Saturday

May 23, 2015

May 23, 2015

Total # Posts: 108

**chemistry 30**

Calculate the enthalpy of reaction for the combustion of ethene.
*March 9, 2015*

**Algebra II**

From 1990-1994 the mail order sales of health products can be modeled by S= 10t^3+115t^2+25t+2505 where S is the sales (in millions) and t the number of years since 1990. In what year were about $3885 million health products sold.
*March 1, 2015*

**Chemistry**

jbkl
*February 22, 2015*

**English**

n.scott momaday
*February 3, 2015*

**physics / astronomy **

A simple temperature model for the solar nebula disk is ￼Tdisk(a) = 20 × SQRT 100 AU/ a K, (1) where a should be expressed in AU in this equation. ￼(a) Find the temperature in the solar nebula disk at the orbit of Mer- cury, Earth and Jupiter. (b) Where is ...
*November 13, 2014*

**physics**

did you ever get the answer?
*January 20, 2014*

**PHYSICS**

5 kg cart is at the bottom of a 10 m hill. For the cart to reach the top of the hill, what is the minimum kinetic energy of the cart?
*January 16, 2014*

**Math**

then...
*December 8, 2013*

**Math**

when a number is multplied by itself the result is equal to 7 times twice the number. What is one possible value of the number So n^2= 7 x 2n? Then can't 0 be one?
*July 15, 2013*

**Math**

In a circle gray showing world population of aluminum, what is the measure of the central angle of the sector representing a country that produces 4/15 of the total world production of aluminum? A 26 B 60 C 85 D 92 E 96
*July 15, 2013*

**Math**

if the sum of the positive integers x and y is 12 then x can be equal to all of the following except 5y 4y 3y 2y y
*July 15, 2013*

**Math**

alex estimates that if he lies in the sun for k hours it will take him (10+10k) to get to sleep at night because of the sunburn . If Alex wants to get as much sun as possible without taking more than half an hour to get to sleep, how many HOUR CAN he lie in the sun? A 1/2 B 1 ...
*July 15, 2013*

**Math**

That makes so much sense now, thank you.
*July 15, 2013*

**Math**

3,4,9,12,16,18 two integers are related if they share a factor other than 1. which of the following numbers is related to every number in the list above. A 10 B 9 C 6 D 4 E 3 Is it 10? Since like 30,40,90,120,180 all have factor of 10?
*July 15, 2013*

**MATH**

A basket contains the following pieces of fruit: 3 apples, 2 oranges, 2 bananas, 2 pears, and 5 peaches. Jonas picks a fruit at random and does not replace it. Then Beth picks a fruit at random. What is the probability that Jonas gets a peach and Beth gets an apple?
*April 11, 2013*

**math**

ok thx
*March 6, 2013*

**math**

is it 108
*March 6, 2013*

**math**

Find the volume of a square pyramid with a base length of 9 cm and a height of 4 cm. 324 cm3 108 cm3 36 cm3 152 cm3 miss sue do you think it could be c
*March 6, 2013*

**Basketball Current Event**

The Miami Heat has recently played. Use Google for more info.
*February 18, 2013*

**science**

convection and conduction
*February 6, 2013*

**Chemistry**

yes, we need help
*January 11, 2013*

**CHEMISTRY**

Firstly, why is your caps lock on. Secondly, asking a question is not spamming on a Q&A website. Asking many questions is fine. It just shows how you have no respect to other people, and that questions are only important if they are relevant to you. If someone has a lot of ...
*January 11, 2013*

**chemistry**

You stupid person. If someone has a lot of legitimate questions, they have a lot of questions. It is not spamming at all, it is asking for help. This website is about answering questions. If someone has a lot of questions, you should try and answer them, not delete their ...
*January 11, 2013*

**Biology**

See how ridiculous this is? Would you want such a response to one of your questions? No you would not.
*January 11, 2013*

