# Posts by David

Total # Posts: 2,261

**Writing help**

do you still need the help with your assignment? One of the easiest ways to help others is to simply share your knowledge. You don’t have to be in front of a classroom to teach. Every day there is an opportunity to educate someone about your area of expertise. The key is ...

**Chemistry**

Ammonium nitrate a common fertilizer was used by terrorists in the trgic explosion in oklahoma city in 1995.how many litres of gas at 307oc and 1.00atm are formed by the explosive decomposition of 15kg of ammonium nitrate to nitrogen, oxygen and water vapour Solution 2NH4NO3=...

**Physics**

This problem seems like it can be treated almost like a math problem. We know that one kilogram is equal to one-thousand grams and that one slice of ham is seven grams and two slices of bread are fifty grams total (twenty-five grams each). So you just need to see how many ...

**Physics**

We want to find which of these two elements is our limiting amount. Here's some helpful equations to consider. 8x = 32 //The equation for oxygen. 1x = 9 //The equation for hydrogen. From these two values, we want to determine the value of x that makes each equation true. ...

**Math**

// Original equation. (-i) - 2 - (6 - 4i) - (5 - 2i) // Distribute negatives. -i - 2 - 6 + 4i - 5 + 2i // Combine like terms. ((-2) + (-6) + (-5)) + ((-i) + 4i + 2i) // Solve. (-13) + 5i // Answer. 5i - 13

**Social Studies**

Oh, alright!

**Social Studies**

Yeah, that's the source I got the info from but when I tried to post the link, it told me I couldn't! Hope it was helpful, though!

**Social Studies**

McClellan ably built the army in the early stages of the war but was a sluggish and paranoid field commander who seemed unable to muster the courage to aggressively engage Confederate General Robert E. Lee's Army of Northern Virginia. So, actually, no. He wasn't ...

**math**

// FACTOR BREAKDOWN 81 = 3 x 3 x 3 x 3 27 = 3 x 3 x 3 a^3 = a x a x a a^2 = a x a b^3 = b x b x b b^2 = b x b /* For LCM, we want to consider the most number of times any digit or variable appears in the factorization. Comparing 81 and 27, we see that the number three shows up...

**science**

A steel rod of length 60 cm and radius 2.5 mm hangs vertically. If a mass of 2.5 kg is attached to the end of the rod, calculate the increase in the length of the rod

**English**

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**Chemistry 20**

a source of hydrogen is an important issue of hydrogen fuel cells are going to become useful in automobiles. What important perspective is missing?

**Chemistry 20**

If 4.56 mol of zinc react with excess copper (ii) sulphate, how many moles of precipitate will be formed?

**Math**

What is 100,000,000,000,000 times 999,999,999,999?

**English**

Is there no topic? You may come up about the story of the lost kid in the bus. Sorry,I am not that creative that is why I better go to the writers from Marvelous essay service and let them do that job for me. At least, I am sure about the high grade

**Building services**

Principles of heat: How many kilograms of water can be evaporated at 100 degrees Celsius by the combustion of 470 litres of fuel oil whose heat of combustion is 37 MJ/Litre

**Math!!!**

really have no clue

**Math!!!**

There are some hats in a box.1/6 of them are red, 1/3 are blue, and 3/7 of the remainder are green. If there are 27 green hats, how many hats are there altogether?

**Math !!!**

15/30 of the savings is left

**Math !!!**

Kieth spends 1/6 of his savings on a magazine and 2/5 of the remainder on a book. What fraction of his savings is left?

**Math !!!**

Tony is given 9/10 hour to mow a lawn. He only uses 2/3 of the given time to mow the lawn. How much time is left?

**Math !!!**

Tian has 56 paper clips. He gives 3/4 of them to Joe. Joe gives 2/7 of what he receives to Rahul. How many paper clips does Rahul get?

**Math**

A child releases a balloon from a height of 6ft and it ascends at a rate of 5ft per second. A second balloon starts at a height of 51 ft and descends at a rate of 2 ft per second. After how many seconds will both balloons be at the same height above the ground.

**Algebra**

Thank you for your help.

**Algebra**

A tank contains 150 gallons of water and fills at a rate of 8 gallons per minute. A second tank contains 600 gallons of water and drains at a rate of 10 gallons per minute. After how many minutes will both tanks have the same amount of water?

**Algebra**

Thank you

**Algebra**

A child releases a balloon from a height of 6ft and it ascends at a rate of 5ft per second. A second balloon starts at a height of 51ft and ascends at a rate of 2ft per second. After how many seconds will both balloons be at the same height above the ground?

