Wednesday
August 24, 2016

Posts by luke

Total # Posts: 392

Chemistry
A 2.80-g sample of haematite ore containing Fe3+ ions was dissolved in a concentrated acid and the solution was diluted to 250 mL. A 25.0 mL aliquot was reduced with Sn2+ to form a solution of Fe2+ ions. This solution of Fe2+ ions required26.4mL of a 0.0200 M K2Cr2O7 solution ...
August 23, 2016

Chemistry
If a current of 3.00 A is applied to a cell containing a 400g copper anode, determine the final mass of the copper anode after the cell runs for 48.0h
July 11, 2016

Chemistry
If a solid state lithium battery produced 5.00 mA in 8.25 h, then the mass, in milligrams, of lithium consumed would be?
July 11, 2016

english
death?
June 27, 2016

Physics
A rock is thrown straight up at 22.0 m/s from a roof of a 30.0 m tall building. After rising, the rock falls on the street below. Ignoring air resistance, how much time is the rock in the air? Show the work please :)
May 24, 2016

English
thanks for the help reed
May 19, 2016

English
he blinded the cyclops, sorry I get it now Poseidon was his dad
May 19, 2016

English
ya i read the story a while ago, but what does the cyclops dad have to do with this question?
May 19, 2016

English
I'm confused
May 19, 2016

English
How does the boldness Odysseus shows in the Cyclops’s cave drive subsequent plot events? A)Several of Odysseus’s men are eaten. B)Odysseus and his men spend the night in the Cyclops’s cave. C)Odysseus gives the Cyclops wine to drink. D)Odysseus and his men blind...
May 19, 2016

Algebra
Two numbers add up to 20. The sum of their square is 20 less than 3 times their product. Formulate equations and find the numbers. I know the first equation (x+y=20), but i dont know the second one.
May 19, 2016

calc 2
the function g(x)=x^2+5x, x>=p is one to one. find the least value of p, the range of g, sketch the graph of this function.
March 26, 2016

math
If y varies directly as the square root of x and y = 47 when x = 49, find y if x = 2401. (Round off your answer to the nearest hundredth.)
March 10, 2016

Physics
5. A grating with 400 lines per mm is illuminated with light of wavelength 600.0 nm. (a) Determine the angle at which the maxima are observed (b) Determine the largest order (n) that can be seen with this grating and this wavelength.
March 9, 2016

Maths
From a group of 10 people, 5 men and 5 women, six are to be chosen to serve on a committee. a) In how many ways can the committee be chosen? b) Find the probability that two men will be chosen. c) Find the probability that the committee chosen will consist at least 4 women.
March 9, 2016

math
how does a rodeo star get around?
March 2, 2016

Maths
Two tetrahedral dice are thrown; one is red and the other is blue . The number on which each lands is noted, the faces being marked 1,2,3,4. Find the probability that the sum of the numbers on which the dice lands is 6 given that the red die lands on an odd number.
February 14, 2016

Chemistry
Fe2O3 + Fe + H2SO4 → FeSO4 + H2O How would I balance this using oxidation numbers? Is the Fe2 being reduced and the Fe being oxidized?
December 8, 2015

Physics
Two buckets of sand hang from opposite ends of a rope that passes over an ideal pulley. One bucket is full and weighs 110 N ; the other bucket is only partly filled and weighs 65 N . You release the lighter bucket and the heavier one descends. What is the tension in the rope?
November 8, 2015

Math
in a class, 3/5 of the girls and 1/6 of the boys wear spectacles. If 3/4 of those who are wearing spectacles are girls, what fraction of the pupils does not wear spectacles?
October 5, 2015

Math
-1.4b + 10= -18
October 5, 2015

science
Which physical properties are characteristics of metals? Choose all that apply. -brittle -high luster -malleable -ductile -not very reactive 1, 2, and 5?
September 24, 2015

