# Posts by John

Total # Posts: 8,426

**Chemistry**

Calculate deltaH for the reaction NO (g) + O (g) ----> NO2(g) given following NO + O3 ----> NO2 + O2 deltaH=-198.9 kj O3 ---> 3/2 O2 deltaH= -142 kj O2 -----> O2(g) deltaH=495

**physics**

A hoodlum throws a stone vertically downward with an initial speed v0 from the roof of a building, a height h above the ground. (a) How long does it take the stone to reach the ground? (b) What is the speed of the stone at impact? Give your answers in terms of the given ...

**physics**

A hoodlum throws a stone vertically downward with an initial speed v0 from the roof of a building, a height h above the ground. (a) How long does it take the stone to reach the ground? (b) What is the speed of the stone at impact? Give your answers in terms of the given ...

**Math Help **

I am trying to work this problem out. I know that the systematic counting principle is used. However, I cannot get the right answer. For the first part, I took R=2 N=6 6!/(6-2)! (Permutation). Answer: 30 choices for the Chair/Vice The second part, I took R=2 N=8 Combination ...

**Math**

I am trying to work this problem out. I know that the systematic counting principle is used. However, I cannot get the right answer. For the first part, I took R=2 N=6 6!/(6-2)! (Permutation). Answer: 30 choices for the Chair/Vice The second part, I took R=2 N=8 Combination ...

**its old and new at the same time.**

the answer is an idea or view.its new when you suggest bt old since it has been used somewhere else.

**riddle**

love

**math**

Two number are in the ratio 4:7 if the smallest is 36 what is the largest number?

**Math**

find f'(x) find the slope of the graph of f a x=2 and x=4 find the equations of the tangent lines at x=2 and x=4 and find the value(s) of x where the tangent line is horizontal. f(x)=2x^2+8x I found that f'(x)=4x+8 and that the slopes were 16 and 24 and the equations ...

**mathematics**

the first four terms of an arithmetic sequence are -1

**Math**

Four hours after the start of a 600 mile auto race, a driver's velocity is 150 miles per hour as she completes the 352nd lap on a 1.5 mile track a) find the drivers average velocity during the first four hours of the race. b) let f(x) represent the distance traveled (in ...

**Math**

Find the limit f(x) = -(x^2)/(x+3) a) lim f(x) x-3^- b) lim f(x) x-3^+ c) lim f(x) x-3 I know that a is dne because of the graph and that b is -infinity. And that c is dne because they are not the same. But I do not know how to do this algebraically. Thank you

**Science(physics)**

i don't know

**Calculus**

How do you find the total distance a particle travels on a given interval on a graph and net distance?

**Math **

Find the average rate of change in height of the orange from t=2 to t=5 (in feet per second) The equation is h (t)=605+15t-4.9t^2 in feet. I know the the average rate of change is change in q/ change in time. Do I put t=3 and subtract the quantity of 5 and 2 in the formula for...

**quantitative analysis for decision making**

. A food industry produces chips at three factories, located in Birmingham, Glasgow and London. Since the customer should be supplied with fresh products, these are not stored in the factories. The monthly production ability of the factory in London is 750 tones, while of the ...

**managerial Economics**

Yell-O Yew-Boats, Ltd. produces a popular brand of pointy birds called Blue Meanies. Consider the demand and supply equations for Blue Meanies: QD, x = 150 - 2Px + 0.001I + 1.5Py QS,x = 60 + 4Px - 2.5W Where Qx = monthly per-family consumption of Blue Meanies Px = price per ...

**Geometry**

A dilation scale factor 2 maps triangle RST to R'S'T'. The perimeter of triangle RST is 60. What is the perimeter of triangle R'S'T'?

**english**

can you give me a good topic for my english presentation test

**Math**

7+2+6 = 15 =17 8+ 3 + 7 =18 or maybe 8 + 2 + 7

**math**

At a basketball game, a vender sold a combined total of 116 sodas and hot dogs. The number of sodas sold was three times the number of hot dogs sold. Find the number of sodas and the number of hot dogs sold

**ss**

i need anwsers for this 1. What was the last battle associated with the War of 1812? (1 point) a.Battle of New Orleans b.Battle of "Old Ironsides"to B.attle at Montreal d.Battle at Baltimore 2. For what is the War of 1812 BEST remembered? (1 point) the Battle at New ...

