2x), 1/2(cos2x-cos6x), 1/2(sin6x+sin2x), sin6x-sin2x

**trig**

find the angle between vector U=<2,3> and V=<1,-5> answers: 88 degrees, 45 degrees, 135 degrees, or 92 degrees...?

**Chemistry**

A solution of formic acid 0.20 M has a pH of 5.0. What is its Ka value? a) 5.0 x 10-10 b) 1.0 x 10-5 c) 5.0 x 10-5 d) 25

**Chemistry**

Mols benzoic acid = 12.2g/122.12g = 0.0999 Int. Concentration of Benzoic acid = 0.0999 mol/ 0.500L = 0.1998 M Ka = 6.3 x 10-5 = (x)(x)/0.1998 – x X = [H+] = * M pH = -log(*) = * Sorry, this question is just really confusing me..

**Chemistry**

Thanks so much, you're an awesome help.

**Chemistry**

Mols benzoic acid = 12.2g/122.12g = 0.0999 Int. Concentration of Benzoic acid = 0.0999 mol/ 0.500L = 0.1998 M Ka = 6.3 x 10-5 = (x)(x)/0.1998 – x X = [H+] = * M pH = -log(*) = * Sorry, this question is just really confusing me..

**Chemistry**

Calculate the pH of a solution prepared by dissolving 12.2 g of benzoic acid in enough water to produce a 500 mL solution. Ka = 6.3 x 10^-5

**Chemistry**

Can a solution of CrCl3 be stored in an aluminum container?

**Chemistry**

Using the following spontaneous reactions, classify the 3 metals involved (Cr, Sn, Al) according to increasing reductant properties. a) 2Cr + 3Sn2+ 2Cr3+ + 3Sn b) Al + Cr3+ Al3+ + Cr

**Chemistry**

Which pair of ions will be most likely to react at standard state conditions? 1. a) MnO4- and Sn2+ 2. b) Zn2+ and Cl- 3. c) I- and Cu 4. d) Fe3+ and Cu2+

**Chemistry**

If a piece of copper metal is dipped into a solution containing Cr3+ ions, what will happen? Explain with Ev values

**Chemistry**

Pb(NO3)2(aq) 2 x 10-3 M Na2SO4(aq) 2 x 10-3 M Pb(NO3)2(aq) + NaSO4(aq) → PbSO4(s)+ 2NaNO3(aq) a) What are the concentrations of each ion within this solution? b) If 1L of each solution is mixed; will a precipitate form? why?

**Spanish-8th grade Help!**

Thank you- I think what I put is right- I've rechecked it but it seems so odd the way I have it.I know it's a reflexive so maybe it is correct.

**Soanish-8th grade Help!**

I'm trying to conjugate this in the past tense tú/presentarse would I conjugate it in past tense like this- (tú te presentaste) Something looks wrong with it

**math**

what is the first step in solving the equation x/5 - 9=6?

**Physics Help**

So is there no shift? and if so why is that the case?

**Physics Help**

If we witness events taking place on the moon, where gravitation is weaker than on Earth, would we expect to see a gravitational red shift or a gravitational blue shift? and Explain please a)blue shift b)red shift c)no shift

**Chemistry**

The following reaction has a Delta G value of 42.6 kJ/mol at 25oC: HB(aq) +H2O(l) --> H3O+(aq) +B-(aq) Calculate Ka for the acid HB.

**Physics Help!!**

Comparing Einstein's and Newton's theories of gravitation, can the correspondence principle be applied? and Why or Why not? a)Yes b)No

**Physics Help please**

If we witness events taking place on the moon, where gravitation is weaker than on Earth, would we expect to see a gravitational red shift or a gravitational blue shift? and Explain please a)blue shift b)red shift c)no shift

**Chemisttry**

A 100.0-mL sample of 0.250 M aniline (C6H5NH2) is titrated with 0.500 M HCl. What is the pH at the equivalence point?

**Chemistry**

You take 326 g of a solid (melting point = 57.6oC, enthalpy of fusion = 346 J/g) and let it melt in 757 g of water, and the water temperature decreases from its initial temperature to 57.6oC. Calculate the initial temperature of the water. (Note that the speciﬁc heat ca...

**Physics Help!!**

A passenger on an interplanetary express bus traveling at v = 0.94c takes a seven-minute catnap by his watch. How long does the nap last from your vantage point on a fixed planet?

**Physics Help please**

A bus moving with speed 0.93c is 65 feet long according to its passengers and driver. What is its length from your vantage point on a fixed planet?