**Biology**

STOP SPAMMING
*January 11, 2013*

**Chemistry (balloon)**

A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.7 kg m-3. Under these conditions the total surface area of the balloon is 0.52 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1. Calculate the rate of ...
*December 15, 2012*

**Chemistry**

A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.7 kg m-3. Under these conditions the total surface area of the balloon is 0.52 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1. Calculate the rate of ...
*December 14, 2012*

**High School Physics**

The player kicks a football with an initial speed of v0 = 98 ft/s. Determine the two possible values for the angle of the kick, theta. The distance of the football field is 126 ft. Also determine the corresponding time at each of these two angles.
*October 25, 2012*

**High School Physics**

The player kicks a football with an initial speed of v0 = 98 ft/s. Determine the two possible values for the angle of the kick, theta. The distance of the football field is 126 ft. Also determine the corresponding time at each of these two angles.
*October 25, 2012*

**.**

What are 2 causes and 2 effects of the development of ancient civilizations in the Middle East.
*October 11, 2012*

**Physics **

Two students are on a balcony 22.3 m above the street. One student throws a ball, b1, vertically downward at 19.2 m/s. At the same instant, the other student throws a ball, b2, vertically upward at the same speed. The second ball just misses the balcony on the way down. (a) ...
*October 10, 2012*

**AP Physics**

Three blocks of masses 8.2 kg, 5.88 kg, and 2.19 kg are connected by light strings that pass over frictionless pulleys as shown in the ﬁgure. The acceleration of the 5.88 kg block is 2.18 m/s 2 to the left and the surfaces are rough. The acceleration of gravity is 9.8 m...
*February 5, 2012*

**physics**

u aint cool u dont know anything u GOT IT WRONG!!!!!!!!!!!!
*January 30, 2012*

**physics**

thank you so much! <3 =))))))))))
*April 4, 2011*

**physics**

The football is kicked over the goalpost with an initial velocity of vA=32 m/s as shown. Determine the point B (x,y) where it strikes the bleachers. type this question to google to find the figure. please and thank you.
*April 4, 2011*

**chemistry**

What is the percent composition of O in C8H8O3
*March 10, 2011*

**chemistry**

When the following equation is balanced the coefficient of CaO is ... CaO + P4O10 > Ca3(PO4)2
*March 10, 2011*

**Physical Education**

u should use the seel format
*March 2, 2011*

**Physics**

That neighbor's pesky kid now has new missiles that make elastic collisions. He insists on throwing 25.0 g rocks at your new 2.25 kg light fixture hanging by a 26.0 cm wire from the ceiling of your porch. If each rock strikes the fixture traveling at 10.0 m/s, how high ...
*October 17, 2010*

**Chemistry**

imgur>com?4wBfp>jpg (change ? to / and > to . ) In the picture above, why does the second stereocenter have an S configuration and not an R? Based on priorities / atomic weights: OH (left) = 1 CH2OH (bottom) = 2 CH3 (top) = 3 H (right) = 4 Since the lowest priority ...
*October 10, 2010*

**Physics**

My answer was 19.8 cm but it was incorrect. A basket of negligible weight hangs from a vertical spring scale of force constant 1500 N/m. If you suddenly put a 3.00 kg adobe brick in the basket, find the maximum distance that the spring will stretch. Answer: 3.92 cm If, instead...
*October 9, 2010*

**Physics**

No cheating
*October 6, 2010*

**Physics**

No Cheating
*October 6, 2010*

**Physics**

Can anyone answer part 3 for me? I've tried so many incorrect answers that I've already given up: 1.00, 1.50, 2.00, 3.00, 9.40 Question: A slingshot obeying Hooke's law is used to launch pebbles vertically into the air. You observe that if you pull a pebble back 2....
*October 5, 2010*

**social studies**

what are some major characteristics in the eastern hemisphere?
*October 3, 2010*

**Physics**

Some sliding rocks approach the base of a hill with a speed of 11.0 m/s. The hill rises at 44.0 degrees above the horizontal and has coefficients of kinetic and static friction of 0.410 and 0.630, respectively, with these rocks. 1) Find the acceleration of the rocks as they ...
*September 30, 2010*

