Wednesday

April 16, 2014

April 16, 2014

Total # Posts: 214

**physics**

Consider a toy car that you pullback to make it go forward. Is it a force multiplier or a distance multiplier? Defend your answer with the observations you could make

**Physics**

You pull a sled across a horizontal frictionless patch of snow. If your pulling force is in the same direction as the sled's displacement and increases the kinetic energy of the sled by 34%, by what percentage would the sled's kinetic energy increase if the pulling for...

**calculus**

At a summer campfire, the radius of a marshmallow on a stick expands at the rate of \ {r ' (t)} = \frac{2.4 }{3 t + 6} mm/s where t is the time of heating in seconds. Initially the radius was 3.8 mm. Find the radius after 16 seconds using the following steps: When substitu...

**Chemistry**

aluminum reacts with sulfuric acid to produce aluminum sulfate and hydrogen gas. how many grams of aluminum sulfate would be formed if 250 g H2SO4 completly reacted with aluminum

**Physics**

A running track consists of two straight 88.5m segments and two semicircles of radius 39.0m The distance a runner travels in one complete lap I calculated to be 422 m. How do you find the displacement in x.y of a runner who covers half a lap?

**Physics**

Meteorologists track a storm using radar. The radar shows a storm centered 30km west of town. Ninety minutes later, it's 30km north of town. Let the +x-axis point east and the +y-axis north. Assuming the storm moved with constant velocity, find that velocity.

**English Grammar**

Sorry about the typos. It should've read: They were questions submitted by others. I have to be sure to triple check before posting.

**English Grammar**

Thank you. I agree that the sentences are a bit childish. I didn't choose the wording of each sentence. They were the were questions submitted by others. I merely needed to choose the one that is grammatically correct. I just wanted a second opinion.

**English Grammar**

Which sentence uses proper grammar? I'm bored by math class. Or I'm bored of math class.

**Algebra Help**

Factor: 49^2+112r+64 =

**Chemistry**

Many portable gas heaters and grills use propane, C3H8(g). Using enthalpies of formation, calculate the quantity of heat produced when 15.0g of propane is completely combusted in air under standard conditions. Assume that liquid water is forming.

**finite math**

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**finite math**

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**finite math**

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**finite math**

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**finite math**

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**MIT 2.01X**

HW7_1B_1 : Mmax+=4000

**Physics**

HW5_4_1_b : ´-Q_2 :

**Physics**

HW5_4_1_b : ´Q_2 :

**Physics**

HW5_1_1 : 15.0 points -7 -17 HW5_1_2 : 15.0 points -3 8 HW5_2_1 : 20.0 points 1600 5600 11600 -11600 HW5_3 : 30.0 points 3.2 HW5_4_2 : 5.0 points 7 HW5_4_3 : 5.0 points -1

**Engineering**

Q1_2_3 (25/12*W*H)/A_0*E_0

**Engineering**

Q1_2 _1 400 500 699.99 665.68

**Chemistry**

Turns out all the values were right such as .02505 M and 35.45 g Cl etc, I just didn't need to multiply by 1000 and leave it in grams as you said.

**Chemistry**

To illustrate the calculation, assume that 21.95 mL of a thiosulfate solution is required to reduce the iodine liberated by 20.85 mL of 0.0200M KIO3 and that 18.63 mL of the same thiosulfate solution reacts with the iodine replaced by 20.00 mL of an unknown solution of sodium ...

**Chemistry **

Which of the following result in buffered solutions when equal volumes of the two solutions are mixed? a.) .1 M HCl and .1 M NH4Cl b) .1 M HCl and .1 M NH3 c.) .2 HCl and .1 M NH3 d.) .1 M HCl and .2 M NH3 By def. I know that a buffed solution is made from a weak base and it&#...

**Chemistry **

The question is: what is the ratio [NH3/[NH4+] in an ammonia/ammonium chloride buffer solution with pH= 10.00? (pKa for ammonia=9.25) When working the problem, I tried to solve it a bit backwards, in that I plugged in each of the multiple choices I was given to see which would...

**Chemistry **

What is the pH of a 0.1 M NaOCl solution (Ka of HOCl is 2.95 x10-8) I did: x squared/.10= 2.95x10-8 x squared= 2.95x10-9 x= 5.43x10-5 -log(5.43x10-5)= 4.27 pH However, the options I'm given are either a.) 3.74 b.) 6.47 c.) 8.23 d.) 10.27 What steps am I doing wrong?

**Chemistry **

First, the question I'm given is: What is the pH of a 1.0 L solution containing 0.25M acetic acid and 0.75M sodium acetate ( Ka for acetic acid= 1.8x 10-5) So I took the -log(1.8x10-5)= 4.74+log(.75/.25)= 5.22 pH But then I'm asked if .050 mol NaOH is added to the abov...

