Thursday

April 24, 2014

April 24, 2014

Number of results: 15,408

**Chemistry**

1.) A 3.000gram sample of a hydrate compound containing Co, C2O4, and H2O was combusted to give 1.316g of Co3O4. What is the percentage of Cobalt in the oxide? 3.) 2.000 grams of a sample containing Co, C2O4, and H2O showed there to be 0.9621g of oxalate in the sample. Was is...
*Sunday, March 3, 2013 at 10:01pm by Robert*

**chemistry**

a 2.52-g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur was burned in excess O to yield 4.23 g of CO2 and 1.01 g of H2O as the only carbon and hydrogen containing products respectively. Another sample of the same compound, of mass 4.14 g, ...
*Saturday, February 15, 2014 at 9:24pm by Grace*

**Chem Quanti**

An organic pesticide (MW 183.7) is 8.43% Cl. A 0.627-g sample containing the pesticide plus inert material containing no chloride was decomposed with metallic sodium in alcohol. The liberated chloride ion was precipitated as AgCl weighing 0.0831 g. Calculate the percentage of ...
*Monday, January 16, 2012 at 5:50pm by Charmaine*

**Chemistry**

A sample of nitrogen containing 1.5x10^23 molecules has the same number of molecules as a sample containing A. 1.0 mole of H2 B. 2.0 moles of He C. 0.25 mole of O2 D. 0.50 mole of Ne
*Tuesday, March 12, 2013 at 8:47pm by Brandi*

**Chemistry**

A sample of nitrogen containing 1.5x10^23 molecules has the same number of molecules as a sample containing A. 1.0 mole of H2 B. 2.0 moles of He C. 0.25 mole of O2 D. 0.50 mole of Ne
*Tuesday, March 12, 2013 at 8:48pm by Brandi*

**Chemistry**

consider 2 sample of nitrogen gas. sample 1 contains 1.5 mol of N2 and has a volume of 36.7L at 25C and 1 atm. sample 2 has a volume of 16.5L at 25C and 1 atm. calculate the number of moles of N2 in sample 2 do i use the pv= nrt equation? and do i only use the information ...
*Tuesday, June 8, 2010 at 8:13pm by Anonymous*

**statistics**

Suppose that the percentage returns for a given year for all stocks listed on the new york stock exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n=5 stocks from the ...
*Monday, November 9, 2009 at 11:45am by ileana*

**Chemistryy.**

Some mole problems! Which quantity of neon may be represented by the symbol Ne? A) 1 gram B) 4 liters C) 6 x 1023 atoms D) 2 moles A sample of nitrogen containing 1.5 x 1023 molecules has the same number of molecules as a sample containing A) 1.0 mole of H2 B) 0.25 mole of O2 ...
*Monday, June 6, 2011 at 9:17pm by Jenny*

**Chemistry**

If I am given that an unknown sample containing iron(II)ion is .949 g and it requires 31.28 ml of .01192 M KMnO4 to titrate the sample to a pink end- point.... How can i calculate the moles of MnO4 ion consumed and the moles of of Fe^(2+) in the sample? Thanks
*Tuesday, January 13, 2009 at 9:29pm by Rosa*

**Statistics**

A lottery uses 4 urns containing chips 0 to 9. One chip is selected at random from each urn. How many sample points are in the sample space?
*Tuesday, May 22, 2012 at 12:34pm by Tammy*

**statistics**

A lottery uses 4 urns containing chips 0 to 9. One chip is selected at random from each urn. How many sample points are in the sample space?
*Saturday, January 18, 2014 at 11:24am by betty*

**Chemistry**

A 3.000gram sample of a hydrate compound containing Co, C2O4, and H2O was combusted to give 1.316g of Co3O4. What is the percentage of Cobalt in the original sample?
*Thursday, June 6, 2013 at 11:57am by Jessica*

**Chemistry**

A Student Performing a lab weighed a 1.0993g sample, containing an unknown KHP, which required 18.06mL of 0.1879M NAOH to reach the phenolphtalein endpoint. a) How many moles of base were consumed by the KHP in this sample? b) How many grams of KHP were titrated? c)What is the...
*Wednesday, May 9, 2012 at 9:37am by Brittany *

**chemistry**

Please help me through this problem... A 0.5117 gram fertilizer containing phsphorus was oven dried. The weight of the dried sample is 0.4998 grams. However, 10% moisture is still retained in the sample. Calculate the moisture content in the sample in as received and dry basis...
*Friday, August 31, 2007 at 12:24pm by smiley*

