Sunday
December 21, 2014

Posts by martin


Total # Posts: 183

Chemistry
What is the molarity of 35.0 of NaCl in 125 mL of water?
November 10, 2014

phsics
a man weighs 1370N on earth what would he weigh on jupiter where free fall acceleration is 25.9 m/s2 the acceleration of gravity is 9.8 m/s2 in units of N
November 2, 2014

Chem
Solid urea, (NH2)2CO, burns to give CO2,N2, and liquid H2O. Its heat of combustion is -632.2 kJ/mol. Balance the equation for combustion of urea, and calculate the heat generated per mole of H2O formed. (Enter in kJ.)
October 23, 2014

physics
A 2.40 kg firecracker explodes into two pieces and produces 170 J of heat, light, and sound energy. One of the pieces has a mass of 0.800 kg and a speed of 4.50 m/s after the explosion. If the mass of the other piece is 1.20 kg, what is its speed after the explosion?
June 20, 2014

Math
would it be negative 17?
March 13, 2014

Math
Write an integer that is represented by the bold words in the following sentence. The temperature dropped 17 degrees between noon and midnight.
March 13, 2014

functions
What is the rule for input 0 output -1
February 25, 2014

Math
An investment was worth $1000. By the end of 2010 the investment had lost 30%. What percent must the investment grow by in 2011 to be worth $1000 by the end of 2011? Round your answer to the nearest tenth of a percent.
January 29, 2014

Math
7.99 meters or 8.01 meters
January 29, 2014

History
What would Jackie Robinson (might) accomplish as president of USA
January 20, 2014

Physics
Yep, 8*10*-6 is the answer. A square loop of wire of side L with total resistance R moves at constant speed v into a region of uniform magnetic field B pointing perpendicular to the plane of the loop. What is the average current that is induced. Iave=BL^2/R is that the answer???
December 12, 2013

english
2. Tecumseh's "Let the white race perish" speech is A. a logical list of reasons why the whites should be resisted. B. a satire on the white race and its traditions. C. a plea to the people's reason. D. an appeal to the emotions of his listeners.
September 18, 2013

COMM100
Which of the following would be an appropriate way to use the DECIDE tool in response to research suggesting that there are differences between the way men and women communicate?
September 6, 2013

Math
The number N of state and federal inmates in millions during year x, where x>2002 can be approximated by the following formula N=0.04x-79.02
July 18, 2013

Physics
A race car starts from rest in the pit area and accelerates at a uniform rate to a speed of 35 m/s in 11s, moving on a circular track of radius 500 m. Determine the tangential and centripetal components of the net force excreted on the car(by the ground) when it's speed is...
May 19, 2013

Physics 1
I'm sorry when it's speed is 15 m/s. doesn't say uniform
May 18, 2013

Physics 1
(I) determine the tangential and centripetal components of the net force excreted on the car(by the ground) when it accelerates at a uniform speed of 15 m/s in 11 s, moving on a circular track of radius 500m. The cars mass is 1100kg.
May 18, 2013

Physics 1
(I) determine the tangential and centripetal components of the net force excreted on the car(by the ground) when it accelerates at a uniform speed of 15 m/s in 11 s, moving on a circular track of radius 500m. The cars mass is 1100kg.
May 18, 2013

Math/ Calculus Help1
Supplies are dropped from a stationary (not moving up or down) helicopter and, after some amount of time, land on the ground with a velocity of -160 feet per second. Assumptions: Start time at t = 0 and ignore air resistance. Recall that the height function is given by y(t)= ...
April 16, 2013

CHEM
Yes, I can use the Ka of HClO. (hypochlorite ion from hypochlorous) HClO is a weak acid with a Ka of 2.9*10-8 The pKa = 7.54 (-log of the Ka) Since the concentration ratio is equal to 1 and the log of 1 is zero, the pH would equal the pKa. Please verify
April 13, 2013

CHEM
How can I calculate a pH of hypochlorite buffer into LiCLO with only initial concentrations and no Ka value? [CLO-]=.1M [LiCLO]=.1M
April 13, 2013

math
what would 1.25 be as a fraction?
March 26, 2013

math
can you divide a fraction into another fraction?
March 26, 2013

English paper 3
Write a dialogue in wich you convince your teacher that you are too sick to participate in sports for thed day
March 17, 2013

English paper 3
An discursive essay of this topic , both parrents should assume equal responsibility in raising a child,agree or dis agree
March 17, 2013

Sciience
Do you know what is qualitative data?Please help me
March 10, 2013

Math help please!!
Given: angle A is 20˚, b = 50 cm, for what possible range of lengths of side “a” would triangle ABC have two possible solutions (approximate to 2 decimal places)?
January 20, 2013