**Chemistry **

The indicator bromocresol green (HIn) can be in two different forms: As HIn the color of the indicator is yellow, an In the color of the indicator is blue, and an equilmolar mixture of the two species is green. The Ka of the indicator is 2.5 x 10-5. What is the color of the in...

**Chemistry **

What is the [H+] of the 0.25 M HCl solution? I'm not given a Ka value, so I'm assuming I won't need one to solve this particular problem?

**Chemistry **

When looking at a titration curve, I have to determine which is not true and I have it narrowed down to two options: The initial starting point on the titration curve is where pH depends only on [HA]0 or The finial point on a titration curve the pH depends only on [A-] I would...

**Chemistry **

When the concentration of a weak acid in solution is equal to the concentration of its conjugate base in solution, then: Would pH=pKa or would it equal pH=pKa + 1 like Henderson-Hasselbalch equation?

**True/False-2**

A function can be continuous at every point of a deleted neighborhood of some point and still not have a limit at the point which is deleted. I'm not even too sure what this means in calculus terms. Can you please explain it better? Thank you.

**True/False**

A function is continuous at a point if its limit exists at that point. I think it's false because of the counterexample of one-sided limits?

**Vertical Tangent**

lim x->0+ for 1/1+ (5^(1/x)) I think there's no limit, since there is a vertical tangent at 0, is this correct?

**Limits-Rationalizing**

I think there's no limit. Is that correct?

**Limits-Rationalizing**

lim x->1 (1-(1/x^3))/ (1-(1/x^2)) I keep seeming to get a denominator of zero when I rationalized the denominator.

**Limits-Factored?**

Thank you. I understand that it's because of the (3-x) on bottom that makes it negative?

**Limits-Factored?**

lim as x approaches 3+ x^2+x-6/18-3x-x^2 I factored it into (x+3)(x-2)/(6+x)(3-x)

**Inequalities**

Two is greater than five? That's what I do not understand.. Thank you

**Inequalities**

solve (x-3)/(x+1) > 5 I get x < -2 every time, but it doesnt work when I plug it back in. (I plugged in -5)

**Rational vs. Irrational**

Okay thank you.

**Rational vs. Irrational**

Is 3.05313131313131313131313131... irrational or rational? Thanks.

**Domain- Interval Notation**

Thank you!

**Domain- Interval Notation**

Domain of g(x) g(x)= sqrt(3-(sqrt(25-x^2)) I got -5, -4, 4, and 5. I wrote it like [-5, -4] U [4, 5] I don't think that's right?

**Chemistry**

I'm working on a problem dealing with calculating the heat of vaporization for vapor pressures problem. By substituting the problems values into the Clausuis-Clapeyron equation I get: .642= (2.28x10-5) x Delta H vap (J/mol) However, from this point I don't know how to ...

**Math**

Same kind of problem. How to rearrange to put an equation in quadratic form. Example I'm given is 49.7= 2x^2 / (1.00-x)(2.00-x) which should come out to .920x^2 -3.0x + 2.0 but I can't figure out exactly how to get to there, especially how to get the x squared number.

**Math**

Stupid question time. I need to figure out how to rearrange equations to solve for x in my chemistry homework, which involves putting equations in quadratic form first. But I can't for the life of me remember how to "rearrange" them correctly. So what in the step...

**physics**

0,0 is the origin

**physics**

A proton is put on the positive Y axis a large distance (100km) from the origin. What is the minimum speed required in the - Y direction so the proton will just reach the point (0,20) cm?

**College Physics**

So what's the minimum speed ?

**College Physics**

0,0 is the origin there is no repelling charge

**College Physics**

A proton is put on the positive Y axis a large distance (100km) from the origin. What is the minimum speed required in the - Y direction so the proton will just reach the point (0,20) cm?

**chemistry**

A sample of propane C3H8 contains 13.5 moles of carbon atoms how many total moles of atoms does the sample contain?

**Chemistry**

The molal boiling-point constant for water is 0.51 degrees C/molal. The boiling point of a 1.00 molal solution of Ca(NO3)2 should be increased by: A.) exactly 1.53 or B.) Somewhat less than 1.53 This is how I worked the problem: Ca(NO3)2 dislocates into 3 mole particles. There...

**Chemistry**

Another proposed mechanism problem: H2O2 + I ---> H2O +IO slow H2O2 + IO ---> H2O + O2 + I fast Which of the following statements in incorrect? a.) IO is a catalyst b.) I is a catalyst c.) The net reaction is 2H2O2 ---> 2H2O + O2 I would choose B, since IO is shown as...

**Chemistry**

The decomposition of ozone may occur through the two-step mechanism shown below: step 1 O3 ----> O2 + O step 2 O3 + O ---> 2O2 The oxygen atom is considered to be: a catalyst or reaction intermediate? How am I supposed to be able to tell the difference between the two? I...

