Tuesday

April 28, 2015

April 28, 2015

Number of results: 27,590

**College Chemistry**

I DO NOT understand the following! Please HELP :) 1st Part Substances A, B, and C can all act as oxidizing agents. In solution, A is green, B is yellow, and C is red. In the reactions in which they participate, they are reduced to A-, B-, and C- ions, all of which are ...
*November 10, 2010 by Lisa*

**college stats **

help please!!! 1. The average number of bumped passengers per day on FliRite Airlines is 2.47 with a standard deviation of 1.75. For a random sample of 40 days, what is the chance the average number of bumped passengers in the sample is between 2 and 2.75? a. About 91% b. ...
*July 12, 2013 by penelope*

**statistics**

Suppose that large dogs weights are normally distributed with a mean of 100 pounds and a standard deviation of 10 pounds. If one of these dogs is picked random: a) what is the probability that the dog will weigh over 110 pounds? b) what is the probability that the dog will ...
*March 26, 2010 by Anonymous*

**Chemistry**

A solution contains 0.0653g of compound in 8.31g of ethanol. The molarity of the solution is 0.0368m. Calculate the molecular weight of the compound For Further Reading Chemisty - drbob222, Thursday, February 7, 2008 at 9:40pm The molarity of the solution can't be 0.0368 m. It...
*February 9, 2008 by Lauren*

**AP Chemistry**

1. Equilibrium 2SO3(g) <--> O2(g) + 2SO2(g) A 3.21g sample of sulfur trioxide is placed in a 2.25 L cylinder and allowed to reach equilibrium at a constant temperature of 500 , as shown in the above equation. Analysis shows 1.23 X 10^-2 mol of sulfur dioxide at ...
*April 10, 2007 by anonymous*

**chemistry**

I need assistance with this question please. "The equation of the line for a graph of voltage (Ecell) versus log[Cu2+] was y= -0.0166x - 0.0082. The voltage of a solution with an unknown [Cu2+] was measured against the same reference cell, under the same conditions; the ...
*March 15, 2011 by upthecreek*

**Kinematics**

A 55.0kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is .300. What horizontal force must be applied to the box for it to start sliding along the surface? Please write out the solution. I am getting an answer of 165N but...
*October 5, 2012 by Jaybird*

**chemistry**

Suppose you add 92 ml of dilute acid to 46 ml of water. Both the water and acid were at room temperature (22 C) before being mixed. The temperature of the solution increased to 39 C. How much energy (in kJ) was released by the dissolution of the acid if the specific heat ...
*January 31, 2015 by danny*

**Math-Stat Help **

In a random sample of 78 teenagers, 32 admit to texting while driving. Construct a 98% confidence interval for the percentage of teenager that text while driving. Start by showing that conditions for constructing a confidence interval are met. 1) Check conditions 2) confidence...
*April 11, 2013 by MELISSA *

**Statistics and Probability**

One six-sided fair die is rolled, and one two-sided fair coin is tossed. If the coin turns up heads, then the number of spots showing on the die is the value (score) for that trial. If the coin is tails then twice the number of spots showing on the die is the value (score) for...
*December 16, 2010 by Laura*

**chemistry**

An ideal liquid solution has two volatile components. In the vapor in equilibrium with the solution, the mole fractions of the components are (a) both 0.50; (b) equal, but not necessarily 0.50; (c) not very likely to be equal; (d) 1.00 for the solvent and 0.00 for the solute. ...
*February 20, 2010 by david*

**College Chemistry**

A student weighs out 0.568 g of KHP (molar mass=204g/mol) and titrates to the equivalence point with (36.78 cm cubed which is 3) of a stock NaOH solution. What is concentration of stock NaOH solution? KHP is an acid with one acidic proton. The word cubed is in word form ...
*October 22, 2010 by Elleni*

**Chemistry**

A certain headache relief tablet is composed of monoprotic acetylsalicylic acid(C9H8O4(s)) and an inert filler. A 4.00 g tablet was crushed and dissolved to make 40.0 mL of solution. The solution was then titrated with 0.900 mol/L NaOH(aq). The volume of NaOH(aq) needed to ...
*June 9, 2011 by Maya*