**Math**

At the market, 0.2 of the pieces of fruit are peaches, 0.25 is apples, 0.05 is lemons, 0.1 is cherries, 0.2 is grapes, and 0.15 is plums. There are also 8 pineapples and 4 mangos. How many peaches are for sale at the market? How many apples? How many lemons? How many plums?

**Math**

One-quarter of Steve's baseball cards are from his dad's collection. Another 0.2 are from his uncle, and 0.5 are from his brother. The rest are from Steve's cousin. Thirty of the cards from his cousin are National League players; the other half are American League...

**Math**

How could Jason solve for T in this equation? T - 8 = 40 A) add 8 to the left side B) add 8 to the left side and subtract 8 from the right side C) add 8 to each side D) divide each side by 8

**Math**

What should Edna do to solve for m in the equation? 65 = m + 29 A) add 29 to each side B) add 29 to the left side C) subtract 29 from the right side D) subtract 29 from each side

**Math**

In a class where there are as many girls as boys, 2/5 of the boys and 1/2 of the girls went to a local fair. What fraction of the students in the class did not go to the local fair?

**Math**

Alvin has some marbles in a box. He keeps 1/3 of them and gives the remainder to Joyce and Sean. Joyce gets 5/8 of the remainder. What fraction of the marbles does Sean get?

**Science**

I may advise you where to go to have the report and coclusion written. The writers from Marvelous essay service help me all the time and I want you to have your work done by them. I am sure that you will be satisified

**Math**

Find the sum of each series by using appropriate formulas. Show your work. MY WORK: (N is the last number in the sequence) 1+2+3+...+230 n(n+1)/(1*2) 4+8+12+...+360 n(n+4)/)4*2) 1+3+5+...+123 ((n+1)/2))^2 The problem: 53+59+65+...+233 n(n+6)/(6*2) 233(239)/12 = decimal??? ...

**Physics 1**

a 12.5 m long string vibrates as 100 hertz standing wave with nodes at 1.0m and 1.5m from one end of the string and at no points in between the two. Which harmonic is this? What is the string's fundamental frequency?

**AP Cemistry**

Calculate the heat that must be supplied to 10.5 g of Ne(g) at 0.15 atm to raise its temperature from 24◦C to 54◦C at constant pressure. Assume that neon behaves as an ideal gas. Answer in units of J. [So, I know that we would use q = mCDT at some point but because...

**math**

Was this perhaps a typo? Did you mean that Aaron split TEN pencils between seven people? It wouldn't make sense for Aaron to break a pencil into seven chunks and hand them out to his friends.

**math**

This is a simple division problem with an expected remainder: 82 / 7 = 11 boxes + 5 crackers leftover. We can't expect a decimal in this sort of problem so we consider how many 7's can FULLY go into 82 and then subtract that total when no more 7's fit. So, 82 ...

**physics**

Please refer to my post on your earlier question.

**English**

"Look at this picture of John." and "Look at this picture of John's." are both correctly written sentence. The first implies that the picture has John on it. It was a picture taken of him. The second sentence implies possession. The picture belongs to ...

**physics**

Considering that the speeds are in two different units, we have to convert. The conversion rate from km/h to m/s is 1 to 0.277778. So the car's speed is 15 m/s. The distance between the car and the truck is 60000 m. This problem can be solved using a system of equations. ...

**Math**

Assuming that the goal here is to just solve for each variable, this goes back to basic algebra and it's highly suggested that you refer to your notes. Regardless, SOLVING FOR Z ORIGINAL EQUATION: (z / 12) = 9 (1/12) * z = 9 //A variable divided by anything can be replaced...

**Algebra**

This problem works off of the relationship between two equations. In this case, the equations represent the two offered fitness plans. We will start by setting up our two equations: y = 30x + 50 y = 40x Our goal is to find when the first option will come out to be better in ...

**Math**

Is the number of total shots Ryan made a given? Otherwise, there is no way to figure this out. In any case, if we know that Ryan made 60% of all shots he made, that must mean that the other 40% of shots he made were foul (assuming that this means "missed shots"). All...

**AP Chemistry**

So my work then came out to be this, but proved to be wrong. //Chemical Equation CH4(g) + 202(g) = CO2(g) + 2H20(l) //Gallons -> Liters 94 x 3.785 = 355.79 //Liters -> Mililiters 355.79 * 1000 = 355790 //Mililiters -> Grams (Density) a = 355790g H2O //Delta ...