**Chemistry**

Which of the following solutes, dissolved in 1000g of water, would provide a solution would the lowest freezing point? .030 mol of BaCl2, CO(NH2)2, CaSO4, CH3COOH, or .030 mol of NH4NO3 Again, the steps needed to determine for the freezing point.

**Chemistry**

Which of the following solutes in aqueous solution would be expected to exhibit the smallest freezing-point lowering (assuming ideal behavior? 0.1 m NaCl .2 m CH3COOH .05 m Al2(SO4)3 .1 m MgCl2 .25 m NH3 What would be the steps to picking the right option? Because just picking...

**Chemistry**

Which of the following pure liquids is the best solvent for sodium fluoride? CCl4 C2C6 HCl BCl3 or PCl5 My guess would be either CCl4 or C2C6, I need to know the reasoning behind the correct answer.

**Chemistry**

In a given 1st order reaction A ---> products, the initial concentration of A is 0.40 M. What will be the concentration of A after 15 seconds if the half-life of the reaction is 3 seconds? I found the concentration to be 1.25 x 10-2 M But then how do I find the rate constan...

**Chemistry**

Cyclopropane rearranges to form propene: CH2CH2CH2 --> CH2=CHCH3 by first-order kinetics. The rate constant is k = 2.74 x 10-3 s-1. The initial concentration of cyclopropane is 0.290 M. What will be the concentration of cyclopropane after 100 seconds?

**Chemistry**

The decomposition of N2O5(g) --> NO2(g) + NO3(g) proceeds as a first order reaction with a half-life of 30.0 seconds at a certain temperature. If the initial concentration [N2O5]0 = 0.400 M, what is the concentration after 120 seconds?

**Chemistry**

In a given 1st order reaction A ---> products, the initial concentration of A is 0.40 M. What will be the concentration of A after 15 seconds if the half-life of the reaction is 3 seconds?

**Chemistry**

2A + B2 + C --> A2B + BC Run # Initial Rate (M-1s-1) (A)o (B)o (C)o 1 1.6 x 106 1.2 M 1. x 10-2 M 1.0 M 2 1.6 x 106 2.4 M 1. x 10-2 M 1.0 M 3 3.2 x 106 1.2 M 2. x 10-2 M 1.0 M 4 6.4 x 106 1.2 M 1. x 10-2 M 2.0 M What would be the rate-law expression of the reaction above?

**Chemistry **

What is the vapor pressure of a aqueous solution containing 10 % (by weight) ethylene glycol (62 g/mol) at 25 °C. PH2O = 24.3 torr at 25°C?

**Chemistry **

When 1.150 grams of an unknown nonelectrolyte dissolves in 10.0 grams of water, the solution freezes at -2.16°C. What is the molecular weight of the unknown compound? Kf for water = 1.86°C/m. -2.16 x m/-1.86 = 1.16 1.16/ .010 kg of water= 116 1.150/116= 9.91 g/mol is t...

**Chemistry **

A solution contains 10.0 g pentane, C5H12, 10.0 g hexane, C6H14 and 10.0 g benzene, C6H6. What is the mole fraction of hexane? I figured the equation would be: ___ M Hexane x 10 Divided by 30 =Mole fraction of Hexane?

**Chemistry **

What mass of water must be used to dissolve 20.0 grams of ethanol, C2H5OH, to prepare a 0.0500 molal solution of ethanol?

**Chemistry **

What is the molality of an aqueous solution that is 10.0% ethanol, C2H5OH, by mass?

**Chemistry **

The rate of a reaction A ---> B is expressed by the rate expression rate=k(A)2. If the molar concentration of A is tripled, the rate of the reaction should increase by a factor of some many?

**math**

how do I write equation for the following? input a 20/28/36/44/52 output b 5/7/9/11/ ? ? is 13

**Math**

You have 2/3 bag of flour. Use 3/4 of the flour to make cookie dough. How much of the entire bag do you use to make cookie dough?

**Math**

The teacher asked Laura to give each student 2/5 sheets of paper. If there are 20 students in the class how much paper did Laura pass out?

**GRAMMAR**

WRITE AN ARTICAL ABOUT CALIFORNIA GOLD RUSH

**chemistry**

My chem book gives me the following Hess' Law example: Mg + 2HCl --> H2 MgCl2 Delta H1 MgO +2HCl --> H2O +MgCl2 Delta H2 H2 + 1/2 O2 --> H2O Delta H3=-68.3kcal The desired reaction is the formation reaction of MgO as follows: MgS +1/2 O2 --> MgO Delta H final= ...

**physics**

A weightlifter has a basal metabolic rate of 80.0 W. As he is working out, his metabolic rate increases by about 650 W. (a) How many hours does it take him to work off a 450-Calorie bagel if he stays in bed all day? (b) How long does it take him if he’s working out? (c) C...