**maths probability**

Consider an experiment with four possible outcomes which we denote by Wi for i = 1,2,3,4. Sample space is Omega = {w1,w2,w3,w4}. Consider events A= {w1}, B = {w1,w2}, C = {w1,w2,w3} and D = {w2,w4}. Given that P(A) = 1/10, P(B) = 1/2, P(C) = 7/10, compute P(D)
*Thursday, November 28, 2013 at 7:12pm by Jessica*

**qnt/351**

Which of the following statements about the two sample sizes is NOT true? Assume thepopulation standard deviations are equal A. Sample A = 11; sample B = 13 B. Sample A = 12; sample B = 14 C. Sample A = 13; sample B = 13 D. Sample A = 10; sample B = 16
*Monday, March 31, 2014 at 2:10pm by arelis*

**statistics**

Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5 stocks from the ...
*Monday, August 31, 2009 at 6:58pm by Amy*

**Statistics**

Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5 stocks from the ...
*Monday, June 7, 2010 at 12:16am by Mary*

**Chemistry**

If I titrate a sample containing Ammonium Sulphide with a 0.05m Cadmium chloride until an end point is reached, how do I calculate the % sulphide in the sample
*Friday, February 8, 2013 at 5:22am by David*

**statistics**

Consider a random sample of 37 students, and consider the number who graduate in six years. . Find the probability that 20 students in the sample graduate in six years
*Tuesday, March 20, 2012 at 4:57pm by Jack*

**chemistry**

if a sample of alloy containing magnesium and metal that doesn't react wtih hydrochloric acid are reacted, how much heat would be evolved from a 5 gram sample that is 30% magnesium?
*Wednesday, July 13, 2011 at 7:11pm by mike*

**Higher Chem**

A 0.5537-g sample containing oxalic acid required 21.62 mL of 0.09377 M NaOH for titration. If the reaction is H2C2O4 + 2NaOH Na2C2O4 + 2H2O, calculate the % H2C2O4 in the sample.
*Monday, January 23, 2012 at 3:50pm by Polly*

**Chemistry**

a sample of limestone and other solid materials is heated and the limestone decomposes to give calcium oxide and carbon dioxide: CaCO3 ----> CaO + CO2 a 1.506 g sample of limestone containing material produces 284 mL of CO2 at STP. what is the mass percent os CaCO3 in the ...
*Thursday, April 28, 2011 at 9:34am by Ben*

**chemistry**

A 0.200g sample containing mn02 was dissolved and analyzed by addiction of 50ml of 0.100M fe to drive the reation. The excess fe required 15ml of 0.0200 m kmn04. Find % mn304 fw 228.8mg/mmol in the sample? who helps me
*Sunday, December 9, 2012 at 1:05am by Fai*

**chemistry**

A 1.252g sample containing iron is dissolved and converted to FE 2+ followed by addition of 25ml of 0.01M k2 cr2 07. The excess K2cr207 required 6.85 ml of 0.015M. Find the percentage FE304 FW 231g/mol in the sample. The right 7.96% Who helps me
*Sunday, December 16, 2012 at 4:33pm by Fai*

**statistics**

1. A random sample of n = 16 scores is selected from a normal distribution with a mean of µ = 50 and a standard deviation of á = 10. What is the probability that the sample mean will have a value between 45 and 55? What is the probability that the sample mean will have a value...
*Thursday, May 5, 2011 at 5:48pm by jansa*

**chemistry**

A 1.252g sample containing iron dissolved and converted to Fe followed by ADDITION OF 25ML OF 0..01m K2CR2 07. THE EXCESS K2CR207 REQUIRED 6.85ML OF 0.015m SN2+. Find the percentage fe3 04 fw 213g/mol in the sample. Who helps me
*Tuesday, December 11, 2012 at 11:27pm by Fai*

**Chemistry**

Consider titrating an unknown chloride sample with 0.10 +/- 0.01M AgNO3 and the following data: Initial Buret reading-0.19 +/- 0.02mL Final Buret reading- 9.26 +/- 0.03mL Unknown sample mass- 95.0 +/- 0.2mg Find the weight 5 of Cl- in the sample.
*Tuesday, February 12, 2013 at 7:28pm by Stephanie *