**Physics**

I solved part A but not part B: A batted baseball leaves the bat at an angle of 35.0 degrees above the horizontal and is caught by an outfielder 370 ft. from home plate at the same height from which it left the bat. Part A: What was the initial speed of the ball? Answer: 34.3 ...
*September 25, 2010*

**Physics**

A current of a river flows steadily from west to east at 1.00 m/s. A boat in the river travels at 3.00 m/s relative to the water. The river is 20.0 m wide with parallel banks. The boat leaves the shore at point A, and point B is directly across the river from that point. 1) At...
*September 19, 2010*

**Physics**

I solved 1 out of 2 correctly: A shell is launched at 140 m/s 56.0 degrees above the horizontal. When it has reached its highest point, it launches a projectile at a velocity of 110 m/s 35.0 degrees above the horizontal relative to the shell. 1) Find the maximum height (in m) ...
*September 19, 2010*

**Physics**

How would I approach this problem? What formula would I use to answer each part? Thank you in advance for any guidance... As part of the launch of the space shuttle, solid-rocket boosters (SRBs) first take it to an altitude of 45.0 km while they accelerate it to a speed of ...
*September 19, 2010*

**Physics**

A shell is launched at 140 m/s 56.0 degrees above the horizontal. When it has reached its highest point, it launches a projectile at a velocity of 110 m/s 35.0 degrees above the horizontal relative to the shell. 1) Find the maximum height (in m) about the ground that the ...
*September 18, 2010*

**Physics**

An air-conditioner unit is fastened to a roof that slopes upward at an angle of 37.0 degrees. In order that the unit not slide down the roof, the component of the unit's weight parallel to the roof cannot exceed 560 N. What is the maximum allowed weight of the unit, in N? ...
*September 17, 2010*

**Physics**

I have already solved 2 out of 3 questions: Your spaceship lands on an unknown planet. To determine the local value of g, you ask a steel-toed crew member to kick a stone, and you find that if she kicks it at 16.0 m/s at various angles, the maximum range she can achieve is 32....
*September 17, 2010*

**Math**

Difficult conversion problem---imgur*com#Ojmb7*jpg (replace * with . and # with / to get proper URL...sorry about the extra work but this site isn't letting me post links)
*September 7, 2010*

**Math**

How do you factor this completely? 6x-x^3-x^2
*June 14, 2010*

**Trigonometry**

Verify the identity. sin2x/cosx + sinx = 2sinx Solve for all values of x: 6cos2x-7cosx-3=0 If f(x)=cos1/2x-sin2x find the value of f(pi)
*April 20, 2010*

**Trigonometry**

Prove it is an identity. (sin^2x)/(tanx)=sinxcosx
*April 19, 2010*

**Trigonometry**

How do I solve these? 1) 2sinxcosx-cosx=0 2) cos^2(x)-0.5cosx=0 3) 6sin^2(x)-5sinx+1=0 4) tan^2(x)+tanx-12=0
*April 18, 2010*

**Spanish**

How do you say... 1. We brushed our teeth and ate breakfast. 2. We took the bus to the zoo.
*April 2, 2010*

**Math**

Solve the system of equations y=3x x^2-y=28
*March 24, 2010*

**chemistry**

How many moles of O2 are needed to combine with 0.288 mol Al to give Al2O3?
*March 15, 2010*

**Math**

1-m/m÷m-1/m
*March 10, 2010*

**Math**

Simplify: 1-m ——— m ————— m-1 — m
*March 10, 2010*

**Chemistry**

Nevermind, I got it. It was simply 100g minus 2g of NaCl (mass of the solvent, water).
*January 26, 2010*

**Chemistry**

So how many grams and moles of water will I use? I know water is missing compound and for the molality calculation, how many will I use? 1 gram and then covert that to kg? How many moles will I use? One mole?
*January 26, 2010*

