# Posts by David

Total # Posts: 2,287

**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

**algebra 1**

NEED HELP!!Hi, I have been trying to figure this one math problem for awhile and I am stuck. I believe the answer is between A or B. Skip is practicing tennis serves against a wall. The distance between Skip and the tennis ball, in feet, at any time T, measured in seconds, is ...

**Algebra**

The Connecticut River flows at a rate of 3 km / hour for the length of a popular scenic route. If a cruiser to travels 3 hours with the current to reach a drop-off point, but the return trip against the same current took 7 hours. Find the speed of the boat without a current?

**math**

-5 + (x/-3) = 28

**Math**

Find the limit if it exists. lim 1/(x-2) = infinity x→2+ lim 1/(x-2) = negative infinity x→2- lim 1/(x-2) = Does not exist x→2 lim (3x+2) = infinity x→∞ lim 999/(x^3) = 0 x→-∞ Can someone check to make sure that I am correct?

**Math**

Find the limit if it exists. lim 1/(x-2) x→2+ lim 1/(x-2) x→2- lim 1/(x-2) x→2 lim (3x+2) x→∞ lim 999/(x^3) x→-∞

**Math**

Find the limit if it exists. lim 1/(x-2) x→2+ lim 1/(x-2) x→2- lim 1/(x-2) x→2 lim (3x+2) x→∞ lim 999/(x^3) x→-∞

**Math**

Ellie has 200 dollars in her wallet at 10:00 AM when she goes to the mall. Afterwards, at 4 PM she has only 5 dollars left. Is it possible that Ellie had exactly 100 dollars at one point? Explain. My guess to this question would be yes and I would use the Intermediate Value ...

**Math**

f(x) = 2x^2 x<2 4x x≥2 1. Find the slope of the tangent curve of 2x^2 at x=2. a. -1/2 b. 1/2 c. 4 d. 8 e. Does not exist 2. Find the slope of the tangent curve of 4x at x=2. a. -1/2 b. 1/2 c. 4 d. 8 e. Does not exist 3. Find the slope of the tangent curve of f(x) at x...

**Math**

5x - 3 = 7x + 11 x=-4 3w -4 = w+8 w =6 Please check. Thanks

**philosophy**

Why are philosophical questions not answered with facts?

**math**

#1 is not correct reiny lmao

**math**

#1 is not correct lmao

**english**

a letter to your uncle in american asking him to help you pay your school fees for this term.

**Chemistry**

The reaction of methyl-benzene with HNO3 in the presence of catalyst will provide what main compound?

**math**

The radius of a circle in increasing at the rate of 0.5cm/s. Find the rate at which the circumference increases if the radius in 5cm.

**Calculus**

A bucket begins weighing 30 pounds, including the sand it holds. The bucket is to be lifted to the top of a 25 foot tall building by a rope of negligible weight. However, the bucket has a hole in it, and leaks 0.1 pounds of sand each foot it is lifted. Find the work done ...

**chemistry**

1 mole ----> 24 g ? mole -----> 0.12 moles ( Mg ) = 0.12 / 24 = 0.005 moles of Mg

**Chemistry**

DrBobb22 Calcule the concentrations of Cd^+2 , [Cd(CN)4^-2] and CN^- at equilibrium, when 0.42 moles of Cd(NO3)2 dissolves in 1 L of 2.50 M NaCN Kf for Cd(CN)4^-2 is 7.1x10^16

**Chemistry**

I will post again ok?

**Chemistry**

Kf is 7.1 x 10^16

**Chemistry**

DrBobb22 Calcule the concentrations of Cd^+2 , [Cd(CN)4^-2] and CN^- at equilibrium, when 0.42 moles of Cd(NO3)2 dissolves in 1 L of 2.50 M NaCN Kf for Cd(CN)4^-2 Help!

**Chemistry**

Calculate the concentrations of Cd+2 , Cd(CN)4^-2 and CN at equilibrium when dissolvs 0.42 moles of Cd(NO3)2 (2.50 mol/L) Kf for Cd(NO3)2 = 7,1x10^16.

**Chemistry**

What volume in ml of 0.500 M silver nitrate is required to completely react with 25.0 ml of 1.5 M calcium chloride?

**Math**

f(x) = cos (1/x) Find the limit as x approaches infinity and find the limit as x approaches negative infinity. Identify all horizontal asymptotes.

**Math**

f(x) = cos (1/x) Find the limit as x approaches infinity and find the limit as x approaches negative infinity. Identify all horizontal asymptotes.