MATH HELP!!!
Given: A is 20˚, b = 50 cm, for what possible range of lengths of side “a” would ABC have two possible solutions (approximate to 2 decimal places)?
January 20, 2013

chemistry
Is 39.2 in KJ/mol? please help
January 12, 2013

science
please drwls, what is the answer of a and b
January 12, 2013

chemistry
50 g Si doped with 27g Sb
January 12, 2013

Chemistry
1KJ/mol=1.03*10^-2EV please somebody tell about b
January 11, 2013

Chemistry
somebody please tell the answer of b. I tried with all equation. D=D0e^-Ea/RT Created Eq.1 for 35+273K and Eq.2 for 45+273k i got Ea 1.55*10^4J/mol even after conversion with j/mol to EV not getting green check 1KJ/mol=1.03*10^-2 if some body got green check please suggest me.
January 11, 2013

Chemistry
what would be answer of b. would it be 45
January 11, 2013

Chemistry
someone please help regarding answer of a and b. 18 is not showing green check
January 11, 2013

Chemistry
rufus, please what is answer
January 11, 2013

Chemistry
chacho,could you please explain the answer when de broglie wavelength 0.468*10^-10m.
January 11, 2013

chemistry
1ev= 1.69*10^-19 J
January 11, 2013

chemistry
39.2 is wrong answer. could you please help for the answer of b
January 11, 2013

Chemistry
could any one help me regarding correct answer of this question
January 11, 2013

Chemistry
Anonymous, could you please explain the answer. the answer you mentioned is wrong
January 11, 2013

math
If you borrow $15,000 from your dad for college and you agree to pay him $25,000 back at 8% compound interest per year. How many years do you think you have to do this? In other words, given the amounts and the interest rate, what is the number of years?
October 9, 2012

Percentage
The usual price of a suitcase was $100. During a sale, a 13% discount was given. Mr Lee bought the suitcase but had to pay 7% GST on the selling price. a.) What was the selling price of the suitcase? b.) How much did Mr Lee pay for the suitcase?
October 8, 2012

AP Chemistry
If 15.0mL of 2.50M NaCl is mixed with 60.0mL of 0.300M Pb(NO3)2, what is the mass of the precipitate
October 4, 2012

MATH
Use a table of trigonometric values to find the angle è in the right triangle in the following problem. Round to the nearest degree, if necessary. cos è=? A=22 H=38
July 17, 2012

chemistry
Hvap 40.65 kJ/mol Hf -285.83 kJ/mol Hfusion 6.03 kJ/mol specific heat 4.186 J/gC molar mass 18.02 g How much energy is consumed by thawing 4.3 g ice?
June 28, 2012

chemistry
Hvap 40.65 kJ/mol Hf -285.83 kJ/mol Hfusion 6.03 kJ/mol specific heat 4.186 J/gC molar mass 18.02 g How much energy is consumed by thawing 4.3 g ice?
June 28, 2012

physics
given that the mass of an electron is 9.1 x 10^-28 grams and the charge on an electron is 1.6 x 10^-19 Coulombs, calculate the voltage required to lift an electron 5 cm. the question was previously answered, but I did'nt understand it .. could some show me again please.
May 19, 2012

physics
Hi Damon .. where did the 10^-3 come from? .. I understand the 9.8 is gravity and the 5 is 5 cm
May 19, 2012

physics
Given that the mass of an electron is 9.1 x 10^-28 grams and the charge on an electron is 1.6 x 10^-19 Coulombs, calculate the voltage required to lift an electron 5 cm. not quite sure how to do this.
May 19, 2012

physics 30
A flash of lightning transfers 1.5 x 10^9 Joules of energy through a potential difference of 5.0 x 10^7 Volts between a cloud and the ground. Calculate the quantity of charge transferred in the lightning bolt. How many electrons were transferred? Does this get easier? I hope so.
May 19, 2012

Physics 30
Hello damon... I'm not sure what happened there... what happened to the 5.0 x 10^-6 Could you show me again, as I don't quite understand it. thanks martin
May 19, 2012

Physics 30
A test charge of 5.0x10^-6 C is moved 2.0 cm through an electric force of 6.0 x 10^-7 N . What is the change in evergy of the test charge? What is the change in voltage on the charge? Help
May 19, 2012

science
how does the moon move through space ?
May 15, 2012

Math
3x2x4
May 8, 2012

math
write three ways to find 3x2x4
May 5, 2012

physics
Consider a system of N identical particles. Each particle has two energy levels: a ground state with energy 0, and an upper level with energy . The upper level is four-fold degenerate (i.e., there are four excited states with the same energy ). (a) Write down the ...
March 11, 2012

math
solve the system 7x^2 - 5y^2 + 20y = 3 21x^2 + 5y^2 =209
March 10, 2012

mechanics
Two 20kg weights are hung from light strings that pass over frictionless pulleys. The ends of the strings are connected to a small, light spring balance, S, calibrated in kg. The pulley axes are mounted on the wall of a lift in a 50-storey building. What is the reading on the ...
March 7, 2012