**Algebra**

Mervin tells Aquilla that he has a bag with very small rocks in it. She asks how many, and he says that if you add one hundred million very small rocks to the bag, it will contain 36 more very small rocks than the number in ten thousand of the bags minus five times the number ...

**Physics wave motion**

A radar array consists of five vertical antennae arranged in a line, each emitting radio waves of frequency 120MHz in phase with one another uniformly in all directions. The spacing between each of the antennae is 8.0m. Apart from the normal direction perpendicular to the line...

**math**

The shape of a milk carton is a solid composed of a rectangular prism and a pyramid as shown. What is the formula for finding the volume of the milk carton?

**math**

1/27

**math**

A rectangular prism has a volume of 162 cubic centimeters. If the length, width, and height are reduced to 1/3 of their original size what will the new volume be?

**math**

6 cm^3

**math**

A rectangular prism has a volume of 162 cubic centimeters. If the length, width, and height are reduced to 1/3 of their original size what will the new volume be

**chemistry**

The edge of a body-centered-cubic unit cell ( which contains two atoms per unit cell) of an element Y was found to be 2.16x10^-8cm. The density of the metal is 19.35g*cm^-3. What is the approximate molar mass of Y?

**chemistry**

The edge of a body-centered -cubic unit cell (which contains two atoms per unit cell) of an element Y was found to be 3.16x10^-8cm.The density of the metalis 19.35g*cm^-3. What is the approximate molar mass of Y?

**precalculus**

Convert to Rectangular: r*tan?/sec?=2

**Algebra**

Students can buy tickets to a basketball game for $1.the addition for adults is $2 if 350 tickets were sold and the total money made was $450, how many student and adult were purchased?

**pre calculus**

In the rectangular coordinate system, each point (x, y) has a unique representation. Explain why this is not true for a point (r, ?) in the polar coordinate system.

**precalculus**

Convert to Polar: (3, -7) A) ( ?58, 337) B) ( ?58, 23) C) ( ?6, 337) D) ( ?6, 23) I do not know which is the correct answer because I worked it out and got (?58, -66.8014) Could you please tell mewhich answer is the right one

**precalculus**

Convert to Rectangular: r*tan?/sec?=2 ________________________________________ y=2 y=½ x=2 x=½

**precalculus**

can you please explain how you sketch a plane curve given by parametric equations? and explain what the orientation of a curve is?

**Chemistry Help**

You are required to make 500 mL of a buffer solution with pH = 5.0 and a total acetate concentration of 0.1000 M. You are supplied with solid sodium actetate (CH3COONa) and 2.00 M hydrochloric acid. What mass of sodium acetate and what volume of hydrochloric acid would you use...

**Calc**

A box has a bottom with one edge 6 times as long as the other. If the box has no top and the volume is fixed at V, what dimensions minimize the surface area?

**Math**

A company establishes a sinking fund in order to have 100,000 for upgrading office equipments in 4 years. If the company makes fixed monthly payments into an account paying 6.6% compounded monthly, how much should each payment be? How much interest will the account earn in 4 ...

**Math**

In the triangle ABC, AC=2cm, AB=x cm and angle ABC=?/2 rad. 1. Given that angle BAC=? rad, and that ? is a sufficiently small angle, show that x? a + b?^2, where a and b are constants to be determined. 2. For this part, ? is not assumed to be a small angle. The point N lies on...

**Math**

In the triangle ABC, AC=2cm, AB=x cm and angle ABC=?/2 rad. 1. Given that angle BAC=? rad, and that ? is a sufficiently small angle, show that x? a + b?^2, where a and b are constants to be determined. 2. For this part, ? is not assumed to be a small angle. The point N lies on...

**Calculus**

a projectile is fired vertically upward from ground level with a velocity of 1600 ft/sec. If air resistance is neglected, find its distance s(t) above ground at time t. What is its maximum height?

**Finite**

Kane Manufacturing has a division that produces two models of hibachis, model A and model B. To produce each model-A hibachi requires 3 lb of cast iron and 6 min of labor. To produce each model-B hibachi requires 4 lb of cast iron and 3 min of labor. The profit for each model-...

**maths**

A committee of 4people is to be chosen from 5 married couples. Find in how many ways the committee can be chosen if; 1) everyone is equally eligible. 2) the committee should include at least one woman

**math**

nope sorry it was me

**math**

Steve, I believe you are wrong.