**chemistry**

Consider two glasses. Glass A has a composition of 100% SiO2. Glass B has a composition of 25% Na2O - 75% SiO2. (a) Which sample has a shorter average bond length (r)? (b)Which sample has a higher thermal expansion coefficient? (c) Which sample has a lower viscosity?
*Wednesday, April 10, 2013 at 8:33am by Anonymous *

**Chemistry**

Consider a solution containing 0.150 M Ba(OH)2. Calulate the pH.
*Sunday, March 11, 2012 at 6:53pm by Anonymous*

**College-Chemistry**

NaOH(s)+ H2SO4(aq)=Na2SO4(aq) + H2O(l) Consider the unbalanced equation above.A 0.900 g sample of impure NaOH was dissolved in water and required 37.0 mL of 0.145 M H2SO4 solution to react with the NaOH in the sample. What was the mass percent of NaOH in the sample?
*Friday, February 26, 2010 at 12:12pm by Tiffany*

**statistics**

A random sample of n= 16 scores is selected from a normal distribution with a mean of u=50 and a standard deviation of q=10. A. what is th probability that the sample mean will have a value between 45 and 55? B. What is the probability that a sample mean will have a value ...
*Wednesday, May 4, 2011 at 12:22pm by Zelinka*

**statistics**

27. Consider the following hypothesis test. H0: µ = 15 Ha: µ ≠ 15 A sample of 10 gives a sample mean of 8.9 and population variance of 9. Consider the following data drawn from a normally distributed population: 4, 8, 12, 11, 14, 6, 12, 8, 9, 5, α = 0.01 a) At α...
*Monday, August 8, 2011 at 11:16am by charlie*

**Redox Titration questions!**

Oh goodness, I'm such a pain! I need some help with these! How do I calculate the percentage? How do I start it? 2. Imagine that you ran a similar titration using a different iron sample with 0.02 M KMnO4 as the titrant. Calculate the percent of iron in the sample if the ...
*Wednesday, June 11, 2008 at 9:05pm by Angel*

**Chemistry**

A blood serum sample containing Na+ gave an emission signal of 4.27 mV. A small volume of concentrated standard Na+ was then added to increase the Na+ concentration by 0.102 M, without significantly diluting the sample. This "spiked" serum sample gave a signal of 8.09 mV. Find...
*Monday, December 12, 2011 at 10:52pm by Ken*

**Statistics**

Consider a population with mean = 43 and sd = 5.2. Calculate the x-score for an sample mean of 46.5 from a sample of size 35.
*Friday, March 18, 2011 at 2:57pm by Jamie*

**chemistry**

I am enrolled in analytical chemistry after a 4 year break from any chemistry. I was recently given a problem set and I need some help on the following: A 0.899g sample containing epsom salt, MgSO4 & 7 H2O, and other non-hydrated materials was dehydrated completely in a stream...
*Wednesday, January 30, 2008 at 5:35pm by Kenneth*

**chemistry**

last one, i PROMISE A compound containing only C, H, O and Cr was subjected to combustion analysis. A sample of 10.88 mg produced 22.43 mg of CO2 and 4.59 mg of H2O. The chromium in the sample was precipitated as 14.09 mg of Ag2CrO4. Determine the empirical formula of the ...
*Tuesday, November 6, 2007 at 8:46pm by confused student..*

**homework statistics**

Consider a random sample with sample mean x. If the sample size increased from n = 40 to n = 360, then the standard deviation of x will: a. remain the same b. increase by a factor of 9 (will be multiplied by 9) c. decrease by a factor of 9 (will be multiplied by 1/9) d. ...
*Friday, July 22, 2011 at 2:01am by Jackay 70*

**Physics - Heat and phase change **

Consider a 14.3 g sample of steam initially at 100*C. How many kilojoules equal the amount of energy emitted by this sample as it condenses, cools to it's freezing point, and subsequently freezes to form ice at 0*C
*Tuesday, March 19, 2013 at 7:55pm by Jos*

**math**

1. Consider the following scenario: A random sample obtained from a population has a mean of µ=100 and a standard deviation of σ = 20. The error between the sample mean and the population mean for a sample of n = 16 is 5 points and the error between a sample men and ...
*Monday, July 1, 2013 at 9:24am by susan*

**Chemistry**

A 2.52g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur was burned in excess O to yield 4.36g of CO2 and 0.892g of H20. Another sample of the same compound of mass 4.14g, yielded g of SO3. A third sample, of mass, 5.66g, yielded 2.80 g of ...
*Monday, September 6, 2010 at 7:30pm by Christina*