Basic Statistics
In each of the following situations state whether or not the given assignment of probabilities to individual outcomes is legitimate, that is, satisfies the rules of probability. If not, give a reason a) roll a die and record the count of spots on the up-face P(1)=0 P(2)=1/6 P(...
March 2, 2012

geometry
A ball gas a radius of 56mm (a)Calculate the surface area (b)What is the volume of the sphere
February 28, 2012

psy230
don't know
February 16, 2012

Arithmetic
Given the sequence Tq=-7+3(q+4) find T4,and x if Tx=50.
January 21, 2012

arithmetic
The nth term of the sequence 4,11,18,...is167 find n
January 21, 2012

phycis
A roller coaster has two hills and starts from rest atop the first hill , which is the higher of the two hills . The secound hill increases if the height of the initial hill is increased by 20m
December 28, 2011

Chemistry
I don't understand the part when it says 100-X/X. How do you solve for X?
December 7, 2011

Chemistry
A rock contains 200. µmol 238U (t1/2 = 4.5 109 yr) and 116 µmol 206Pb. Assuming that all the 206Pb comes from decay of the 238U, estimate the rock's age. Please explain step by step.
December 7, 2011

Math
Suppose R is the relation on N where aRb means that a ends in the same digit in which b ends. Determine whether R is an equivalence relation on N. And, Suppose that R and S are equivalence relations on a set A. Prove that the R ¿ S is also an equivalence relation ...
November 18, 2011

Discrete Math
You have two decks of 26 cards. Each card in each of the two decks has a different letter of the alphabet on it. You pick at random one card from each of the two decks. A vowel is worth 3 points and a consonant is worth 0 points. Let X = the sum of the values of the two cards ...
November 15, 2011

Discrete Math
How many ways can you get a bunch of 4 books to give a friend if you have 30 books (15 novels, 10 history book and 5 math books)?
November 1, 2011

chemistry
NaOH + CH3COOH = CH3COONa + H2O calculate the mass concentration in gdm-3 of the orinigal viniger
October 27, 2011

psychology
Kevin and Cheryl had completed their first day of naturalistic observation of adolescents at the local high school. As they discussed their experiences during the day, they found that they were both concerned about the difference their presence in the classrooms made on ...
October 25, 2011

Chemistry
Thank you Dr. The former is needed to find the volume of H2 in this case. I expect that once I perform the lab, the latter will be needed. You've helped me a great deal. You may expect to see me more often. I'm in your care for this semester, amongst any other ...
October 22, 2011

Chemistry
Dr, I have another question, but first, thank you for showing me that I was on the right track. I didn't understand how the moles of HCl were distributed. I thought .02 moles of HCl meant that there were .02 moles of H and .02 moles of Cl. Now I know that HCl add up to .02...
October 22, 2011

Chemistry
How many mole of H2 will be produced if 0.500 grams of magnesium is reacted with 10.00mL of 2.0 M HCl? I've concluded the answer is 0.02 moles of H2, but I'm doubting myself a lot because I don't understand the aspects of the balanced chemical equation and how that...
October 22, 2011

Physcial Science
Alpha particle tracks through gases and thin metal foils show few deflections. What does this tell us about the atom?
October 2, 2011

Physical Science
What fuel other than uranuin can be used in a nuclear reactor?
October 2, 2011

Math
Cause i wasnt really sure
September 15, 2011

Math
Is it possible to find out how long is the wall? The choices shown for the problem are: (a) 8 feet (b) 12 feet (c) 14 feet (d) 15 / 9 feet (e) None of these. Because I had put down (e) none of these.
September 15, 2011

Math
A scale drawing of an office building is not labeled but indicates 1 / 3 inch = 4 feet. On the drawing one wall measures 4 and 2 / 3 inches. How long is the wall?
September 15, 2011

Physics
What's the acceleration you're told to use in your class? 9.8m/s^2? 10m/s^2? 9.81m/s^2? I'll go with 10 because I'm lazy, just substitute to whatever you guys are using. The first ball (dropped from rest) will take 2 seconds to reach the ground : 20 = 5 x t^2 ...
August 28, 2011

Physics
x = x0 + v0*t + 1/2*a*t^2 x0=1.5 v0=-3 a=-10 (or something close, depending on what you're told to use in your class). You want the time for when x=0 (where 0m = the bottom of the window). 0 = 1.5 - 3 x t - 5 x t^2 1.5 = 3xt + 5xt^2 0=5t^2 +3t -1.5 You use the quadratic ...
August 28, 2011