**Chemistry**

Thanks it worked perfectly

**Chemistry**

there isnt a kp or a kc

**Chemistry**

Nitrogen gas (N2) reacts with hydrogen gas (H2) to form ammonia (NH3). At 200 oC in a closed container, 1.1 atm of nitrogen gas is mixed with 2.1 atm of hydrogen gas in an otherwise empty container. At equilibrium, the total pressure is 2.2 atm. Calculate the partial pressure ...

**Physics!!**

Green light is emitted when electrons in a substance make a particular energy-level transition. If blue light were instead emitted from the same substance, would it correspond to a greater or lesser change of energy in the atom? and why?

**chemistry**

Gaseous butane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 16.9 g of butane is mixed with 39. g of oxygen. Calculate the minimum mass of butane that could be left over by the chemical reaction. Round your answer to 2 significant...

**chemistry**

Gaseous butane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 16.9 g of butane is mixed with 39. g of oxygen. Calculate the minimum mass of butane that could be left over by the chemical reaction. Round your answer to 2 significant...

**math**

if you invest 500 dollars in a savings account that pays 8% interest per year, compounded quarterly, how much will you have in the account at the end of 11.6 years?

**statistics**

What type of statistical information would I include in my report to determine our year-to-date performance of our division; example, mean, median, or standard deviation.

**Life orientation**

It damages communities

**Math**

In an election, ethan got 5 fewer votes than christohper,who got 3 more votes than olivia, who got 4 fewer votes than Ava. How many more votes did ava get than ethan ?

**math**

Given P(x) = x^3 - 3x^2 - 5x + 10 a evaluate P9x) for each integer value of x from -3 through 5 b. Prove that 5 is an upper bound on the zeros of P(x)

**Physics**

Two masses, m1=3kg and m2=2kg, are suspended with a massless rope over a pulley of mass M = 10kg. The pulley turns without friction and may be modeled as a uniform disk of radius R=.1m. You may neglect the size of the masses. The rope does not slip on the pulley. The system be...

**Calculus**

Suppose vectors a and b are vectors such that a x b =(3,1,4). What is the cross product of twice of a with twice of b?

**Calculus/Physics Please help!!**

An intravenous line provides a continuous flow of drug directly into the blood. Assuming no initial drug in the blood, the amount of drug in the blood t hours after the dosing begins in m(t) - (a/k)(1-e^-kt), for t (=>)0, where k is the rate constant (again related to half ...

**CALCULUS PLEASE HELP!!**

suppose m(0) milligrams of a drug are put in the blood of an injection. The amount of drug t hours after the injection is given by m(t)=m(o)e^-kt, for t (=>) 0, where k is the rate constant, which is related to the half life. we also treat oral administration of drugs as an...

**Calculus**

Could someone please explain on how to do this question step-by-step. Thank you! A bolt is being loosened by a 40 cm wrench. The torque in this situation has a magnitude of 12 J and the force makes an angle of 60 degree with the wrench. What is the magnitude of the force used ...

**CALCULUS PLEASE HELP!!**

suppose m(0) milligrams of a drug are put in the blood of an injection. The amount of drug t hours after the injection is given by m(t)=m(o)e^-kt, for t (=>) 0, where k is the rate constant, which is related to the half life. we also treat oral administration of drugs as an...

**Calculas**

suppose m(0) milligrams of a drug are put in the blood of an injection. The amount of drug t hours after the injection is given by m(t)=m(o)e^-kt, for t (=>) 0, where k is the rate constant, which is related to the half life. we also treat oral administration of drugs as an...

**Calculus**

I checked in the book answer and the site u gave me matched with the answer. How did the website get solutions as: x= -3.28183 x= -1.863

**Calculus**

Use the algorithm for curve sketching to sketch the graph of each function. a) f(x) 4x^3+6x^2-24x-2 1. First to find intercepts y=0 0=4x^3+6x^2-24x-2 =2(2x^3+3x^3-12x-1) I don't know how to find the x-intercept. I can't use quadratic formula or synthetic division :S

**Math help**

So do I draw lines through the vertices?

**Math help**

Sketch the graph: (x+2)^2/25-(y+4)^2/25=1 I don't understand this at all! When I tried graphing it I just had two lines going through the center, which is (-2,-4). But it should be a hyperbola, right? Could anyone help me?

**World History**

During the Columbian Exchange what diseases were brought from the new world to Europe?