Science
Pineapple has high requirements for the fertilizer elements nitrogen (N), potassium (K), and iron (Fe), and relatively low requirements for the fertilizer elements phosphorus (P) and calcium (Ca). Although Hawaiian pineapples grow in red soils whose iron composition may exceed...
September 14, 2015

Math
How do I find the vertical and horizontal asymptotes of f(x)= (x+2)/(5x^2) Wouldn't one of them be (I,-I)? How do I solve this? Thank you!
September 8, 2015

Calculus 1
Find the volume of the solid obtained by rotating the region under the graph of the function f(x)=2x+1 about the x-axis over the interval [0,1]. I have no clue how to start this..... :(
August 6, 2015

math
The scale model of a rectangular patio will be enlarged by a scale factor of 2.5 to create the actual patio. The actual patio will be 15 feet by 20 feet. Which is the area of the scale model? 48 square feet 60 square feet 120 square feet 300 square feet
July 20, 2015

Math
5 cos x + 2 = 0 5 cos x = -2 cos x= -2/5 arccos (-2/5) = answer (check to see if you are supposed to answer in degrees or radians - change calculator settings accordingly)
June 7, 2015

Statistics
A roulette wheel has 38 slots, numbered 0, 00, and 1 to 36. Two slots are green, 18 of the others are red, and 18 are black. a) What is the probability of winning with a bet on red in a single play of roulette? b) You decide to play roulette 4 times, each time betting on red. ...
June 7, 2015

Math
One phone company charges $12 per month plus $.05 per minute after the first 500 minutes. A second phone company charges $10 per month plus $.04 per minute after the first 300 minutes. How many minutes would a subscriber have to use so that the cost of the two plans is the ...
May 18, 2015

English
Thank you so much for explaining, and thank you for the website. I saved the link and will be using it this quarter as I take my English class. :-)
April 26, 2015

English
I added words instead of a comma because there aren't multiple elements in a series or coordinate adjectives, there aren't two independent clauses, there are no introductory or parenthetical elements, nothing is quoted, there is no confusion, and there are no phrases ...
April 26, 2015

English
Is this better? At elementary school, my teacher delighted in handing me worksheets that were crowded with row upon row of three-to-five digit long division problems.
April 26, 2015

English
Ok, I hyphenated the words "three-to-five digit." But the rules say that a word that modifies the adjective and not the object should not have a comma separating the modifier and the adjective it modifies. In my sentence, I have the phrase "row upon row of three...
April 26, 2015

English
Is this sentence punctuated correctly? At elementary school, my teacher delighted in handing me worksheets crowded with row upon row of three to five digit long division problems.
April 26, 2015

calc
If a cost of a function is C(x) = (49 ln x) / (28-3x), find the marginal cost when x = 7
April 18, 2015

algebra
find 3 consecutive integers such that the sum of the squares of the first and second is 2 more than the third
April 10, 2015

Math
The curves y=sinx and y=cosx intersects twice on the interval (0,2pi). Find the area of the region bounded by the two curves between the points of intersection.
March 1, 2015

Chemistry
A student was required to prepare 250.0 mL of a hypochlorous acid/sodium hypochlorite buffer in which the concentration of the weak acid component was 0.073 M and the concentration of the conjugate base was 0.046 M. The student was supplied with 0.365 M hypochlorous acid and 1...
February 5, 2015

geometry
I am given triangle EDF with angles E and F being congruent. What is the perimeter of the triangle if ED= 2x+8, EF= 3x-6, and DF= 4x-6.
January 18, 2015

math
5.6 lb/gal = oz/gal
December 13, 2014

Geometry
Carl is looking to buy a farm. While looking at a potential property, Carl wants to know the height of the silo. He measures a nearby tree to be 8ft. When he stands 25ft away from the silo and 2 ft away from the tree, he can see the silo in the distance. His eyesight is 5 ft ...
December 11, 2014

AP Calc
Ok so i set y=(4x)^1/2 Using the distance formula... i got it down to d=((x-8)^2+((4x)^2)^1/2 Took the derivative and got dy/dx=2x+1/((x)^1/2)-16
November 22, 2014