**Physics**

a great of effort, time, and money has been spent in the quest for the so-called perpetual-motion machine, which is defined as a hypothetical machine that operates or produces useful work indefinitely and/ or a machine that produces more work or energy than it consumes. ...

**Physics**

the human body is only about 25 % efficient at converting input chemical energy to useful work. where does the rest of the input chemical energy go?

**Chemistry**

There was two slides over this, but they both involved one element.

**Chemistry**

Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. Calculate the density of CaF2 from these ...

**Chemistry**

Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. Calculate the density of CaF2 from these ...

**Math !!!**

(9/10)*60=a a*(2/3)=b a-b= how much time is left

**Math**

sqrt(3) * sqrt(2x+3)=sqrt(5x-6) square roots are to the 1/2 power so what you can do is square both sides 2*(1/2)= 1 so the square roots cancel. It will look like this (sqrt(3)*sqrt(2x+3))^2=(sqrt(5x-6))^2 which will cancel out all the square roots. It will end up as 3*(2x+3)=...

**Math**

Is this (2x-7x-6)/4.7 or (2x-7)/4.7 *(x-6)?

**thomas middle such**

Hundreds digit is between 1-3. Tens digits are between 6-8. The ones digit is 4-6. The total amount of digits is 11. For example, it's not 386 because the total amount is 17 (3+8+6).

**Chemistry**

Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. Calculate the density of CaF2 from these ...

**chemistry**

The average molar mass of a natural gas is 17.4g/mol consisting of CH4 and C2H6,what is the molar fraction of each gas?

**Check spanish answers**

yo anonomys i also go to connections maybe we could help each other have an email i can text to contact you?

**Chemistry**

Oops, the hydrate is Copper Sulfate Pentahydrate

**Chemistry**

A chemist takes a 647 gram sample of this hydrate. She removes all the water possible from the sample and collects it. To this water, she adds 7.6 grams of lead(II) nitrate. Afterwards she wants to precipitate all the lead. She wants to use a solution of aluminum sulfate to ...

**Chemistry**

CH4 + 2O2 --> CO2 + 2H2O a. How many grams of methane are needed to produce 1.5 X 10^-2 grams of carbon dioxide? b. How many grams of oxygen are needed to react to form the 1.5 X 10^-2 grams moles of carbon dioxide?

**Chemistry**

CH4 + 2O2 --> CO2 + 2H2O a. How many grams of methane are needed to produce 1.5 X 10^-2 grams of carbon dioxide? b. How many grams of oxygen are needed to react to form the 1.5 X 10^-2 grams moles of carbon dioxide?

**Chemistry**

CH4 + 2O2 --> CO2 + 2H2O a. How many grams of methane are needed to produce 1.5 X 10^-2 grams of carbon dioxide? b. How many grams of oxygen are needed to react to form the 1.5 X 10^-2 grams moles of carbon dioxide?

**Chemistry**

Given 1 cc of Zinc and 1 cc of Cr What is the mass difference?

**Maths**

An athlete takes 2 minutes and 15 seconds to jog around a 400m running track. At this speed, how long will it take them to run 12km

**Physics**

A 45kg skier is sliding down a 37 degree ski slope starting from rest. She crossed the 25m in 5.0s. Ignoring air resistance, Find all the forces on the skier.

**Philosophy**

Each of the underlined premises can be taken as an unacceptable premise in an argument. In each case, identify the condition of premise unacceptability Premise: Most people dislike quitters Conclusion: Therefore, I shouldn’t quit smoking I`m having trouble with this ...

**maths**

x+y+z = 180 y = 2x z =3x 6x=180 x = 30 y=60 z=90

**Math**

daniel = 3 + sam sam/daniel =4/5 sam/(sam + 3) = 4/5 5s = 4s + 12 s = 12

**Math HELP!!**

correct

**Statistics**

you roll two fair dice, a green one and a red one? (a) are the outcomes on the dice independent? (b)Find P(1 on green die and 2 on red die) (c)Find P(2 on green die and 1 on red die) (d)Find P(1 on green die and 2 on red die) or (2 on green die and 1 on red die) a)yes b)p(1)*(...

**Math**

(38.5)x>or = 4000

**math**

.25 x .25 x .25

**Algebra**

x +10 = -10 x = -20

**chem**

how many atoms are there in 0.0300 mole of methane molecules?