**HELP PLEASE PHYSICS!!**

Thank you!!!

**HELP PLEASE PHYSICS!! **

How much does it cost to operate a 100 W lamp continuously for 1 week if the power utility rate is 8/kWh? answer in $

**Physics Need Help PLEASE**

okay great!!! Thank you again!!!! you do a wonderful job!!!!

**Physics Need Help PLEASE**

its looking for the N/C I got 4*10^-21 but I'm not getting it correct

**Physics Need Help PLEASE**

Thank you so much Elena that helped me out a lot! I was wondering if you could also help me with another question. A droplet of ink in an industrial ink-jet printer carries a charge of 6 10-13 C and is deflected onto paper by a force of 2.4 10-7 N. Find the strength of the ele...

**Physics Need Help PLEASE**

Two point charges are separated by 8 cm. The attractive force between them is 14 N. If the two charges attracting each other have equal magnitude, what is the magnitude of each charge?

**Calculus**

Which plane goes through the origin and is perpendicular to the line r=(2,-2,1) + s(2,3,-4), seR? a) 2x-2y+z=0 b) 2x+3y-4z=0 c) 2x+3y+z-4=0 d) none of the above. I got D, none of the above. I have substituted and couldn't find the answer equal to zero.

**Calculus**

Are the points P(1,2), Q(7,3) and R(-2,1) o the line with vector equation r=(19,5) +s(6,1), SeR

**Calculus**

which pair of lines are perpendicular? a) 2x + 3y - 7=0, -3x - 2y + 2=0 b) 2x - 3y + 2=0, 5x - 7y + 2=0 c) -4x + y - 3=0, x + 4y=0 d) -5x + y + 1=0, 5x + y + 1=0 Please explain. I know we have to use the dot product :3

**engineering mechanics**

14 degrees

**engineering mechanics**

14 degrees

**Calculus**

A rusted bolt requires 30 J of torque to be loosened. If only 40 N of force is applied to a wrench with which it makes a 90° angle, how long is wrench?

**Calculus**

Determine the value(s) of k such that the area of the parallelogram formed by vectors a = (k+1, 1,-2) and b =(k,3,0) is [sqrt(41)]

**Calculus**

For which value(s) of k will the dot product of the vectors (k,2k-1, 3) and (k,5,-4) be 7? I did this so far, 2k-1=5 6/2 k=3

**College Chemistry**

Write three equations (including ΔH values) that represent the heats of formation for each C6H12O6(s), CO2(g), and H2O(l). (Hint: look up heats of formation for each participant)

**Calculus**

Two force vectors act on an object and the dot product of the two vectors is 20. If both of the force vectors are doubled in magnitude, what is their new dot product?

**Calculus**

Sorry for the confusion. May I ask why my answer does not work? :S its asking for the vertices, not equal to Point P.

**Calculus**

Why add?

**Calculus**

I am bit of confused from this question. I have shown the work below and to subtract, am I supposed to be X2 - X1, Y2-Y1, Z2-Z1? or X1-X2, Y1-Y2, Z1-Z2? ------------------------------------ A triangle has sides formed by the vectors PA=(2,7,3) and PB=(6,2,2). The point P=(1,3,...

**Physics**

A box of mass m=1.5 kg is attached to a spring with force constant k=12 and suspended on a frictionless incline that makes a 30 degree angle with respect to the horizontal. With the spring in its unstretched length, the box is released from rest at x=0. The box slides down the...

**Calculus**

I am bit of confused from this question. I have shown the work below and to subtract, am I supposed to be X2 - X1, Y2-Y1, Z2-Z1? or X1-X2, Y1-Y2, Z1-Z2? ------------------------------------ A triangle has sides formed by the vectors PA=(2,7,3) and PB=(6,2,2). The point P=(1,3,...

**Calculus**

1. Which of the following sets of vectors spans [r^2] ? a) {(1,1), (-2,-2)} b) {(1,1), (1,2)} c) {(1,2), (1/2,2)} d) {(-1,1), (1,-1)} 2. Which of the following sets of vectors spans [r^3] ? a) {(1,1,1), (2,2,2)} b) {(1,3,1), (2,2,2)} c) {(1,2,1), (1/2,1,1/2)} d) {(1,3,2), (-1,...

