# Posts by David

Total # Posts: 2,252

**CHEMISTRY**

1.) A water sample is found to have 9.0 ppb of chloroform,CHCL3. How many grams of CHCL3 would be found in a glassful (250 ML) of this water?

*February 12, 2010*

**chemistry**

The second one is correct. Regarding the first one though, I calculated the grams to 6.8 g of C2H5OH. I don't quite understand the next step (regarding the density, etc)

*February 12, 2010*

**College Math : Linear Algebra**

Well I guess no one can help. :/ Oh well, I'll figure it out

*February 9, 2010*

**College Math : Linear Algebra**

Suppose A is a square matrix satisfying the equation A^3 - 2I = 0. Prove that A and (A - I) respectively are invertible. (the hint is to find an explicit equation for A^-1. To prove A is invertible, this is what I did although I don't that it's right: A^3 - 2I = 0 A(A^...

*February 9, 2010*

**long-term**

What other challenges do case workers face when working with placement of the elderly in long-term care facilities?

*February 9, 2010*

**calculus**

How large does N have to be in order to approximate the integral of cos(x^2) from 0 to 1, using the Midpoint Rule, with error at most 10^(-6)?

*February 5, 2010*

**algebra**

Find an equation of the porabola described. - Vertex(0,0);directrix x + 1 = 0

*February 4, 2010*

**programming**

I am working on a project called VB Auto Sales I am working in CH 2. I have just about completed the assignment but I am unable to group two separate sections. Assignment Modify the project from the Chapter 1 VB Auto Center case study, replacing the buttons with images in ...

*February 4, 2010*

**Visual Basic**

I should say I cannot get the special notices to work with the colors.

*February 4, 2010*

**Visual Basic**

I am working on a project called VB Auto Sales I am working in CH 2. I have just about completed the assignment but I am unable to group two separate sections. Assignment Modify the project from the Chapter 1 VB Auto Center case study, replacing the buttons with images in ...

*February 4, 2010*

**Chemistry (Grade 11)**

A radioactive sample of 141Cs has a half-life of 32.5 days. In a sample that contains 8.00*10^7 nuclei of 141Cs, how many beta particles per second will be emitted? A 19.8 B 1.7*10^6 C 71 076 D 1185 E 2.47*10^-7 The 141 supposed to be a superscript text, but firefox won't ...

*February 3, 2010*

**6th Grade Science : Newtons First Law of Motion**

Explain the idea of streamlining, as it applies to a skydiver.

*January 30, 2010*

**6th Grade Science : Newton's First Law of Motion**

Explain the idea of streamlining.\, as it applies to the skydiver. If you have the following textbook: Scott Foresman Science, 6th Grade good for you! Look on pages B102 - B105.

*January 29, 2010*

**6th Grade math**

Use prime factorization.

*January 28, 2010*

**6th Grade math**

The Odgen School marching band has 91 musicians. If there are 7 student musicians in each row, how many rows are there?

*January 28, 2010*

**Maths**

That would make more sense! Many thanks

*January 28, 2010*

**Maths**

Please could I have some guidance and advice on the following question? A multiple choice question has 4 options, A,B,C and D. The numbers of students choosing the options are in the ratio 3:1:2:14. I need to calculate the number of students choosing each option, (there are ...

*January 28, 2010*

**shapes**

if i had just a regular triangle and then it turned 90 degrees how would it look

*January 27, 2010*

**11th grade math**

secondary largest possible answre is Answer: x⋅(38-2⋅x)2 Answer: 8.06181572077

*January 21, 2010*

**11th grade math**

had this same probem for college pre-calculue couldn't solve B any other way but guess and check/logic x=4.5

*January 21, 2010*

**6th Grade Grammar**

Underline the form of to do or to have in the sentence. Today, many do their best to learn about Einstein's work. Also, what does the "to do" and the "to have" mean?

*January 20, 2010*

**HSM210**

Mrs Sue, Sorry to keep bothering you ! I have once more corrected the four answers . Do you mind checking them again. I so hate these assignments as I have such a hard time. Thank you so much for looking over my answers for me. 8. The victims’ rights movement developed ...