**precalculus**

My book says a way for me to graph/plot points for my function is to write it in exponential form. For example. "Graph (fx)= log base 2(x-2) y=log base 2 (x-2) x-2=2^y x=2^y + 2 So now I can just plug any y value in to get my x value to graph my translated graph. So I was...

**precalculus **

When asked to sketch the graph of g(x)= -e^(x+1) +1, how do I turn this equation into exponential form? Or can I? I always get confused on what to do especially when I need to the x part of the equation out of the exponent.

**precalculus **

My book tells me to solve each exponential equation. I am given a lot of problems such as 6^x+1 = 4^2x-1 where I use In in the problem to help get my answer. However, in the same section, the book starts giving me problems such as 3(2)^x-2 +1=100 and .05(1.15)^x =5 etc. Where ...

**precalculus **

e^3x-7 x e^-2x =4e First step I get e^1x-7 =4e For the example in my book, the next step they divided by e. But I have no idea how to do this, or what involves?

**precalculus **

log_6(2x + 4)=2? 5 In x=10? log(x+25)=1+ log(2x-7)?

**precalculus**

No reason, basically the equation is supposed to read 3^log base 3^8?

**precalculus **

x= 3^log_3_^8 ? The log being in the exponent is throwing me off.

**Precalculus **

Solve (log x)^2 = log x Also, when will their be a possibility that an equation will have an extraneous solution? Like if you got two solutions for a log equation, will a negative solution for x automatically be extraneous?

**Pre calculus **

Okay, I'm really fuzzy about my log and exponential chapter. For example, solving some exponential equation such as e^3x-7 x e^-2x=4e I assume I start this equation by taking the natural log of both sides, but how will I know just by looking at an equation weather I need t...

**science**

What is the acceleration of a 50kg person is pushed with a force of 4N

**chemistry**

when Na compounds are heated, thy give off a light of 5890 A. If 1 x 10-4 mole of Na atoms each give off a photon of this wavelength, how many kilojoules of energy are given off?

**chemistry**

consider the following changes at constant temperature & pressure H2O(s) --yields-- H20(l); Delta H1 H2O(l) --yields-- H2O(g); Delta H2 H2O(g) --yields-- H2O(s); Delta H3 Using Hess's law, the sum of the deltas is a. equal to 0 b. sometimes greater than zero, sometimes les...

**chemistry**

since q= 100 mL x 4.18 x 8.01 =3348.18/.06= 55803. J to kJ= 55.803 should be the final answer, right? Because the answer key on my quiz says it's -55.8 kJ. I'm so confused because I thought for sure it would positive, especially since in the equation it says increases ...

**chemistry**

When 50.0mL of 1.20 M of HCl (aq)is combined with 50.0mL of 1.30 M of NaOH (aq) in a coffee-cup calorimeter, the temperature of the solution increases by 8.01 Degrees C. What is the change in enthalpy for this balanced reaction? HCl(aq) + NaOH(aq) --yields-- NaCl(aq) + H20(l) ...

**chemistry**

A 94.7 g sample of silver (s= 0.237 J/(g x Degree C)), initially at 348.25 Degrees C , is added to an insulated vessel containing 143.6 g of water (s=4.18 J/(g x Degree C)), initially at 13.97 Degrees C. At equilibrium, the finial temperature of the metal-water mixture is 22.6...

**chemistry**

I get -3113 as my answer when I plug in 30.6 as the molar mass when the teacher said it should be around -225 as the final answer?

**chemistry**

At constant pressure and 25 degrees C, what is delta H for the reaction 2C2H6(g) + 7O2(g) --yields-- 4CO2(g) + H2O(l) if the complete consumption of 11.3 g of C2H6 releases -586.3 kJ of heat energy? (11.3=.38 mol C2H6)

**math**

is 0.14 equal to 0.104

**Art**

If a painter paints 8 different pictures to get a better perspective and then only selects 1 picture to illustrate her mood: what would this be called?

**Math **

A basket containing 80 eggs weighs 2kg 300g. The same basket containing 60 eggs weighs 1kg 700g. Find the mass of the empty basket.

**healthcare management**

Write a 1,400- to 1,750-word paper on essential communication in a community crisis situation described in the scenario. Include the following in your paper: • The individuals or groups that will be communicating inside and outside the organization during this crisis situ...

**math **

Fill in the blanks with the numbers that complete the sequence, and briefly explain the rule you used 2,3,5,5,8,7,11 _,_,_,17,_,_,_ 3,4,3,4,5,3,4,5,_,_,_,_,_,7 1,2,1,1,2,3,2,1,1,2,3,4,3,_,_,1,2,_,_,_,_,_,2

**math**

yes 13,15,17,19 thanks :)