**mathematics for accounting**

the question is the formula use in calculating depreciation that is reducing balance method which is (1-n√s/c)×100/1 now we were asked to now make each of n,s,and c in the formula the subject of the formula

**math**

make each of the following the subject of the formula n,s,c in (1-n√s/c)*100/1

**Math**

f(x) = tan x / sin x Find the vertical asymptote. Describe its behavior to the left and right of the vertical asymptote.

**Chemistry**

This is the correct one because you simply just have to do a double replacement reaction. H3PO4 + 3KOH -> K3PO4 + 3 H2O

**Chemistry**

This is the correct one because you simply just have to do a double replacement reaction. H3PO4 + 3KOH -> K3PO4 + 3 H2O

**Quantitative Chemistry**

(H: +1, Cl: -1) (Mn: +4, O: -2) --> (Mn: +2, Cl: -1) (H: +1, O: -2) (Cl: 0) So, as you can see the Manganese atoms are clearly being reduced which means that it is gaining electrons, so the charge goes down. You can now eliminate choice A. Next, we can see that the charge ...

**Geometry**

Find the volume of the large solid without the smaller solid. The solid is a right solid and is not drawn to scale. Round answers to the tenths place.

**Math**

Thanks sir

**Math**

A bucket begins weighing 15 pounds, including the sand it holds. The bucket is to be lifted to the top of a 50 foot tall building by a rope of negligible weight. However, the bucket has a hole in it, and leaks 0.1 pounds of sand each foot it is lifted. Find the work done ...

**Math**

Thanks Damon!

**Math**

kinematics look easier i can do both ways but will they have different values

**Math**

its calculus but will kinetatic equations work as well?

**Chemistry**

Consider the reaction: K2S(aq)+Co(NO3)2(aq)=2KNO3(aq)+CoS(s) what volume of 0.255 M K2S solution is required to completely react with 160 mL of 0.130 M Co(NO3)2?

**Chemistry**

Thanks!!!

**History**

The answer is dessert

**Calculus 2**

Suppose that a spring has a natural length of 25 cm, and that 8 J of work is needed to stretch from a length of 50 cm to 80 cm. How far beyond its natural length will a force of 32 N keep the spring stretched? **I've tried calculating the spring constant ...

**Government**

Why people who represents special interest group received the name lobbyist ?

**Programming**

I am having a problem with something. i nead to assing values to parameters from input.dat file without using fscanf. i need to use the terminal like a.out<input.dat>output.out i have a file like this GEN 0.0 2.1351 0.00001 500 o PEND 0.12 0.1 0.15 0.5 0 0.16 0.11 0.8 -0...

**algebra 2**

Write (21 − 4i) − (16 + 7i) + 28i as a complex number in standard form.

**Chemistry**

[2.0 mol (-285.91 kJ/mol)] + [1.0 mole (0 kJ/mol)] - [1.0 mole (50.61 kJ/mol)] = ??? I came up with the answer of -622.43 but im not sure what the correct amount of significant figures would be and why? would 0 kj/mol be considered significant making the answer -600? what ...

**have got a question@sir-damon**

so how can i get the total

**maths help plz**

A certain number of children are arranged in a circular form,if they are evenly spaced,the 7th child is directly opposite to the 8th child.... how many children are their altogether? thanks

**History**

Why is the Franco-Prussian War considered an important development in the history of Europe? It was at this time that France reclaimed its military dominance in Europe. It was because of this war that Germany began its military dominance in Europe. The war allowed Prussia to ...

**History**

Use the following statement by Robert Owen to answer the question below: "...but I know that society may be formed so as to exist without crime, without poverty, with health greatly improved, with little if any misery, and with intelligence and happiness increased a ...

**Chemistry**

Thank you @DrBob222

**Chemistry**

Which is more soluble in water, Cl2 or I2?

**Essay Help**

Have you figured what to do with your comparison essay? I know it is a bit late to help you. In case somebody seeks for the help I want to assure you that you may get the assistance from the company I like. I make the grade thanks to Marvelous essay service.

**Chemisty**

Well I asked about using phenolphthalein and my teacher said that it was not a good idea. But when I was looking online, I saw some experiments using the amount of gas produced to find the amount of acetic acid in a 20Ml of vinegar in g/ml If you could tell me how this this ...