**(Math) PLZ CHECK ANSWERS**

1 correct 2 C 4 C 3 is there a typo?

**Statisics**

Ho: p = .24 Ha: p>.24

**english**

In which sentence is the NONESSENTIAL CLAUSE underlined? (1 point)The man leaning against the wall is from the zoo. The snake that he is holding is not poisonous. Its coloring, which is brown and green, allows it to hide in marshy areas.** That snake slithering behind the rock...

**english**

26. Which sentence correctly uses punctuation with dialogue? a. " Please be seated", my teacher said.** b. " Please be seated," my teacher said c. " Please be seated my teacher said." d. " Please be seated my teacher said". 28. Which of ...

**english**

25. which sentence is punctuated correctly? a. "Are you finished yet, Miriam asked?" b. Are you finished yet, " Miriam asked?" c. "Are you finished yet"?Miriam asked. d. "Are you finished yet?" Miriam asked.*** 26. Which sentence ...

**Math**

a parking lot has 66 parking spaces. If there are 16 more compact spaces than regular spaces. How many spaces are there for compact cars?

**Physics**

A bullet is fired with an initial speed of 200 m/s. If a target is 500ft away, at what angle should the rifle be raised in order to hit the target?

**Physical Science**

A bullet is fired with an initial speed of 200 m/s. If a target is 500ft away, at what angle should the rifle be raised in order to hit the target?

**Math**

What is the 23rd term of the sequence 2,4,6,8,

**Statistics**

(56-66)/6 = -10/6 = -1.67 95% of them so multiply .95 times 1900

**Chemistry**

I used the ideal gas law, and I got .980456 moles. then I used the equation to substitute Helium=10.0g -Krypton in the equation (x/4)+(y/83.8)=. 980456 mols for X. With a little bit of algebra, I got 6.38079g of Krypton and 3.61921g of Helium. Thanks you for the help. I wuld ...

**Chemistry**

A certain mixture of helium, He, and krypton, Kr, has a mass of 10.0 g and occupies a volume of 20.0 L at 25.0EC and 1.20 atm. What is the mass of He in the mixture?

**Science**

An automobile accelerates 1.24 m/s^2 over 6.00 s to reach freeway speed at the end of an entrance ramp. If the cars final speed is 86.0 km/h, what was its initial speed when it began accelerating? Express your answer in km/h I can do it but I just don't know how I'm ...

**english**

in which sentence is the essential clause underlined A. Eve's sister, {who loves opera,} took her to a performance B. Eve, {holding her program,} waited for the curtain to go up C. The soprano, {visiting from canada} had long black hair*** d. The person {who sells ...

**english**

21.b 22. b those was my second oppion

**english**

21. identify the appropriate punctuation for the underlined word or phrase In High School, I enjoyed reading (The Catcher in the Rye)<<underlined A. underlined B. italics c. quotation marks d. none 20. identify the appropriate punctuation for the underlined word or ...

**english**

24. identify the word or words in the sentence that need to be capitalize will you be coming o the stadium to watch the giants play sunday? a. Will,Sunday b. Will,Gaints,Sunday** C. Will D. none 23. Identify the word or words in the sentence that need to be capitalize does ...

**Math**

The daily temperature is decreasing at a rate of 2 degrees Fahrenheit T represent the daily high temperature now right then expression for the high temperature in five days the current at high temperatures need to address for hi-fi high temperature in five days check into you ...

**Chemistry need asap**

What do you mean convery each of the mols to HNO3 produced? My NO=.016 My O2=.013 My H20=.66

**Chemistry need asap**

Situation: The Production of Nitric Acid can be achieved by the following process: Nitrogen monoxide gas(NO) + diatomic oxygen gas+ water (liquid) ===> Nitric Acid (aq) a. Show complete balanced reaction for process What I have: 4NO+ 3O2+ 2H2O > 4HNO3 b. The lab ...

**Math**

5, 35, 245 can you find the other one?

**Math**

1/4= x-y 1 = 4x-4y (1-4x)/4 = y

**Math**

5(7 - 3) is this what you mean?

**Math**

L = 2w -16 2L + 2W = 100 substitute for "l" 2(2w-16) + 2w = 100 4w -32 + 2w =100 6w = 132 Can you finish from here?