Friday

September 30, 2016
Total # Posts: 513

**Chemistry-dilutions**

I have a 2000ppm benzoic acid solution.I want to prepare a 20ppm benzoic acid solution.Is it better to 1) do serial dilutions i.e. from 2000 to 200 to 20ppm or 2) prepare 20ppm standard fresh when required( take 10ul of 2000ppm stock and top up to 1ml in a LC vial with 990ul ...

*September 11, 2010*

**Chemistry**

What is the difference between Residual Standard Deviation and Relative Standard Deviation?

*September 11, 2010*

**Chemistry**

What is the difference between Residual Standard Deviation and Relelative Standard Deviation?

*September 11, 2010*

**math**

simplify 3sqrt-1/8

*September 5, 2010*

**Chemistry**

I have a 2.5g sample in 12.5ml solution.I'm supposed to do a spike into this solution with the sample.If my standard concentration is 2000ppm, how much of this solution should I use such that I get 200ppm spike in sample?

*August 31, 2010*

**child growth development**

When the XY genetic code begins to assert itself, A. ovaries begin to differentiate. B. testes begin to differentiate C. estrogen begins to be produced. D. brain development begins to occur more rapidly. I think the answer is C

*June 9, 2010*

**child growth development**

Regarding babies who are low in birth weight but born at full term, which of the following statements is true? A. Expect to find lanugo. B. Expect to dectect vernix. C. Expect to find that the mother's parents were smokers. D. Expect the child to be referred to as "...

*June 9, 2010*

**chem**

an indicator HIn is blue and its anion In- is red, Ka of indicator is 0.0001 at what pH value will a solution containing HIn be blue?

*June 2, 2010*

**chem**

what is the pH for the solution made from 11.1 mL of 0.278M NaOH solution mixed with 70.2mL of 0.13M ammonium chloride solution? pKa for NH4+ is 9.241

*June 2, 2010*

**chem**

calculate the solubility of Ca(OH)2 in a 0.469M CaCl2 solution at 31 degrees C, Ksp of Ca(OH)2 is 4.96 X 10*-6

*June 2, 2010*

**PHYSICS**

A train starts from rest and accelerates uniformly, until it has traveled 3 km and acquired a velocity of 20 m/s The train then moves at a constant velocity of 20 for 400 s. The train then slows down uniformly at 0.065 m/s2 until it is brought to a halt. Calculate the total ...

*May 25, 2010*

**science**

what are surface waves?

*May 6, 2010*

**chemistry**

How would I determine when isomeric dimethylbenzene yields 1 ,2 or 3 mononitro derivatives when treate with HNO3/H2SO4 Thanks in advance

*April 29, 2010*

**chemistry**

What are the oxidation states of the metals in the following compunds: [Ni (pyr)4NH3Br]I and Mn(C2O4)3 Thanks :)

*April 23, 2010*

**social studies**

What is the difference between high and low pressure systems and what weather does each bring?

*April 19, 2010*

**algebra **

(6a^3bc^5)(-3a^4b^2c^3) simplify

*April 11, 2010*

**MATH**

Find the surface area of the 4 x 4 x 4 cm Prism shown. You may want to draw a net to help you. Remember to answer in the correct units of measure for area. (10 points) (Points :10) 96cm 48cm2 96cm2 3 2. [8.08] Find the surface area of the cylinder with radius, r = 3 m and ...

*March 9, 2010*

**math- alegbra**

simpilfy the expression: [4x7]4 four and severn are the exponents

*February 4, 2010*

**math- alegbra**

simpilfy the expression: [4x7]4 four and severn are the exponents

*February 4, 2010*

**economics**

what is the consumer surplus, producer surplus and deadweight loss if a monopolist has demand p=100-Q and Cost= 10Q Thanks xox

*February 3, 2010*

**Trig**

How would you find tan80 and tan55 as needed in this problem? Use identities to find each exact value. (tan80+tan55)/(1-tan80tan55)

*February 2, 2010*

**Geography**

How old is the grand union canal?

*February 2, 2010*

**math**

5.3

*February 2, 2010*

**Algebra.. please help**

Please help. I have been trying to figure this problem out for an hour now. Solve the following system of equations. X + 8y = 5 (1) x=8-8y (2)

*January 31, 2010*

**Algebra**

Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 40 miles per hour and train B is traveling at 60 miles per hour. Train A passes a station at 5:25 A.M. If train B passes the same station at 5:37 A.M, at what time will train B catch...