**Chemistry**

Predict the standard cell potential and calculate the standard reaction Gibbs free energy for galvanic cells having the following cell reactions: 2H2+O2=2H2O in acidic solution 2H2+O2=2H2O in basic solution I understand the idea behind the problem, but I am not sure how the ...
*March 10, 2014 by Anonymous*

**statistics**

Suppose only 75% of all drivers in a certain state regularly wear aseat belt. A random sample of 500 drivers is selected. What is theprobability that a). Between 360 and 400 (inclusive) of the drivers in the sampleregularly wear a seat belt? b). Fewer than 400 of those in the ...
*October 21, 2010 by Dre*

**chemistry**

A radioactive sample contains 3.25 1018 atoms of a nuclide that decays at a rate of 3.4 1013 disintegrations per 26 min. (a) What percentage of the nuclide will have decayed after 159 d? % (b) How many atoms of the nuclide will remain in the sample? atoms (c) What is the half-...
*April 16, 2010 by Trixie *

**chem**

how to find mass of aspirin if I used 0.2845g of the powder(crushed apririn) with 1mL of 6.0 mol/L of Nacl? Does the dilution(the above chemicals are diluted in a 500mL volumetric flask) matter ,and does adding the HCL/Fe^3+ stock solution in the end matter (1.00 mL of the the...
*April 23, 2015 by linda*

**Metals**

Transition metals (also called heavy metals) form insoluble compounds with hydroxide ions. Therefore, it is possible to extract heavy metal ions from water by raising the pH. The precipitation reaction between cadmium(II) and hydroxide is shown below. Cd2+(aq) + 2OH−(aq...
*April 19, 2015 by Chemistry*

**statistics**

You are a travel agent and wish to estimate, with 98% confidence, the proportion of vacationers who use an online service or the Internet to make travel reservations. Your estimate must be accurate within 4% of the population proportion. a) No preliminary estimate is available...
*April 6, 2011 by alex*

**Chem**

The space occupied by any sample of matter is called its __________. volume
*January 14, 2007 by Dennis*

**chemistry**

if a sample of cough syrup has the mass of 50.0g and a density of 0.950 what is the volume
*September 18, 2007 by Amy*

**LI**

Can some please show me sample essays from previous test and how they analyzed it.
*January 30, 2008 by lou*

**Chem**

How many moles of copper sulfate, CuSO4 are in a o.671 g sample? How do I start on this?
*March 3, 2008 by Mark*

**English**

funny survey sample please! with scoring and interpretation pls!
*June 19, 2008 by Grace*

**math**

List all possible events in the sample space with outcomes A, B, and C.
*August 26, 2008 by Jope*

**infants**

i need sample pamplet on great tips for parnets to read.
*October 13, 2008 by miesha*

**statistics**

How does the sample size differ between qualitative and quantitative methods? Why?
*October 20, 2008 by nicky*

**statistics**

2. How does the sample size differ between qualitative and quantitative methods? Why?
*October 22, 2008 by nicky*

**statistics**

If a sample of size 30 is selected, the value of A for the probability P(t greater or less A) = 0.01 is?
*August 1, 2009 by Lina*

**Algbera 1**

Need an sample of two step equation word problem.
*October 11, 2009 by alyssa*

**Chemistry**

a sample of C3H8O that contains 200 molecules contain how many atoms?
*November 1, 2009 by ashlee*

**chemistry**

Calculate the amount of heat (in calories) released when the 1.2 g sample was burned.
*November 23, 2009 by Joevonie*

**8th grade**

i need help with identify population sample and sampling method
*November 23, 2009 by chris*

**statistical applications**

when is random sampling not the best approach to sample selection?
*March 8, 2010 by anette*

**chemistry**

how many moles are in a 65L sample of chlorine gas at 10degrees Celcius?
*March 11, 2010 by molly*

**Advanced 6th grade Math**

What is the sample space of expiremental probibility
*April 12, 2010 by zoe*

**Gen chemistry**

What is the hydronium ion concentration of an acid rain sample that has a pH of 3.45?
*April 20, 2010 by asasa*

**chemistry**

When a 16.9-g sample of NaOH dissolves in 70.0 g of water in a calorimeter, the temperature rises from 22.4°C to 86.6°C.
*June 16, 2010 by kala*

**chem**

when K temperature increases, the average kinetic energy of the particles in a sample do?
*September 14, 2010 by montery*