**AP Chemistry**

A typical bathtub can hold 94 gallons of water. Calculate the mass of natural gas that would need to be burned to heat the water for a tub of this size from 59 ◦F to 101 ◦F. Assume that the natural gas is pure methane (CH4) and that the products of combustion are ...

**algebra**

To find the distance between two points (x1, y1) and (x2, y2), all that you need to do is use the coordinates of these ordered pairs and apply the formula: Distance = √((x2 − x1)^2 + (y2 − y1)^2) So, in using this formula, we find that: 1. The distance ...

**Science**

An astronomical unit is a unit of measurement equal to 149.6 million kilometers, the mean (average) distance from the center of the earth to the center of the sun.

**math**

The parabola whose equation is 4y^2+3x=2+8y, determine the co-ordinates of the focus, equation of the directrix and the length of the latus rectum?

**Algebra**

Country A has a growth rate of 4.7% per year. The population is currently 5,646,000 and the land area of Country A is 13,000,000,000 square yards. Assuming this growth rate continues and is exponential, after how long will there be one person for every ...

**Math**

A rectangle, a circle and a triangle are drawn in a plane. What is the maximum number possible points of intersection. The sides of the triangle are not collinear with any of the sides of the rectangle.

**Algebra**

Country A has a growth rate of 2.6% per year. The population is currently 4,069,000 and the land area of Country A is 33,000,000,000 square yards. Assuming this growth rate continues and is exponential, after how long will there be one person for every ...

**Math**

Find two algebraic expressions for the area of each figure. First, regard the figure as one large rectangle, and then regard the figure the figure as a sum of four smaller rectangles t,5,t,3

**History**

Thank you so much! I'm behind a lot in World History.

**Math**

What is the equivalent ratio in simplest form of 45 books in 90 minutes if she organized 120 books.

**Science, NATS**

Consider the following chemical reaction. Molecular hydrogen and carbon dioxide react to form water and methane. H2+CO2-->H2O+CH4 A)Explain why this equation is not balanced and what law of nature does it break in its current form? B) Astronauts from the Earth carry large ...

**math**

4 t shirts. 2 sandals

**math**

After 5 seconds

**Math**

13.64 minutes

**Math**

1.25L of water

**math**

mamta read 2/5 of a book on monday and 3/8 of the remaining book on tuesday.find the part of the book left unread after tuesday find the total no of pages in the book if 48 pages are left unread.

**Social studies**

Life expectancy What two countries are not part of Africa?

**maths**

How many even numbers can be formed from the digits 1,2,4,4,7,8,9 Is it 2160 ( 6! * 3)

**Math**

75 red ballons

**history,college**

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**Maths ( permutation and combination)**

a town council plans to plant 12 trees along the centre of a main road.It has 4 hibiscus trees, 6 Jacaranda trees, 2 oleander trees. How many different arrangements of these 12 trees can be made if no hibiscus tree is next to another

**Psychology**

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**maths**

If it takes 10 men to build a house in 6 months how many men would be needed to build it in 4 months

**maths need help**

x^(e^3x)^x Find the derivative of that please show working thanks

**World History**

Thanks so much nikki! I can verify Nikki's answers are correct I just took the test and got a 100%

**integrated science**

A planet is 2.45 x 10^9 km away. How long would it take in hours to travel to the planet at the speed of light? (speed of light is 2.998 x 10^8 m/s)

**math**

100 student appeared in class test for a combined english and hindi examination. 70 students passed in both,8 failed in english and hindi and 5 failed in hindi only find how manystudents failed in english and how many students passed in hindi also find how many students passed...

**Math**

Eduardo has a red 6-sided number cube and a blue 6-sided number cube. The faces of the cubes are numbered 1 through 6. Eduardo rolls both cubes at the same time. The random variable X is the number on the red cube minus the number on the blue cube. What is P(−2≤X...

**Chemistry**

Calculate how many grams of the substance and how many grams of water is in a solution of 400g with a concentration of a 30%

**Chemistry**

Calculate the mass of the precipitate formed when 2.27 L of 0.0820 M Ba(OH)2 are mixed with 3.06 L of 0.0664 M Na2SO4.

**Chemistry**

How many mL of 0.1 N NaOH are required to react with 100 mEq of H2SO4?