*January 30, 2010*

**Word Problem**

The function H described by H(x)= 2.75x + 71.48 can be used to predict theheight in centimeters, of a woman whose humerus(the bone from the elbow to the shoulder) is x cm long. Predict the height of a woman whose humerus is 35 cm long.

*January 28, 2010*

**Math**

Amy paid 72.34 for a pair of running shoes during a 20%- off sale. What was the regular price?

*January 27, 2010*

**British Literature**

Please check my answers #11: Coffeehouses were centers for (A) literary activity (B) political debates © entertainment (D) all of the above. #11: D #12: After viewing the London Fire on September 2, 1666, Samuel Pepys (A) mailed a letter to his father (B) left town (C) ...

*January 21, 2010*

**geometry**

90 you just double it

*January 17, 2010*

**Math **

Unable to derive any clues from the following. Please help! Our class planned a holiday party for disadvantaged kids.Some of us baked cookies for the party.On the day of the party,we found we could divide the cookies into packets of two, three, four, five, or six and have just...

*January 5, 2010*

**math**

Bob has 4 more dimes than nickels. He has 1.45 in all. How many nickels does he have? Please explain and show your work.

*January 4, 2010*

**English**

how do you write descriptive

*December 7, 2009*

**math**

what math property do I choose to get 43+[35+57]

*November 16, 2009*

**Physics**

In order to determine the coefficients of friction between rubber and various surfaces, a student uses a rubber eraser and an incline. In one experiment, the eraser begins to slip down the incline when the angle of inclination is 36.4° and then moves down the incline with ...

*November 3, 2009*

**Physics!**

Two identical isolated particles, each of mass 1.55 kg, are separated by a distance of 30.6 cm. What is the magnitude of the gravitational force exerted by one particle on the other? --------------- I solved it as: Fg = G(m^2/r2) = G(m/r)2 = 6.673x10^−11 Nm2/kg2 (1.55 kg...

*October 31, 2009*

**Earth Science**

68.88888889 miles

*October 18, 2009*

**Physics**

A playground is on the flat roof of a city school, 7.00 m above the street below. The vertical wall of the building is 8.00 m high, forming a 1.00 m high railing around the playground. A ball has fallen to the street below, and a passerby returns it by launching it at an angle...

*October 15, 2009*

**Physics**

The water in a river flows uniformly at a constant speed of 2.53 m/s between parallel banks 69.8 m apart. You are to deliver a package directly across the river, but you can swim only at 1.74 m/s. (a) If you choose to minimize the time you spend in the water, in what direction...

*October 15, 2009*

**Physics**

A hare and a tortoise compete in a race over a course 1.20 km long. The tortoise crawls straight and steadily at its maximum speed of 0.540 m/s toward the finish line. The hare runs at its maximum speed of 9.00 m/s toward the goal for 0.800 km and then stops to taunt the ...

*October 9, 2009*

**Science**

It is 68.88888889 because there are ONLY 90 degrees of latitude between each pole. So, 6200/90=68.8888889.

*October 6, 2009*

**science**

hi could you please give me some idea's on how to make a 10 second timer without useing marbles,sand or electronics. thanks

*September 21, 2009*

**Economics**

Consider a country that initially consumes 100 pairs of shoes per hour, all of which are imported. The price of shoes is $40 per pair before a ban on importing them is imposed. Use a graph to explain what happens to the price of shoes and the quantity of shoes consumed after a...

*September 9, 2009*

**Economics**

Using demand and supply analysis, answer the following questions. What are the effects on the exchange rate between the British pound and the Japanese yen from: a. An increase in Japanese interest rates b. An increase in the price of British goods c. An increase in British ...

*September 9, 2009*

**math**

it is less than 60 and greater than55 if you add digits the sum is 13. write the number

*August 12, 2009*

**7th grade science**

what is a cell wall

*April 28, 2009*

**Organisational Behaviour**

What is Symbolic Protest in Illegitimate Polics terms?I ask my lecturer and he says where people from the same department come together and say that they don't want to work.Is it correct?

*March 18, 2009*

**6th grade**

What is the current world population of clownfish?

*February 14, 2009*

**history**

i don't know

*January 29, 2009*

**Physics**

You toss a ball up at 7.3m/s leaving your hand at 1.5 m above the floor. What is the balls velocity just before it hits the floor. Is the answer 2.7 m/s Suppose a second ball is tossed straight down at 7.3 m/s (from the same place 1.5 m above the floor). What would its ...