**chemistry**

A 200 mL sample of 1.0 M nitric acid is added to 1.0 M water. What is the resulting pH?
*October 8, 2010 by Anonymous*

**chemistry**

At what temperature (oC) will a gas sample occupy 6.1 L if it originally occupies 17.8 L at 27.1oC?
*October 13, 2010 by kellie*

**chemistry**

If you were given 0.026 milligrams of the compound, what would the mass of C in the sample be?
*October 28, 2010 by Rebecca*

**chemistry**

How many grams of methane gas (CH4) are in a 15.8 liter sample at 1.2 atmospheres and 27°C
*October 31, 2010 by smith*

**College Chem**

How many moles of O atoms are there in a sample of 86g sucrose (C12H22O11)?
*January 30, 2011 by Nae*

**Probability **

Let A and B be events in a sample space S such that P(A) = 0.6, P(B) = 0.4, and P(A B) = 0.27. Find the probabilities below P(A|B)
*February 28, 2011 by Anonymous*

**statistics**

Find the mean, median, and mode for the following sample of scores: 8, 7, 8, 8, 4, 9, 10, 7, 8, 8, 9, 8
*June 22, 2011 by Liz *

**algebra**

Calculate the pH of a sample of acid rain that has the H30t concentration of 3.0x4-5m
*June 25, 2011 by Michelle*

**physics**

A piece of metal has a density of 0.20g/cm^3.what is the volume in cm^3 of a 1g sample of a substance?
*July 17, 2011 by Gift*

**Chemistry**

How many moles of ions are released when this sample dissolves in water? 26.4 g of Ba(OH)2·8H2O
*September 23, 2011 by Chase*

**chemistry**

34.42mL of 0.1013 M NaOH is used to titrate a 25.00 mL sample of H2SO
*October 2, 2011 by Anonymous*

**PHYSICAL SCIENCE**

density of a sample of zinc that has a mass of 48 kilograms and a volume of 7.5 mL.
*October 5, 2011 by JOCOBI*

**Chemistry**

At what temperature (oC) will a gas sample occupy 9.8 L if it originally occupies 14.2 L at 25.9oC?
*October 17, 2011 by Sven*

**intro chem**

which sample contians the greatest number of atoms. a)10.0g He b)25.0g Ne c)115g Xe
*November 30, 2011 by misty*

**Chemistry**

What is the density of a gasoline sample that has a volume of 13.3 mL abd a mass of 8.86 grams?
*February 6, 2012 by Lisa*

**chem**

what mass of nitrogen can be obtained from a 400.0g sample of potassium nitrate?
*March 12, 2012 by kalina*

**Child Development**

Arandomly selected sample of a population for study is one in which:
*August 8, 2012 by Sandra*

**chemistry**

The concentrations of Ca and Na in a sample of river water are 13.4 mg/kg and 5.2 mg/kg. Express the concentration in molality
*September 11, 2012 by Wiped Out*

**C H E M I S T R Y !**

A sample of rain in an area with severe air pollution has a pH OF 3.5. What is the pOH of this rainwater?
*March 4, 2013 by Lauren J.*

**chemistry**

how many atoms are present in a sample of water molecules with a mass of 1.800g
*April 13, 2013 by Anonymous*

**math **

Find the probability between 42 and 48 speeders in a random sample of 100
*May 2, 2013 by john jones*

**math**

Mark flips a coin twice. How many outcomes are in the sample space
*May 16, 2013 by brandon*

**math**

Mark flips a coin twice. How many outcomes are in the sample space?
*May 17, 2013 by tarvey*

**Chemistry**

What is the volume of a sample of helium that has a mass of 5.13x10^-3 and a density of 0.17847g/L
*May 31, 2013 by Addie*

**Chemistry**

What mass of AgI can be produced from a 0.512g sample that assays 20.1% ALI3?
*July 13, 2013 by xavier*

**Chemistry**

Calculate the number of phosphorus atoms in 17.0g sample of calcium phosphate
*September 29, 2013 by Madison*

**Chemistry**

How many years will it take for 88g tritium to decay to an 11g sample?
*October 6, 2013 by Michelle*

**Chemistry**

A sample of NH3 gas occupies 75.0 liters at STP. How many molecules is this?
*January 3, 2014 by Leena*