**Chemisty**

I was told to find the concentration of acetic acid in vinegar when only using baking soda and common lab equipment. Can someone tell me how Thanks

**maths help me urgently!!!!!!**

rationalise [1-(2i^2)]/i Plz help show we working so that i can learn

**Physics 1**

A textbook of mass 1.95 kg rests on a frictionless, horizontal surface. A cord attached to the book passes over a pulley whose diameter is 0.100 m , to a hanging book with mass 3.08 kg . The system is released from rest, and the books are observed to move a distance 1.27 m ...

**maths polynomial help!!!!**

x^2+2x+1 is a factor of ax^3+ax^2+bx+c then find a b c help!!

**physics**

Use conservation of energy to determine the angular speed of the spool shown in the figure below after the 3.00 kg bucket has fallen 4.05 m, starting from rest. The light string attached to the bucket is wrapped around the spool and does not slip as it unwinds. the spool, ...

**physics**

A ball bounces to 34 percent of its original height. *1) What fraction of its mechanical energy is lost each time it bounces? *2) What is the coefficient of restitution of the ball-floor system? - I was able to solve part one and get an answer of .66, but part two I don't ...

**physics**

i've tried that and it was incorrect. thanks for trying

**physics**

A ball bounces to 34 percent of its original height. *1) What fraction of its mechanical energy is lost each time it bounces? *2) What is the coefficient of restitution of the ball-floor system? - I was able to solve part one and get an answer of .66, but part two I don't ...

**trigonomentry out of ideal help ah!crying**

compute.. Cos(1degree)+cos(3degree)+cos(5degree)+...+Cos(179degree) plz show working even an hint can,t help me.Have been do maths alday my brain is fried..Ah thanks

**MAth**

Lily and rose are playing a game, in the game,each player starts with 0 points and the player with the most points at the end win. Lily gains 5 points two times loses 12 points ,and then gains 3 points. Rose loses 3 points two times,loses 1point,gains6 points another gains7 ...

**math**

I got it now. 13 combination 1. Thanks

**math**

@steve, Please I'm not clear with what you mean by 13C1. Thanks

**math**

Assuming you are listening to your favorite playlist that has 83 country songs, but your mom also added 9 pop. Suppose that shuffle mode is on - a song played is being selected at random (with replacement) from the playlist. Find the probability that, out of the next 13 songs...

**physics steve or damon help!!!!**

A stone is thrown horizontally from the top of a vertical wall with a velocity of 15m/s hit the horizontal ground at a point 45m from the base of the wall.calculate the height of the wall g=10

**physics**

Two equally long 12-cm diameter pipelines have the same pressure difference between ends. One carries a ‘Type A’ oil (𝜂 = 0.091 Pa s) and the other a ‘Type B’ oil (𝜂 = 0.064 Pa s). If ‘Type A’ oil flows at 0.14 m3/s, at which rate ...

**Physics**

A material is formed into a long rod with a square cross section 0.31 cm on each side. When a 100 V voltage is applied across a 16 m length of the rod, a 4.6 A current is carried. What is the resistivity of the material? This is a rectangular wire rather than a cylindrical. I ...

**maths geomentry help!!!**

the area of a sector PQR is a @rad.and the radius of the of the circle is rcm,the area of the sector is 20cm^2 and the perimeter is 26cm.find r?

**integration!!help urgently**

what the meaning of that box

**integration!!help urgently**

integrate:dz/(z^2+1) where z is a complex number.....plz working

**Discrete Math Help**

1) How would I prove that (n - 1 + 2 C 2) = n + (n C 2) 2) A cafeteria offers 17 types of pizza and 5 types of soda. Bob goes there everyday for lunch, always buying two slices of pizza and one soda. However, he never gets exactly the same thing on two consecutive days (that ...

**Math**

Determine the (binomial) coefficient. (x^2+3)^12; ax^8 I got 12C8 * (x^2)^4 * (3)^4 which is 40,095*x^16 but my teacher said it was incorrect. A similar problem to it was (x+3)^12; ax^5 where I determined the answer to be 1,732,105*x^5 which was correct.

**History**

Thx MS. SUE

**phi 103**

Identify the form of the following argument. Either the Pacers or the Kings will win tonight. The Pacers will win. Therefore, the Kings will not win. a. not a valid form b. disjunctive syllogism c. modus ponens d. hypothetical syllogism e. modus tollens

**Physics 1**

A 50 kg cannonball hits a war tank vehicle of 12,000 kg that is initially at rest. The cannonball embeds in the tank and both move at the same velocity for 50 cm until they both come to a rest. What is the initial velocity of the cannonball if the coefficient of friction ...