*January 19, 2010*

**math**

how do you solve for x using logs: [(a + b)^x]/b^x I am not sure of the steps to get there.

*January 19, 2010*

**HSM210**

Mrs Sue I corrected the answers that you said I had wrong in my assignment . Do you mind checking these for me again to see if I corrected them . Thank you so much for your help. 1. The Supreme Court has a greater obligation to protect the rights of victims than those of ...

*January 19, 2010*

**HSM210**

Mrs Sue do you mind checking my answers for me please? I have been working on this assignment for several days. The following activity helps you sharpen your skills in recognizing deceptive reasoning. The statements below are derived from the viewpoints in this chapter. Beside...

*January 19, 2010*

**Chemistry**

does postassium nitrate have a high or slow conductivity

*January 12, 2010*

**Chemistry**

sorry i mean which reactant

*January 12, 2010*

**Chemistry**

if 8.50grams CH4 reacts with 15.9grams of oxygen gass which of the prdocut is the excess and which is the limiting.

*January 12, 2010*

**Chemistry**

i got the mass of aluminum chloride to be 42.7

*January 12, 2010*

**Chemistry**

in 25grams of aluminium oxide reacts with 50grams aquoues hyrdogen chloride what is the mass of aluminum chloride produced?

*January 12, 2010*

**6th Grade Math**

Thanks!!!

*January 11, 2010*

**6th Grade Math**

Estimate a range for each sum. 3.89 + 42.71 + 12.32 I don't understand what to do for "estimating a range".

*January 11, 2010*

**earth science**

what are the landscape regions that the hudson river flows through

*January 7, 2010*

**chemistry**

how do you balance the equation __Al+__CuO=>__Al2O3+__Cu

*January 4, 2010*

**Business**

Mr Jones intends to retire in 20 years at the age of 65. As yet he has not provided for retirement income, and he wants to set up a periodic savings plan to do this. If he makes equal annual payments into savings account that pays 4% interest per year, how large must his ...

*December 23, 2009*

**ELLS**

Do you know anything about English Language Learners?

*December 23, 2009*

**6th grade Math**

thanks!

*December 15, 2009*

**6th grade Math**

The gas tank of your parents car holds 12.9 gallons of gas. Because their car averages 27.8 miles per gallon, how many times will they have to fillup the gas tank to drive to cincinnati and back? From Detroit, Michigan to Cincinnati, Ohio = 264.1 miles.

*December 15, 2009*

**Calculus**

a) prove that the function x^3 + 9x^2 +33x assumes the value -8 at least once b)using the mean value theorom or rolle's theorom - no other methods will be accepted - prove carefully that x^3 + 9x^2 + 33x takes on the value -8 at most once

*December 10, 2009*

**Math -- 6th Grade**

Thank you drwls!

*December 8, 2009*

**Math -- 6th Grade**

The sum of two decimal numbers is 5.3. Their difference is 1.7, and their product is 6.3. What are the two numbers? Does the product have anything to do with getting the answers?

*December 8, 2009*

**6th grade Math**

Thank you Bob!

*December 8, 2009*

**8th grade math**

55 mhp to 70 mhp

*November 27, 2009*

**Economics**

U.S. antitrust enforcement policies have focused on 1) Enforcing market codes of ethics 2) Preventing "golden parachutes" 3) preventing price fixing arrangements 4) forcing firms to produce output at the point where P=MC 5) breaking up any firm with more than 10 ...

*November 20, 2009*

**comm arts**

when do you use homophone besides or except? Ican attend the meeting if it is scheduled any day of the week ..... Friday. What shoul I use. except or besides? Thanks

*November 17, 2009*

**Algebra**

trnslate to na algebraic expression a number divided by 15

*November 11, 2009*

**math**

solv the inequality: 1. 7-3x [is less than or equal to] 22 ---> x [is greater than or equal to] -5 2. 4x-2/3 [is greater than or equal to] 1/3 ---> x [is greater than or equal to] 3/5 are these correct??

*November 4, 2009*

**chemistry**

Q1) 5 liters of Butane gas (C4H10) is reacted with plenty of oxygen at 27 oC and 1 atm to produce carbon dioxide and water vapor. Calculate the following: 1- The volume of CO2 produced at 1 atm and 400 oC. 2- The mass of H2O vapor produced. 3- The mol % of the products. Given...