**statistics**

Population Mean: 170 STD: 62.3 Sample size 100 95% CI 99%CI
*February 10, 2014 by Anonymous*

**Chemistry**

A 26.0 g sample of ice at -17.0°C is mixed with 124.0 g of water at 81.0°C. What is the equilibrium temperature?ºC.
*April 3, 2014 by Eliza*

**Chemistry**

The temperature of a 2.25L sample of gas decreases from 45.0'C to 20.0'C. What is the new volume?
*May 17, 2014 by Han*

**chem**

If a radioactive sample has an activity of 8.33 Bq, how many disintegrations per second are occurring?
*September 19, 2014 by bekah*

**chemistry**

Calculate the number of moles of O atoms in a 2.5x10(-6)kg sample of C8H10N4O2
*September 20, 2014 by frank*

**Chem**

After 450 years how many grams of C-14 will remain from a 100.0 g sample
*September 21, 2014 by Anonymous*

**chemistry**

How many formula units would there be in a 54.3 gram sample of sodium nitrate
*November 13, 2014 by gbolahan*

**Chemistry **

What is the mass of a sample of (NH4)2SO4 that contains 8.01 x 10^24 atoms of oxygen
*November 22, 2014 by Queen *

**math**

what is the standard deviation for a sample of 2 month old babies height: 15,17,20,16,23,16,19
*December 14, 2014 by ang*

**Chemistry**

Calculate the mass of a 0.253-mL sample of a liquid with density 0.789 g/mL
*January 21, 2015 by Drea*

**Stats**

What is the best measure to describe the total variability in a population or sample?
*March 11, 2015 by Dany*

**Physcis 30**

Q1) If there are 100 radioactive atoms with a half-life of 30 seconds, how many radioactive atoms will remain after one half-life (30 seconds)? How many will remain after two half-lives (60 seconds)? Three half-lives? So basically, after 30 seconds it will be 50.After 60 sec. ...
*January 6, 2011 by Marium*

**CHEMISTRY**

Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br− and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ as ...
*November 27, 2012 by sabrina*

**chem**

Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br− and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ as ...
*November 28, 2012 by sabrina: This is how the question is written.*

**math-please check my answer!!**

5x-7y=-14 7y-5x=14 what is the solution of the system of equations? ANSWER IS B??? A) A point B)Infinitely many solutions C) no solution Is the system consistent ot inconsistent? ANSWER IS CONSISTENT Is the system dependent or independent? ANSWER IS DEPENDENT??? Are my answers...
*August 1, 2010 by Michelle*

**Chemistry**

A solution of acetic acid was prepared by mixing glacial acetic acid with water.The solution was 25% of acetic acid by volume.How much glacial axetic acid must be used to prepare 120 mL of desired volume?
*July 15, 2014 by Syam*

**General Chemistry**

Vinegar is a 5.0% solution by weight of acetic acid in water. Given that the pH for vinegar is 2.41 and that Ka= 1.8E-5 and the density s 1.00g/mL, what is the percent dissociation of acetic acid in vinegar? I know the % dissociation equals the amount which did dissociate 5.0%...
*February 27, 2008 by Matt*

**Solutions Chem**

7) You have a 2.5M solution of Silver Nitrate. It contains 450mL of solution. How many grams of silver would you be able to extract? Cu (s) + 2AgNO3 (aq) -> 2Ag (s) + Cu (NO3)2 (aq) I've gotten this much: M=mol/L 2.5=mol/.45 mol= 2.5*.45 mol=1.125 Silver Nitrate= (Ag=107.9...
*April 15, 2011 by Sarah*

**Chemistry**

Enough of a monoprotic acid is dissolved in water to produce a 0.0195 M solution. The pH of the resulting solution is 6.24. Calculate the Ka for the acid. Also, the answer is not 1.7 * 10 ^ -11 The response is: You treated the initial concentration as 0. In this case, the ...
*April 22, 2012 by chem1*

**Chemistry**

How would each of the folowing affect the accuracy of the calculated neutralizing power of the antacid (too high, too low, no effect)? Explain why. a) Titration flask was wet with distilled water b) The burette was initally not rinsed with 0.10M NaOH and some water was left in...
*March 16, 2010 by Anonymous*