AP Calc
Find the point on the curve y^2=4x closest to the point (8,0). My Work: Using the Distance formula- my answer i got was (7.821,5.593) but idk if i did it right...
November 22, 2014

AP Calc
Oh so then i plug x=6 back to the original to get Y
November 22, 2014

AP Calc
Find the point on the curve y^2=4x closest to the point (8,0). My Work: Using the Distance formula- my answer i got was (7.821,5.593) but idk if i did it right...
November 22, 2014

AP Calc
Thanks so much i understand it now :)
November 22, 2014

AP Calc
A rectangle is inscribed into the region bounded by the graph of f(x)=(x^2-1)^2 and the x-axis, in such a way that one side of the rectangle lies on the x-axis and the two vertices lie on the graph of f(x). What is the maximum possible area of such a rectangle? My Work: y=(x^2...
November 22, 2014

statistics
Thanks alot! Could you possibly elaborate as to how you approach this type of problem?
October 6, 2014

statistics
Five cards are drawn from a standard deck, what is the probability of picking 3 face cards?
October 6, 2014

statistics
Five cards are drawn from a standard deck, what is the probability of picking 3 face cards?
October 6, 2014

multiplying fractions
2/11 * 264 = 528/11 Is the answer correct?
September 24, 2014

multiplying fractions
Thank you just making sure.
September 24, 2014

multiplying fractions
5/7 * 9/10 = 9/14 Should my answer be 45/70 or 9/14?
September 24, 2014

english
which poem has the rhyme scheme AA BB CC
September 19, 2014

8th grade math
3.16•10^3 in standard form is 3.16•1000 which is 3160. The Real Answer is: 3160
September 7, 2014

Logic / Discrete Mathematics
@MathMate Thank you so much! No wonder I was going nowhere even when I did the truth table, I had a mistake in translating the proposition. Thanks again.
September 1, 2014

Logic / Discrete Mathematics
Show that "¬p Λ q is logically equivalent to p → ¬q" . I'm not sure if the conditional identity is correct, but what I did was I negated the whole second condition and it immediately became equal to the first? Please help and if possible, show ...
September 1, 2014

Physics ASAP
A proton, traveling with a velocity of 6.8 × 106 m/s due east, experiences a magnetic force that has a maximum magnitude of 8.6 × 10-14 N and direction of due south. What are the magnitude and direction of the magnetic field causing the force? If the field is up, ...
August 3, 2014

Physics
A proton, traveling with a velocity of 6.8 × 106 m/s due east, experiences a magnetic force that has a maximum magnitude of 8.6 × 10-14 N and direction of due south. What are the magnitude and direction of the magnetic field causing the force? If the field is up, ...
August 2, 2014

Chemistry
Benzene reacts with hot concentrated nitric acid dissolved in sulfuric acid to give chiefly nitrobenzene, C6H5NO2. A by-product is often obtained, which consists of 42.86% C, 2.40% H, and 16.67% N (by mass). The boiling point of a solution of 5.5 g of the by-product in 45 g of...
July 15, 2014

Chemistry
A saturated solution is made by dissolving 0.252 g of a polypeptide (a substance formed by joining together in a chainlike fashion some number of amino acids) in water to give 1.92 L of solution. The solution has an osmotic pressure of 3.69 torr at 25 °C. What is the ...
July 15, 2014

Chemistry
So would you do M=RT/Pi M=(301 x .08205)/.005 4939.41?
July 14, 2014

Chemistry
A saturated solution is made by dissolving 0.325 g of a polypeptide (a substance formed by joining together in a chainlike fashion some number of amino acids) in water to give 1.37 L of solution. The solution has an osmotic pressure of 4.13 torr at 28 °C. What is the ...
July 14, 2014

Chemistry
HOW DO I FIGURE OUT THE MOLECULAR FORMULA FROM THE DATA?
July 14, 2014

Chemistry
So would the molar mass be 168.2? Empirical be c3h2n1o2?
July 14, 2014

Chemistry
What is the molar mass of the by-product? Calculate the molecular formula of the by-product. Calculate the empirical formula of the by-product.
July 14, 2014