Accounting
You didn't actually ask a question. Just saying.
August 28, 2011

Math
First, count the number of p and y in one pattern. Then, multiply these respective numbers by 4 because you need 4 times these patterns for one necklace. Then you multiply by 8 because you want 8 such necklaces. One pattern : y=4, p=10 One necklace : y = 4 x 4 = 16, p = 10 x 4...
August 28, 2011

algebra
variance = 4, so standard deviation = 2 (because squareroot of 4 is 2) 160 - 166 = -6 = -3 standard deviation. You take out a normal distribution table and you find out that a standard deviation of -3 or less happens only 0.13% of the time. Answer : 0.13%
August 27, 2011

algebra
230% of the distance from Boston to St. Louis = 2.3 times the distance from Boston to St. Louis With that information, you have that : 2.3 x (distance from Boston to St. Louis) = 2410 And you just divide both side of the equation by 2.3. 2410 divided by 2.3 is very close to 1048.
August 27, 2011

basic statistics for the behavioral sciences
a) 11 + 1 (you) = 12. 12/80 = 0.15 = 15% b)40% = 0.4, 0.4 x 80 = 32. c) 7.5% = 0.075, 0.075 x 80 = 6 Also, 0.5% x 80 = 0.005 x 80 = 0.4 students, which doesn't make sense.
August 27, 2011

alegbra
0.82 - 0.8 = 0.02 0.02/0.01 = 2 standard deviations You check a normal distribution table (unless you were provided with the value for 2 standard deviation already) You get : Greater than 2 standard deviation = 1 - 0.9772 = 0.0228
August 27, 2011

math
At T=0, which is when we're in 1991, we want E(0)=73.7. The slope in front of T is found as follow : (76.9 - 73.7) divided by (1997-1991) = 0.53333~ = 8/15 This mean thay the life expectancy would increase by 8/15th of a year every year. In short, E(T) = 8/15 x T + 73.7 ...
August 27, 2011

Geometry
A side has 5x5=25 square feet. A box has 6 sides. 6 x 25 = 150 square feet. 4 cents per foot : 150 x 4 = 600 cents = $6 per boxes 100 boxes : 6 x 100 = 600$ total. Those are some costly boxes. Then again, they are very big boxes.
August 27, 2011

math
Stop spamming, I already answered you.
August 26, 2011

math
Just try them quickly, there's a more formal method, but it'd be much more complicated for such a simple problem. They want only even numbers. You can quickly see 10 x 12 = 120 is smaller than 224 and 18 x 20 = 360 is too big. You're left with 12 x 14, 14 x 16, etc...
August 26, 2011

math
14 and 16.
August 26, 2011

Geometry
Well, the only thing I can see "lacking" in the definition is if the intersection P is actually also one of the A,B,C,D points. So you could just say ""If line AB and line CD intersect at point P such that P is different from A, B, C or D, then angle APC ...
August 26, 2011

trig
Cot (theta) is just 1/(Tan(theta)). So we have 0.05 = 1/(Tan(theta)) And thus, by multiplying both side by Tan(theta), we have : 0.05 x Tan(theta)= 1 So Tan(theta)= 1/0.05 = 20 Tan (theta) = 20
August 26, 2011

statistics
1) 300 is two deviations of 50 away from 200, so the standard score is 2. 2) You need to look at a normal distribution for this. A quick google search should help you just fine. Or, possibly, you were provided one in class. From such a table, you can see that being two ...
August 26, 2011

alegbra
PsyDAG is wrong, I believe. The odds are 1/(10,000+1) or 1/10,001.
August 26, 2011

5/90 lotto winning numbers
LOTTERY IS A MYSTERY THAT NEEDS LOT OF RESEARCH AND TOP CONNECTIONS.
July 14, 2011

Chemistry
A reaction proceeds according to the following mechanism: Cl2 ⇌ 2 Cl (fast equilibrium) Cl + H2 ⇌ H2Cl (fast equilibrium) H2Cl + Cl → 2 HCl (slow) What is the rate law for this reaction?
June 25, 2011

Chemistry
Consider the voltaic cell: Zn(s) / Zn2+(aq) // H+(aq) / H2(g) / Pt(s) Calculate the value of Ecell, in V, when [Zn2+] =1.00 M and [H+] = 0.00100 M DATA: Zn2+(aq) +2 e¯ ---> Zn(s);Eo = - 0.76 V 2 H+(aq) + 2 e¯ ---> H2(g);Eo = 0.00 V
June 19, 2011

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