**Calculus**

Point A=(1,3,4) and point B=(-2,2,0). Determine AB. a) (3,1,4) b) (-3,-1,-4) c) (-1,5,4) d) (1,5,4) I chose answer C. 2. A goes from (2,1) to (4,-1) Determine the components of A. a) (6,0) b) (-2,2) c) (2,-2) d) (0,6)

**Calculus**

Vector D represents: URL is here imgur dot com/AX4EN a) A+B b) A-B c) C+B d) A+C I chose answer A. Is that the correct answer?

**Chemistry**

How many moles of nitrogen are needed to produce 1.52 moles of nitrogen (ll) oxide ? N2 + O2 > FeCL3 + 3H20

**Algebra**

Use the substitution method to solve -x + 3y=24 5x +8y=-5

**Calculus and vectors**

|C|=5 and |D|=8. The angle formed by vectors C and D is 35 degrees, and the angle formed by vectors A and C is 40 degrees. Determine |B|. Could someone explain this question

**fractions**

6/8 pizza left, which can be reduced to 3/4.

**Calculus and vectors-Help~David**

Thank you very much!

**Calculus and vectors-Help~David**

Rectangular prism is defined by vectors (2,0,0)(0,9,5) and (0,0,3). Find the volume. I have done this so far, would anyone please verify this. (2,0,0)(0,9,6) (0-2, 9-0, 6-0) =(-2,9,6) (-2,9,6)(0,0,3) =(2,-9,-3) (2)(-9)(-3)=54 cm^3 Therefore volume is 54 cm^3

**Calculus**

Is B=(2,-1,-6)?

**Calculus **

If A=(1,2,4) and Vector A+B =(3,1,-2). What is B?

**Calculus and vectors @ Bob Purs**

I multipled by 2 since its a rectangle, there is an example of similiar to this question but its a triangle.

**Calculus and vectors @ Bob Purs**

Rectangle side is represented by (2,3) and (-6,4). Find the perimeter of rectangle. Is this correct? (-6-2), 4-3) sqrt(8^2+1^2) sqrt(65) =8.062257748(2) =16.124?

**Math**

Is this correct? ((-6-2), 4-3) sqrt(8^2+1^2) sqrt(65) =8.062257748(2) =16.124?

**Math**

Rectangle side is represented by (2,3) and (-6,4). Find the perimeter of rectangle. Do I have to find the magnitude of (2,3) and (-6,4) and square root the answer?

**Calculus**

Thank you for answering. Don't I have to find the magnitude then use square root of the answer and multiply by 2? If so, could you show it.

**Calculus **

Rectangle side is represented by (2,3) and (-6,4). Find the perimeter of rectangle. Could someone please help~

**Calculus and vectors**

Could someone explain to me how I can find the area/perimeter/volume of a rectangular prism if I am given R^3 points. For example find area of rectangular prism given pts (2,3,4)(5,3,2), similar to this.

**Calculus and vectors**

Bob can swim at a rate of 5km/h. He is in a river that is flowing at a rate of 9 km/h. a) if bob swims upstream, what is his relative velocity to the ground? b)if bob swims downstream, what is his relative velocity to the ground? c) Someone decides to help Bob out of the water...

**physics**

Bob can swim at a rate of 5km/h. He is in a river that is flowing at a rate of 9 km/h. a) if bob swims upstream, what is his relative velocity to the ground? b)if bob swims downstream, what is his relative velocity to the ground? c) Someone decides to help Bob out of the water...

**Math**

Bob can swim at a rate of 5km/h. He is in a river that is flowing at a rate of 9 km/h. a) if bob swims upstream, what is his relative velocity to the ground? b)if bob swims downstream, what is his relative velocity to the ground? c) Someone decides to help Bob out of the water...

**Chemistry**

Why doesn't water undergo electrolysis? Why does Na2SO4 undergo electrolysis?

**trig**

verify that 2/1+cos theta - tan squared (theta/2) = 1

**Math**

Multiplying a vector by a scalar results in: a) a scalar b) a perpendicular vector c) a collinear vector c) a parallel scalar

**Math**

Sabrina and John cut a pie into 4 slices. Sabrina eats 2 slices. John eats the rest. What fraction names the part of the pie that John eats?

**Biology**

Among humans, increased interest in food intake normally occurs _____. only after the production of glucose in the liver can no longer meet metabolic needs when fewer calories are taken in than are expended, but only after the body depletes its reserves of fat in the liver via...

**SCIENCE/ earth**

Thanks Ms Sue!!!

**SCIENCE/ earth**

plate tectonics crossword puzzle what Qs and As can i use??????? PLZZZZZ HELP ME!!!!!!!!!!!!!

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