**Chemistry**

An aqueous solution contains 2.0 % NaCl by mass. (1) Calculate the molality (NOT molarity!) of the solution. (2) Calculate the mole fraction of the solution. I know how to solve both but the problem is missing one other compound/element. I know that molality is moles per kg of...
*January 26, 2010*

**Chemistry**

1, 2, and 3 I have no answers. I've been staring at my monitor for 47 minutes now and I'm not coming up with any answer. As for no. 4, I think it's because water protects/shields the fruit. Actually, I think my answer for no. 3 is because steam has heat which is ...
*January 21, 2010*

**Chemistry**

4 super tough chemistry questions: 1.) Water has a considerably higher boiling point and lower vapor pressure than other molecules of similar or larger molar mass. For example, dinitrogen (N2), methane (CH4), etc. all have lower boiling points and higher vapor pressures than ...
*January 21, 2010*

**Chemistry**

I got lost. :( I got: a=390 ...and when I cubed that, I got a number that was too big so I figured that was wrong. What did I do wrong?
*January 17, 2010*

**Chemistry**

Palladium crystallizes with a face-centered cubic structure. It has a density of 12.0 g/cm^3, a radius of 138 pm, and a molar mass of 106.42 g/mol. Use these data to estimate Avogadro's number.
*January 17, 2010*

**Spanish**

Please check if the following conversation is correct: ¡Hola! ¿Como estas? Muy bien, ¿y tu? Fenomenal. ¿Qué hiciste el fin de semana pasado? Yo compré ropa nueva en la tienda el fin de semana pasado. ¿Qué compraste? Yo ...
*December 5, 2009*

**science**

Which structure is less likely to suffer damage during an earthquake: a high-rise, steel frame hotel built on sediments, or a wood frame house built on bedrock?
*November 29, 2009*

**Math**

1. Write a quadratic function in intercept form whose graph has the given x-intercepts and passes through the given point. x-intercepts: 2,3 point: (4,2) 2. Write a quadratic function in standard form whose graph passes through the given points. (1,-2),(-2,1),(3,6)
*November 24, 2009*

**Chemistry**

DrBob222, thank you so much for the very detailed information!
*November 24, 2009*

**Chemistry**

Regarding conductivity: 1. If a solution has a high conductivity, it indicates that there are a lot of __________________ in solution. [Answer: ions] 2. Pure acetic acid does not conduct electricity, nor does pure water, but a mixture of the two does conduct. This is explained...
*November 24, 2009*

**Math**

How would you solve this problem?: x2 + y2 = 25 x2 - y = 5 You have to solve for one variable either by substitution or elimination method and then use the answer to plug it in one of the equations to get the other variable. I've been at this problem for 30 minutes now and...
*November 22, 2009*

**Math**

Create a polynomial of degree 3 that has x-int at -1, 1, 3
*November 6, 2009*

**Chemistry**

Yup, as it turns out: cal = calorie Cal = big calorie / kilocalorie No wonder my answers were all wrong - I was converting to calorie instead of kcal! The correct answer was 4.57 Cal.
*October 30, 2009*

**Chemistry**

1.91x10^4 (or 19100) J is how many in Cal? I've tried these answers and they are all wrong: 4561.9 4.56x10^3 4562.0 4565 4569.4 4.57x10^3
*October 30, 2009*

**Chemistry**

Great! Thank you so much for all the help, DrBob222!
*October 29, 2009*

**Chemistry**

Eh, so what is the answer - Ga2O3 (basing it on the atomic mass of part (a))?
*October 29, 2009*

**Chemistry**

OK, so the formula is: (c) M2O3 ...and the identity and atomic mass of the metal M is: (d) Chromium which has a 51.9 amu Did I get the answers right?
*October 29, 2009*

**Chemistry**

Hi, DrBob222! Here's what I got for: (a) 69.44 g/mol (b) 46.4 g M/mol O I don't understand how to use those two information in order to determine the empirical formula (question (c)). I'm guessing it's some sort of ratio but I don't know how to use the ...
*October 29, 2009*