*January 14, 2009*

**Physics**

A train travels 84 km/h when it reaches a slower train 47 meters ahead traveling the same direction at 24 km/h. If the faster train decelerates at 2.1 m/s^2 while the slower train is at a constant speed, when will they collide? If the train that is faster begins to decelerate ...

*January 12, 2009*

**Physics**

Just before landing on mars, a spaceshuttle turns on its retroengine and eventually comes to a complete stop 15 meters above the planets surface. It then drops freely down to the surface. How long does it take to fall to the surface.What is the impact speed? Is the answer 1.5 ...

*January 11, 2009*

**Physics**

A train travels 84 km/h when it reaches a slower train 47 meters ahead traveling the same direction at 24 km/h. If the faster train decelerates at 2.1 m/s^2 while the slower train is at a constant speed, when will they collide? If the train that is faster begins to decelerate ...

*January 11, 2009*

**Physics**

A train travels 84 km/h when it reaches a slower train 47 meters ahead traveling the same direction at 24 km/h. If the faster train decelerates at 2.1 m/s^2 while the slower train is at a constant speed, when will they collide? If the train that is faster begins to decelerate ...

*January 11, 2009*

**Physics**

Just before landing on mars, a spaceshuttle turns on its retroengine and eventually comes to a complete stop 15 meters above the planets surface. It then drops freely down to the surface. How long does it take to fall to the surface.What is the impact speed? Is the answer 1.5 ...

*January 11, 2009*

**Math**

$432....i think u do 16*3*3*3..i think

*January 7, 2009*

**Human Resources**

Can someone tell me what is employee training and employee development?

*January 5, 2009*

**Chemistry**

Thank you for your help!

*December 29, 2008*

**Chemistry**

What is the shape and structure of Magnesium Oxide? Thank you for helping me.

*December 29, 2008*

**music**

what does 7:LAL mean its one of thoses things were you have to find what it means?

*November 14, 2008*

**chemistry**

The scales of a balance are 70, 3 and 0.9 which is between 0.011 and 0.012 .

*November 1, 2008*

**Chemistry**

Thank you DrBob222. Those were very helpful.

*October 21, 2008*

**Chemistry**

Can someone please tell me what four radioisotopes are used in medical diagnosis or treatment, and what their nuclear symbols are? Thanks

*October 21, 2008*

**Chemistry**

Thank you so much DrBob222. This was very helpful.

*October 21, 2008*

**Chemistry**

Can someone please tell me what four radioisotopes are used in medical diagnosis or treatment, and what their nuclear symbols are? Thanks.

*October 21, 2008*

**AP U.S History**

Thank you.

*October 18, 2008*

**AP U.S History**

Can someone please explain what Federalism is? I don't quite get it yet. Please be specific.

*October 18, 2008*

**Spanish**

Thank you so much. This really helped!

*October 16, 2008*

**Spanish**

I'm required to look up an article in a Spanish magazine that has to do with events that took place in Spanish hometowns. The magazine has to be in Spanish and it has to deal with event(s) that occurred in a Spanish hometown. I've looked everywhere on Google and can&#...

*October 16, 2008*

**HHHHEEELLLPPP**

Consider the brackets around the absolute value as a wall- you cannot break into that wall until you've gotten rid of everything around it: 8-|3x-2|=3 -8 -8 -|3x-2|= -5 multiply by that -1 in front of the absolute value to get |3x-2|=5 Now you can solve. When an absolute ...

*October 16, 2008*

**History**

Thank you very much!

*October 16, 2008*

**History**

In Article 2 of the U.S Constitution, what is the process for choosing the president? I'm required to explain the process in 4 steps.

*October 16, 2008*

**Chemistry**

I understand now. Thank you.

*October 16, 2008*

**Chemistry**

I'm a bit confused as to when I should use an alpha particle and when to use a beta particle in a nuclear equation. For instance, the nuclear equation for carbon-14 is nitrogen-14 and a beta particle. Could I also say the equation is Berylium-13 and an alpha particle since...

*October 16, 2008*

**math**

No, any whole number ending in 8 will never be prime. A number ending in 8 will always be divisible by 2. The rule for 2 is: If any number ends in any even number (0, 2, 4, 6, or 8) it will always be divisible by 2 and therefore it is not prime. There are other rules such as ...

*October 16, 2008*

**Chemistry**

Thank you so much!

*October 14, 2008*

**Chemistry**

Is it red?

*October 14, 2008*

**Chemistry**

If a hydrate of the formula MCl * xH2O decomposes when heated to produce HCL, what change would you expect to occur when a piece of litmus paper is held in the path of the vapor released?