Chemistry
Benzene reacts with hot concentrated nitric acid dissolved in sulfuric acid to give chiefly nitrobenzene, C6H5NO2. A by-product is often obtained, which consists of 42.86% C, 2.40% H, and 16.67% N (by mass). The boiling point of a solution of 5.5 g of the by-product in 45 g of...
July 14, 2014

Chemistry
How do I solve for the y? I get 0.2=23.71g / 24.71+.281 Y. Y But I don't know how to solve
July 14, 2014

Chemistry
At 21.0 °C, a solution of 23.71 g of a nonvolatile, nonpolar compound in 30.64 g of ethylbromide, C2H5Br, had a vapor pressure of 319.7 torr. The vapor pressure of pure ethyl bromide at this temperature is 400.0 torr. Assuming an ideal solution, what is the molecular mass ...
July 14, 2014

Chemistry
A solution of acetic acid, CH3COOH, has a concentration of 0.218 M and a density of 1.00 g mL-1. What is the molality of this solution?
July 14, 2014

Chemistry
Thank you! It was right!!!
July 9, 2014

Chemistry
A mixture of ammonia and oxygen is prepared by combining 0.250 L of NH3 (measured at 0.700 atm and 20°C) with 0.160 L of O2 (measured at 0.720 atm and 49°C). How many milliliters of N2 (measured at 0.740 atm and 100. °C) could be formed if the following reaction ...
July 9, 2014

Chemistry
Methane is formed in landfills by the action of certain bacteria on buried organic matter. If a sample of methane collected from a landfill has a volume of 200. mL at 741 torr and 27.2 °C, how many grams of methane are in the sample? I get the PV=nRT p is 741/760= .975 V ...
July 9, 2014

Chemistry
Around 514.58?
July 8, 2014

Chemistry
How many milliliters of O2 are consumed in the complete combustion of a sample of hexane, C6H14, if the reaction produces 325 mL of CO2? Assume all gas volumes are measured at the same temperature and pressure. The reaction is 2C6H14(g) + 19O2(g) -> 12CO2(g) + 14H2O(g)
July 8, 2014

Chemistry
A mixture of ammonia and oxygen is prepared by combining 0.330 L of NH3 (measured at 0.790 atm and 22°C) with 0.210 L of O2 (measured at 0.820 atm and 48°C). How many milliliters of N2 (measured at 0.740 atm and 100. °C) could be formed if the following reaction ...
July 8, 2014

Chemistry
p2=.792atm x 683mL/ 292.15 x 349.15/733mL I got .882 and it says it wrong. Do you know what I done wrong?
July 8, 2014

Chemistry
When a sample of neon with a volume of 683 mL and a pressure of 0.792 atm was heated from 19.0 to 76.0 °C, its volume became 733 mL. What was its final pressure (in atm)?
July 8, 2014

Chemistry
so could I solve like n=.975atm *.200L * (300.2/.08205)? 713.45 and thank you for your help!
July 8, 2014

Chemistry
so .975 x 200mL = n x .08205 x 27.2?
July 8, 2014

Chemistry
What would my R be? 741torr x 200mL=nR X 27.2
July 8, 2014

Chemistry
Methane is formed in landfills by the action of certain bacteria on buried organic matter. If a sample of methane collected from a landfill has a volume of 200. mL at 741 torr and 27.2 °C, how many grams of methane are in the sample?
July 8, 2014

Chemistry
A mixture of N2, O2, and CO2 has a total pressure of 928. torr. In this mixture the partial pressure of N2 is 31.0 cm Hg and the partial pressure of O2 is 4.00 dm Hg. What is the partial pressure of the CO2 (in torr)?
July 8, 2014