**CHEMISTRY> HELP QUICK! pls**

what is the pH of a 2.62x10^-1 M NaNO2 solution? NB the pKa for HCN=9.212 12.13 13.42 1.87 8.29 0.58 and also; what is the pH of a 2.62x10^-1 M HCN solution. NB the pKa forn HCN is 9.212. 4.90 9.21 0.58 11.32 13.42
*June 1, 2010 by Lucinda*

**math**

Bottle A, containing 12L of 15% acid, is combined with bottle B, containing 3L of 25% acid. Bottle C is 26% acid. How much of each solution is neede to have 24L of a 20% acid solution?
*February 1, 2012 by Anonymous*

**Chemistry**

What is the % M/M concentration of 5.00 mL of methanol in 25 g solution of methanol in water? The density of methanol is 0.791 g/mL. The density of water is 1.000 g/mL. What is the % V/V concentration for the solution? Please show work.
*February 19, 2013 by Margaret*

**Biology **

You need to make 2.5L OF 3M H2SO4. H2SO4 comes as a stock solution in a concentration of 18M. How many ml of stock H2SO4 would you need to make the new solution?
*January 15, 2015 by Anonymous*

**statistics**

The 92 million Americans of age 50 and over control 50% of all discretionary income (AARP Bulletin, March 2008). AARP estimated that the average annual expenditure on restaurants and carry out food was $1873 for individuals in this age group. Suppose this estimate is based on ...
*September 26, 2014 by ashley*

**Chemistry**

Calculate the initial molarity of KNH2 and the molarities of K+, NH3, OH-, and H3O+ in an aqueous solution that contains 0.75 g of KNH2 in 0.255 L of solution. You may ignore the reaction of NH3 with water. I already found the initial molarity, but I am not sure how to find ...
*February 22, 2010 by Trixie *

**Chemistry**

20.2 mL of 0.234 M FeCl3 is added to 42.5 mL of 0.453 M NaOH. Iron(III) hydroxide precipitates. NaCl remains in aqueous solution. 1) What mass (in g) of Fe(OH)3 should precipitate (assuming 100% yield)? 2) How many moles of the excess reactant remain after the reaction is ...
*November 23, 2010 by Lilly*

**Chemistry**

A calorimeter contains 22.0 mL of water at 14.0 C. When 2.50 g of X (a substance with a molar mass of 66.0 g/mol) is added, it dissolves via the reaction X(s)+H_2O(l)--------> X(aq) and the temperature of the solution increases to 25.5 C. Calculate the enthalpy change, ...
*April 2, 2012 by Amanda*

**chemistry**

Consider a solution made by mixing 500.0 mL of 0.04182 M Na2HAsO4 with 500.0 mL of 0.03645 M NaOH. Complete the mass balance expressions below for Na and arsenate species in the final solution. There are 4 arsenate species, but I only got three of them. I am unsure of what the...
*March 23, 2013 by Jackie*

**Chemistry**

Predict the standard cell potential and calculate the standard reaction Gibbs free energy for galvanic cells having the following cell reactions: a.)3Zn + 2Bi3+ = 3Zn2+ + 2Bi b.)2H2 + O2 = 2H20 in acidic solution c.)2H2 + O2 = 2H20 in basic solution d.)3Au+ = 2Au + Au3+ I ...
*February 27, 2014 by Anonymous*

**chemistry**

a student dissolves 0.625 g of pure benzoic acid in distilled water and titrated the resulting solution to the equivalence point using 40.8 mL of the standardized NaOH solution from Part a, assuming that benzoic acid has only one ionizable hydrogen, answer the following: ...
*November 4, 2011 by Anonymous*

**Biochemistry**

1. MES (2-(N-Morpholino)ethanesulfonic acid) is a common buffer used in biochemistry labs to stabilize proteins. The pKa for MES is 6.09. a. What is the pH of 1 liter of a 200 mM MES aqueous solution? Clue: you will need to solve a quadratic equation. (2.5 points) b. How much...
*January 29, 2012 by Peter*

**CHM1045**

NH4NO3(s) right arrow NH4+(aq) + NO3−(aq) In order to measure the enthalpy change for this reaction, 1.21 g of NH4NO3 is dissolved in enough water to make 25.0 mL of solution. The initial temperature is 25.8°C and the final temperature (after the solid dissolves) is 22....
*March 30, 2013 by Philip Golden*