*October 14, 2008*

**Chemistry**

Thank you so much. I really appreciate it!

*October 13, 2008*

**Chemistry**

What is the difference between percent abundance and relative abundance?

*October 13, 2008*

**french**

How do you ask if something is mild or spicy in French? What about asking to make meat well done? If you are out shopping, how would a cashier tell you that you gave too much or too little money?

*June 17, 2008*

**chemistry**

Thank you for your help! :D

*April 6, 2008*

**chemistry**

There are four main methods of making salts: Acid + Metal, Acid + insoluble base, Acid + alkali and solution of salt A + solution of salt B. a. a student wanted to make some sodium sulfate. i. which method would be best to use? ii. why? iii. which reactants would you use? iv. ...

*April 6, 2008*

**Marketing**

Hello, My group has been assigned to do a General Market Survey on a foreign country (we picked France). Can anyone give us some pointers on what topics/statistics to include, where to find information, anything at all? We are to use secondary data to compose a general ...

*March 26, 2008*

**math**

6xsquared +7x-3

*March 23, 2008*

**economics**

Suppose that you had $100. ABC bank is offering 5 percent simple interest. DEF Bank is offering 10 percent simple interest. Which bank would you deposit your money into if you wanted to earn more interest?

*March 16, 2008*

**Physics**

A closely wound rectangular coil of 80 turns has dimensions of 25 cm by 40 cm. The plane of the coil is rotated from a position where it makes an angle of 37 degrees with a magnetic field of 1.10 T to a position perpendicular to the field. The rotation takes .06 s. What is ...

*March 3, 2008*

**ALGEBRA**

THE PRICE OF A SWEATER IS $5 LESS THAN TWICE THE PRICE OF A SHIRT. IF FOUR SWEATERS AND THREE SHIRTS COST $200, FIND THE PRICE OF EACH SHIRT AND EACH SWEATER? HOW DO YOU SET UP THIS PROBLEM?

*February 11, 2008*

**MATH**

HOW DO YOU SOLVE 5Y=8-3X? (BIG HELP)

*February 11, 2008*

**MATH**

THE DIFFERENCE BETWEEN TWO NUMBERS IS 16. FIVE TIMES THE SMALLER IS THE SAME AS 8 LESS THAN THREE TIMES THE LARGER. FIND THE NUMBERS? HOW DO YOU SOLVE THIS? PLEASE.

*February 11, 2008*

**Eco**

jasmine works in sales but is considering quitting work for 2 years to earn an MBA. Her currrent job pays $40,000 peryear (after tax),but she could earn $55000 per year if she had her master of business admin. Tuition fees is $10000 per year. Jasmine's discount rate is 6% ...

*October 5, 2007*

**home ecinomics**

what is a carbohydrate

*September 25, 2007*

**Algebra 1**

Would this be correct? x(2x^2-100)

*August 29, 2007*

**Algebra 1**

I really need help! Plese!! The price of an item is given by p=2x^2-100. Find the polynomial that represents the revenue generated from the sale of x items.

*August 29, 2007*

**Honors English**

I'm doing a project on greek gods and I can'ty find any pictures on apollo.Please help. Hmmm. Did they have kodak cameras in mythology? Here is what Michangelo perceived he saw: (Broken Link Removed) Here are some other "pictures": (Broken Link Removed) Hmmm...

*August 6, 2007*

**chemistry**

The pKb of pyridine is 8.75. What is the pH of a 0.480M solution of pyridine?

*August 5, 2007*

**Econ**

Suppose that a borrower and a lender agree on the nominal interest rate to be paid on a loan. Then inflation turns out to be higher than they both expected. Does the lender gain or lose from this unexpectedly high inflation? Does the borrower gain or lose? Think it through. ...

*July 28, 2007*

**science**

what is the big idea of energy? The big idea for me is that mass and energy is one in the same, that each can be converted to the other. For some others, the big idea is that Entropy is created from useful energy, and in natural processes, that energy cannot be reclaimed.

*May 25, 2007*

**algebra**

sorry can't help you lol im so sorry but I just wanted to type on this about 4 years later hahahahah hope you did well though.

*March 11, 2007*

**English :Journal entry**

i have been asigned to write journal entery and i havent been doing it then our teacher told us that it is our assesment and i havnet done one sonce march and im panicking cause im not very good at english. can anybody help me?

*November 18, 2006*

**science**

im doing this for ma lil sis and even i dnt knw lol fanx for everyone tht has help also wen the candle is aloght it realeases both heat and light energy into the atmosphere around it

*October 21, 2006*