**Chem**

Write a chemical formula. . . Ca2+ and S2-

**Chem**

Consider the following equation in chemical equilibrium C2H4(g) <--> C2H6(g) + 137 kJ What happens to the ethane (C2H6) when the temperature of the system is increased

**maths**

The function f is such that f(x)= (2 - x)^2, x belongs to real number. Find g and h as functions of x such that gh(x)=f(x)

**computer ( theory )**

A designer wishes to include some multimedia components on a web page. a) If the designer has some images stored in files, there are two possible formats for the files.. i) Describe the approach used if a graphic is stored in a vector graphic file ii) Describe the approach ...

**CHEMISTRY**

I didn't understand the mass M2CO3 titrated = 7.46 x (25/1000) step. please, could you explain

**CHEMISTRY**

A solution of a metal carbonate M2CO3, was prepared by dissolving 7.46 g of the anhydrous solid in water to give 1000cm^3 of solution. 25.0cm^3 of this solution reacted with 27.0cm^3 of 0.100 mol/dm^3 hydrochloric acid. Calculate the relative formula mass of M2CO3 and hence ...

**Organic Chemistry**

Suppose 5.00 gram of a mixture of aspirin, caffeine, and acetanilide was dissolved in enough solvent (methylene chloride) to make a total of 100.00 mL volume. You took 10.00 mL from it and isolated its components using the same protocol you did in the lab. You obtained: ...

**Geometry**

If the width and height of a rectangular prism are each shrunk to one seventh of the original size but the length remains the same, what is the formula to find the modified surface area?

**math**

Find the smallest positive integer not relatively prime to 2015 that has the same number of positive divisors as 2015.

**math**

If I am traveling at 60mph and you are traveling at 30mph how many minutes until we meet?

**math**

Marta’s math textbook weighs mc017-1.jpg of a pound less than 4 times the weight of the book she is reading for her language arts class. If the weight of the math textbook is mc017-2.jpg pounds, which shows the correct equation and value of x, the weight of Marta’s ...

**Parametric Equations**

For the set of parametric equations x = 2t+1 and y = t^2-5, name the initial point on the graph on the interval -5<t<5. a. (-9, -30) b. ( -5, 5) c. (11, 20) d. (-9, 20) (I chose this one)

**Math**

What must be true about the solution to this system of equations? x+4y+9z = -96 -2y+9z = -47 z = -7 a) The solution will describe the intersection point(s) of the 3 graphs. b) The value of z must be -7. c) The solutions will have values for x, y, and z. d) All of the above ...

**math**

A rectangle has a width of 15 inches and a diagonal of 17 inches. Find the length of the rectangle in inches. 15^2 + b^2 = 17^2 225 = b^2 = 289 0 + b^2 = 289 – 225 B^2 = 64 B = SQRT of 64 = 8 The length of the rectangle in inches equals 8 inches.

**math**

A suitcase measures 22 inches long and 16 inches high. What is the diagonal length of the suitcase to the nearest foot. 16^2 + 22^2 = C^2 256 + 484 = C^2 740 = C^2 SQRT of 740 = 27.20 in. The diagonal length to the nearest foot equals 2.26ft.

**math**

A suitcase measures 22 inches long and 16 inches high. What is the diagonal length of the suitcase to the nearest foot. 16^2 + 22^2 = C^2 256 + 484 = C^2 740 = C^2 SQRT of 740 = 27.20 in. The diagonal length to the nearest foot equals 2.26ft.

**Math**

A hat contains 3 marbles; one green, one blue, and one orange. Two marbles are selected at random without replacement from the hat. a) Determine the number of points in the sample space. b) Determine the probability of selecting exactly 1 ...

**My brain is hurting please help?**

At a homeowners' association meeting, a board member can vote yes or on a motion. There are three motions on which each board member must vote. Complete parts (a) through (c) below. (a) Determine the number of points in the sample ...

**Math**

Find the indicated probability. If P(A or B)equals=0.7 P(A)equals=0.3 and P(A and B)equals=0.15 find P(B). P(B)equals=

**Science**

Why are boats more efficient than airplanes? They use less fossil fuels to move

**Math**

One thousand raffle tickets are sold for 1 dollar each, one prize of 800.00 dollars is to be awarded. Rene Condos purchases one ticket a) Determine her expected value? b) Determine the fair price of a ticket?

**Prosbility**

One thousand raffle tickets are sold for 1 dollar each. One price of 800.is to be awarded. Rena Condos purchases one ticket? Determine her expected value Determine the fair price of the ticket 1/800 1 dollar

**Physics**

8kg mass moving with a speed of 30 of 30ms-1 is brought to rest in 2.5sec, calculate the magnitude of the constant retarding force