Chemistry
Thank you!
July 1, 2014

Chemistry
24) It was found that a 20.00 mL portion of a solution of oxalic acid, H2C2O4, requires 6.69 mL of 0.200 M K2Cr2O7 for complete reaction in an acidic solution. In the reaction, the oxidation product is CO2 and the reduction product is Cr3+. How many milliliters of 0.450 M NaOH...
July 1, 2014

Chemistry
18) Aspirin is a monoprotic acid called acetylsalicylic acid. Its formula is HC9H7O4. A certain pain reliever was analyzed for aspirin by dissolving 0.534 g of it in water and titrating it with 0.0446 M KOH solution. The titration required 26.73 mL of base. What is the ...
July 1, 2014

Chemistry
Thank You!!!
July 1, 2014

Chemistry
12) Naturally occurring argon is composed of 0.3365% of 36Ar (atomic mass, 35.9675 u), 0.0632% of 38Ar (atomic mass, 37.9627 u), and 99.6003% of 40Ar (atomic mass, 39.9624 u). Use these data to calculate the average atomic mass of argon.
July 1, 2014

Chemistry
13) Mercury is an environmental pollutant because it can be converted by certain bacteria into the very poisonous substance dimethyl mercury, (CH3)2Hg. This compound ends up in the food chain and accumulates in the tissues of aquatic organisms, particularly fish, which renders...
July 1, 2014

Chemistry
14) A lawn fertilizer is rated as 7.04% nitrogen, meaning 7.04 g of N in 100 g of fertilizer. The nitrogen is present in the form of urea, (NH2)2CO. How many grams of urea are present in 100 g of the fertilizer to supply the rated amount of nitrogen?
July 1, 2014

Chemistry
How many grams of water could have its temperature raised from 25 ºC (room temperature) to 100 ºC (the boiling point of water) by the amount of energy released in the formation of 4.0 mol of H2 from hydrogen atoms? The bond energy of H2 is 435 kJ/mol. The specific ...
June 29, 2014

Chemistry
Some time ago, a U.S. citizen traveling in Canada observed that the price of regular gasoline was 0.771 Canadian dollars per liter. The exchange rate at the time was 1.401 Canadian dollars per one U.S. dollar. Calculate the price of the Canadian gasoline in units of U.S. ...
June 29, 2014

Chemistry
Use an enthalpy diagram to calculate the lattice energy of CaCl2 from the following information. Energy needed to vaporize one mole of Ca(s) is 192 kJ. For calcium, the first IE = 589.5 kJ mol-1, the second IE = 1146 kJ mol-1. The electron affinity of Cl is -348 kJ mol-1. The ...
June 29, 2014

Chemistry
In the spectrum of a specific element, there is a line with a wavelength of 656 nm. Use the Rydberg equation to calculate the value of n for the higher energy Bohr orbit involved in the emission of this light. Assume the value for the lower energy orbit equals 2.
June 29, 2014

Chemistry
Microwaves are used to heat food in microwave ovens. The microwave radiation is absorbed by moisture in the food. This heats the water, and as the water becomes hot, so does the food. How many photons having a wavelength of 3.00 mm would have to be absorbed by 1.45 g of water ...
June 29, 2014

Chem
How much methane, in grams, must be burned to release 542 kJ of heat? H=-802kJ
June 26, 2014

Chem
How much heat (in kilojoules) is liberated by the combustion of 7.01 g of magnesium? Include the sign in your answer. H+-1203kJ
June 26, 2014

Chemistry
When 4.76 g of a solid mixture composed of NH4Cl and CaCl2 was dissolved in 100.0 mL of water, the temperature of the water rose by 4.73°C. How many grams of each substance was in the mixture?
June 26, 2014

science
An unsecured astronaut is floating in deep space. He switches on a hand held drill. The drill bit begins rotating clockwise with high angular velocity. Describe what happens to the astronaut- drill system and explain why.
June 5, 2014

Math problem or trick
if 60% of students in the class were wearing sport shoes and 40% dress shoes, does it mean that everybody in the class were wearing shoes?
May 16, 2014

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