*November 2, 2009*

**9th grade**

@bobpursley so you mean we have to do a factor tree for 1000 numbers?!

*November 1, 2009*

**math**

Find an angle between 0 and 2Ð that is coterminal with given angle. 1. -7Ð /3 2. 10 3. 51Ð /2

*October 26, 2009*

**math**

Find an angle between 0 degree and 360 degree that is coterminal with given angle. a. 361 degree b. -100 degree c. 1270 degree

*October 26, 2009*

**council**

what is a good speech of secretary and vice presidents: this is what secretary it does attend council meetings take pictures at school functions distribute and collect surveys at school funtions and from classrooms participate in council activities vice president attend ...

*October 21, 2009*

**math**

27 / (5+4) * 19 = 27 / (9) * 19=3*19=57. Mom is right.

*October 21, 2009*

**math**

it is: -y/x* (2x+y)/(2y+x) let me now if you need more details.

*October 21, 2009*

**Social Studies**

thank you!

*October 20, 2009*

**Social Studies**

Yes. Can anyone help me?!?!?!?!? Help!!!!!!!!!!!!!!

*October 20, 2009*

**Social Studies**

I did but i can not find anything.

*October 20, 2009*

**Social Studies**

I need help finding a current event. The topic is A Famous Person Who Has Done Some Type Of Charitable thing. The article can be anywhere from last thursday to today. Thank You!

*October 20, 2009*

**math115**

The electricity costs of a buisness increased from $15,000 in one year to $16,000 the next. To the nearest whole percent what was the rate of increase?=7% Write the following as a common fraction or mixed number write in lowest terms 5.035 = 5 7/200

*October 20, 2009*

**math115**

thank you

*October 20, 2009*

**math115**

Let me try it this way I am dividing 30/49 by 16/21 or 30/49 dividing by 16/21= 45/56

*October 20, 2009*

**math115**

divide 30/49 divide 16/21= 45/56 a triangle has a base 15ft and an altitude of 8ft find the area =60ft^2

*October 20, 2009*

**Physics**

You are correct. I had the EXACT same Physics problem and got them correct.

*October 17, 2009*

**Math**

find mean, median and is mean or median more useful representation 25,29,30,30,30,31,33,34,40,41,46,63 mean 36 median 32 more useful 32

*October 17, 2009*

**Math**

find median 4,5,6,8,11,17 answer 7 find mean and median 68,69,71,75,76,76,81,82,86,88,93,94,95,95,96 answer mean is 83 median is 82 ?

*October 17, 2009*

**Math**

evaluate |-24|-|-22| answer -2? -|-618|answer -618 3-|7-9|answer 5? ?

*October 17, 2009*

**Math**

determine max and min value 3,- 36/7,-1,-2/3,5/4,-5,26/9 answer max3 min-5 ? put in asending order -2/9,-1/9,3/7,5/9,1/8

*October 17, 2009*

**Math**

add -4/5+{-3/4} simple form 1 1/5

*October 16, 2009*

**math**

Two circles of radius 4 are tangent to the graph y^2=4x at the point (1,2). Find the equations of the two circles.

*October 14, 2009*

**math**

Find (f + g)x, (f-g)x, (fg)x, and (f/g)x and their domains. f(x)=¡î(9-x©÷),g(x)=¡î(x©÷-4)

*October 12, 2009*

**math**

Find (f + g)x, (f-g)x, (fg)x, and (f/g)x and their domains. f(x) = ¡î(9-x©÷), g(x) = ¡î(x©÷-4)

*October 11, 2009*

**Math**

How much space (in ft³ ) will be taken up by the 458 balloons.

*October 11, 2009*

**Math**

Height: The volume of a cone is 100 in³. Find a function that models the height h of the cone in terms of its radius r.

*October 9, 2009*

**Math**

Minimizing Sum: Find two positive numbers whose sum is 100 and the sum of whose squares is a minimum.

*October 9, 2009*

**Math**

Maximizing Area: Among all rectangles that have a perimeter of 20 ft, find the dimensions of the one with the largest area.

