# Posts by luke

Total # Posts: 417

**Chemistry**

Use the ion-electron method to write and balance the net ionic equation for each of the following reactions. MnO41- + Sn(OH)31- MnO2 + Sn(OH)62- in basic solution MnO41- + (COOH)2(aq) Mn2+ + CO2(g) in acidic solution I2(aq) + S2O32- I1- + S4O62- Zn(s) + HgO(s) ZnO(s) + Hg(l) ...

*March 21, 2017*

**science**

h(t) = 20t - 5t^2 max height is at t=2 h(2) = 40-20 = 20

*March 18, 2017*

**Urgent math question help!!!**

Drag and drop the correct justifications into the boxes. 4(x?2)+1=9 : subtraction property of equality 4x?8+1=9 :combine like terms 4x?7=9 : distributive property 4x = 16 : associative property of equality x = 4 : division property of equality

*March 2, 2017*

**Chemistry Help**

The most effective buffer solutions have equal concentrations of salt and acid (or base). Find the pH of a buffer solution with equimolar concentrations of: (a) HCOOH and NaCOOH (Ka = 3.5 x 10-4 for HCOOH) (b)CH3NH2 and CH3NH3Cl (Kb = 3.7 x 10-4 for CH3NH2) Thank you!

*February 23, 2017*

**Maths**

Make h subject of formula in A=?r?h²-r²

*February 17, 2017*

**math**

A concert arena has 48 rows, each with 8 seats and another 54 rows, each with 9 seats. How many seats does the concert arena have?

*January 9, 2017*

**Calculus**

A chemical substance is draining from a conical filtering system at a rate of 100 cubic centimeters per minute into a cylindrical storage tank below. The conical filter and cylindrical tank each have a diameter of 60 centimeters, and the height of the cone also measures 60 ...

*December 19, 2016*

**chemistry**

1. Silicon dioxide reacts with carbon upon heating to produce silicon carbide (SiC) and carbon monoxide. SiO2(s) + 3C(s) = SiC(s) + 2CO(g) a. What mass of carbon is required to react completely with 15.70 g of SiO2? b. When 152 g of SiO2 reacts with excess carbon, what mass of...

*December 13, 2016*

**math**

She would get 0 Rs. You would have to work backwards. The equation would be R= rina's Rs 300*3-100=R

*December 13, 2016*

**Anyone good with probability??**

It would be Mark because a coin has two sides, 50/50 chance for a head or a tail.

*December 13, 2016*

**Trig identities**

Has a negative -5/13 Steve. If angles x and y are in the same quadrant and sin x =3/5 and cos y= -5/13 determine the value of sin (x-y)

*December 8, 2016*

**Trigonometric identities**

If angle x and y are in the same quadrant , and sin x=3/5 and cos y=5/13, determine the value of sin(x-y) .

*December 8, 2016*

**science**

A solution of aqueous ammonia contains 28.0% NH3 by mass. the solution has a density of 0.898g/mL. calculate the volume of this solution required to make 425mLof 0.320M NH3 solution.

*November 18, 2016*

**math**

Which expression shows 27 + 36 as the product of their greatest common factor and the sum of two whole numbers with no common factor? 7(4+5)7(4+5) 9(4+5)9(4+5) 9(3+4)9(3+4) 7(3+6)7(3+6)

*October 11, 2016*

**Haematology**

Define terms: - clinical conditions - pathological conditions - physiological conditions These terms have me confused..

*October 8, 2016*

**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 don't 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*

**Art**

Anonymous is correct thx

*February 16, 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*

**Art plz correct me!!!**

The Answer is A

*February 5, 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*

**History**

No it actually was a study guide unit 4 now

*October 15, 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*