**Chemistry**

A particular metallic element, M, has a heat capacity of 0.36 J*g*K, and it forms an oxide that contains 2.90 grams of M per gram of oxygen. (a) Using the law of Dulong and Petit (Cp x M = 25 J*mol*K), estimate the molar mass of the metal M [Answer: _____ g/mol] (b) From the ...
*October 29, 2009*

**Math**

And what is the domain of gºf(x)?
*October 25, 2009*

**Math**

What is the domain of these two functions? (1) g(x) = square root of 3 (2) f(x) = |x|
*October 25, 2009*

**Chemistry**

Thank you, bobpursley! Got the answer - .653
*October 24, 2009*

**Chemistry**

A quantity of N2 occupies a volume of 1 L at 290 K and 1.5 atm. The gas expands to a volume of 2.7 L as the result of a change in both temperature and pressure. Find the density of the gas at these new conditions (in grams per liter).
*October 24, 2009*

**Chemistry**

A particular metallic element, M, has a heat capacity of 0.36 J*g*K, and it forms an oxide that contains 2.90 grams of M per gram of oxygen. (a) Using the law of Dulong and Petit (Cp x M = 25 J*mol*K), estimate the molar mass of the metal M [Answer: _____ g/mol] (b) From the ...
*October 22, 2009*

**Chemistry**

Hello, I finally got it after like an hour and a half of trying. Basically, it gave the pressure, volume, and temperature and was asking what the new pressure is after reducing the volume and increasing the temperature. So happy I finally got it. :)
*October 17, 2009*

**Chemistry**

How do I solve this problem - i37_tinypic_com/qqeo8w.jpg (replace the underscore with a dot) It gives the pressure, volume, and temperature and the only formula that has all those values is PV=nRT but I don't know where to get the number of moles since it doesn't give ...
*October 17, 2009*

**Math**

How do i find the domain and range of these functions? f(x)=x+1 f(x)=2/x f(x)=(x+1)/(2x-5) f(x)=sqrt(x+1) f(x)=sqrt(3x-9) f(x)=1/sqrt(x-5)
*October 2, 2009*

**Government**

What are 15 ways in which the US government helps us in our daily lives? Local, state, and federal?
*September 19, 2009*

**Chemistry**

Given the unbalanced equation shown: _Al+_CuSo4 -> _Al2(SO4)3+_Cu When the equation is balanced using the smallest whole-number coefficients, what is the coefficient of Al?
*April 13, 2009*

**Chemistry**

A dry mixture of kno3 and sand could be separated by 1. adding water to the mixture and filtering 2. adding water to the mixture and evaporating 3. heating the mixture to a high temperature 4. cooling the mixture to a low temperature
*April 13, 2009*

**Chemistry**

Fractional distillation is a technique used to separate complex mixtures of hydrocarbons based on differences in their 1. heats of fusion 2. heats of vaporization 3. melting points 4. boiling points
*April 13, 2009*

**Chemistry**

A sealed flask containing 1.0 mole of H2(g) and a sealed flask containing 2.0 moles of He(g) are at the same temperature. The two gases must have equal 1. masses 2. volumes 3. average kinetic energies 4. numbers of molecules
*April 12, 2009*

**Chemistry**

A sealed flask containing 1.0 mole of H2(g) and a sealed flask containing 2.0 moles of He(g) are at the same temperature. The two gases must have equal 1. masses 2. volumes 3. average kinetic energies 4. numbers of molecules
*April 12, 2009*

**Chemistry**

A sealed flask containing 1.0 mole of H (g) and a sealed flask containing 2.0 moles of He(g) are at the same. 2 temperature. The two gases must have equal 1. masses 2. volumes 3. average kinetic energies 4. numbers of molecules
*April 12, 2009*

**Chemistry**

Which temperature change would cause the volume of a sample of an ideal gas to double when the pressure of the sample remains the same? 1. from 200°C to 400°C 2. from 400°C to 200°C 3. from 200K to 400K 4. from 400K to 200K
*April 12, 2009*