*October 9, 2009*

**math**

Height: The volume of a cone is 100 in^3. Find a function that models the height h of the cone in terms of its radius r.

*October 9, 2009*

**math**

A woman 5 ft tall is standing near a street lamp that is 12 ft tall. Find a function that models the length L of her shadow in terms of her distance d from the base of the lamp.

*October 9, 2009*

**geometry**

Find a function that models the area A of a circle in terms of its circumference C.

*October 8, 2009*

**math**

A young man spent 1/4 of his allowance on a movie. He spent 11/18 of the remainder on after-school snacks. Then from the money remaining, he spent $3.00 on a magazine, which left him 1/24 of his original allowance to put into savings. how much of his allowance did he save?

*October 7, 2009*

**math**

If you place one full container of flour on one pan of a balance scale and similar container 3/4 full and a 1/3-pound weight on the other pan, the pans balance. How much does the full container of flour weight?

*October 7, 2009*

**math**

An airline passenger feel asleep halfway to her destination. When she awoke, the distance remaining was half the distance traveled while she slept. How much of the entire trip was she asleep?

*October 7, 2009*

**math**

60 guest were present at dinner. Is this correct?

*October 7, 2009*

**math**

how many guests were present at a dinner if every two guest shared a bowl of rice, every three guests shared a bowl of broth, every four guests shared a bowl of fow, and 65 bowls were used together.

*October 7, 2009*

**5th grade**

I am a 3-digit number.My first digit is a square number.My last digit is 3* my second digit,which is my half my first digit.What am I.

*October 6, 2009*

**physics**

Calculate the terminal speed of a wooden sphere(density 0.830g/m^3) falling throught air if its radius is 8.00cm and its drag coefficient is 0.500? From what height would a freely falling object reach this speed in the absence of air resistance?

*October 1, 2009*

**accounting 201**

I am sorry I am tired and meant to write professional fees.

*September 30, 2009*

**accounting 201**

Oops I said I could not figure out capital, it was processional fees that I meant to list. Capital is clearly 30,000.

*September 30, 2009*

**accounting 201**

I am having trouble figuring out my accounts payable and capital. Any help on going about and solving this would be greatly appreciated. I have listed the data below... Travis Fortney, an architect, opened an office on April 1, 2010. During the month, he completed the ...

*September 30, 2009*

**Science**

A 6.0 volt battery is hooked up to a light bulb, whose resistance is 3.1 ohms. How many electrons would leave the battery per second? (Hint: 1 electron = 1.6E-19 C)

*September 28, 2009*

**physics**

After falling from rest at a height of 29.2 m, a 0.488 kg ball rebounds upward, reaching a height of 20.3 m. If the contact between ball and ground lasted 1.68 ms, what average force was exerted on the ball? I'm so confused on where to start. tyvm

*September 22, 2009*

**5th grade**

4+9,6+7,8+5

*September 21, 2009*

**SOCIAL STUDIES**

HOW DID THE ICE AGES INFLUENCE HUMAN MIGRATION

*September 17, 2009*

**Elasticity (Physics)**

A tunnel of length L=150m, height H=7.2m, and width w=5.8m (with a flat roof) is to be constructed at a distance d=60m beneath the ground. The tunnel roof is be entirely supported by square steel columns, each with a cross sectional area of 960 cm^2. The mass of 1.0 cm^3 of ...

*September 9, 2009*

**4th grade**

G d h fr hhj

*September 3, 2009*

**physics**

vcfcffgygyy

*September 2, 2009*

**Chemistry**

if pressure on a 2.50 ml gas sample were doubled from 0.500atm to 1.00 atm what would be gas volume at the new pressure?

*September 2, 2009*

**Statistics**

A study has shown that the thickness of sheet steel follows an approximately uniform distribution from 20 to 50mm. What is the probability that a sheet of steel chosen at random will be between 20 and 30mm?

*August 30, 2009*

**Math**

Thanks so much I understand now

*August 28, 2009*

**Economics**

Suppose that the governmental authorities wished to decrease use of a pesticide that is leaching into groundwater supplies in a watershed by 60% from current use levels. Discuss the advantages and/or disadvantages of distributing marketable pesticide permits to each farm ...

*July 24, 2009*