**Chemistry**

A 25.00 ml sample of a standard solution containing 1 g of CaCO3/L required 25.20 ml of EDTA to fully complex the Ca present. Calculate the volume of EDTA stoichiometrically equivalent to 1.0 mg of CaCO3. From the volume of EDTA required in titrating the sample, calculate the ...
*Sunday, March 14, 2010 at 11:32pm by Anonymous*

**chemistry**

Hey, I am having a real hard time getting the answers to the problems. Any help would be greatly aprreciated! 1. When 11 mL of a solution containing 2.9 M AlBr3 is diluted to 33 mL, a dilute solution is formed. What is the Br- concentration in 25 mL of the dilute solution? 2. ...
*Wednesday, November 7, 2007 at 5:35pm by chelsea*

**science**

Al(s) + HCl(aq) AlCl3(aq) + H2(g) Zn(s) + HCl(aq) ZnCl2(aq) + H2(g) Consider the unbalanced equations above. A 0.250 g sample of a mixture of aluminum and zinc metal is reacted with an excess of hydrochloric acid. Both metals react with hydrochloric acid. The sample produces ...
*Monday, April 29, 2013 at 5:20pm by samantha*

**Chemistry**

Al(s) + HCl(aq) AlCl3(aq) + H2(g) Zn(s) + HCl(aq) ZnCl2(aq) + H2(g) Consider the unbalanced equations above. A 0.200 g sample of a mixture of aluminum and zinc metal is reacted with an excess of hydrochloric acid. Both metals react with hydrochloric acid. The sample produces ...
*Monday, October 7, 2013 at 6:56pm by Connor*

**chemistry**

A 0.46771g sample containing sodium bicarbonate was titrated with hcl requiring 40.72ml. The acid was standardized by titrating 0.1876g requiring 37.86ml of the acid.Find the percentage of NAHCo3 FW 84mg/mmoml in the sample? Who helps me to solve it
*Thursday, November 22, 2012 at 1:10pm by Fai*

**math check**

Consider the following set of data. Pairs 1 2 3 4 5 Sample A 2 8 7 9 2 Sample B 7 8 1 1 8 Find the standard deviation sd of the paired differences. (Give your answer correct to two decimal places.) My answer was 5.00.
*Saturday, June 22, 2013 at 8:40am by Tommy8*

**chemistry**

0.550g sample containing only nacl and kbr.it dissolved in water and titrated with a 0.0322M solution of agno3. complete titration of both halides was found to require 30.45ml of agno3 solution. calculate the weight percent of cl in the solid sample.
*Friday, March 27, 2009 at 10:57pm by jacque*

**chemistry**

Suppose there are two known compunds containing the genetic elements X and Y. You have a 1.00-g sample of each compounds. One sample contains 0.33 g of X abd the other contains 0.42 g of X. Identify plausible sets of formulas for these two compounds.
*Sunday, September 15, 2013 at 7:06pm by london*

**statistics**

Consider a sample mean (xbar) of 46 caluclated from a sample of size 35 drawn from a population of over 1000. Would it be appropriate to use the standard score table to look up the probability of a z score calculated on these data? Why or why not?
*Friday, December 2, 2011 at 2:30am by Kim*

**chemestiry**

Al2(SO4)3(aq) + BaCl2(aq) BaSO4(s) + AlCl3(aq) Consider the unbalanced equation above. A 0.680 g sample of impure Al2(SO4)3 reacts with excess BaCl2. If the sample produces 0.530 g of BaSO4, what is the mass percent of Al2(SO4)3 in the sample?
*Wednesday, March 20, 2013 at 7:30pm by edi*

**chemestiry**

Al2(SO4)3(aq) + BaCl2(aq) BaSO4(s) + AlCl3(aq) Consider the unbalanced equation above. A 0.680 g sample of impure Al2(SO4)3 reacts with excess BaCl2. If the sample produces 0.530 g of BaSO4, what is the mass percent of Al2(SO4)3 in the sample?
*Wednesday, March 20, 2013 at 7:30pm by edi*

**chemestiry**

Al2(SO4)3(aq) + BaCl2(aq) BaSO4(s) + AlCl3(aq) Consider the unbalanced equation above. A 0.680 g sample of impure Al2(SO4)3 reacts with excess BaCl2. If the sample produces 0.530 g of BaSO4, what is the mass percent of Al2(SO4)3 in the sample?
*Wednesday, March 20, 2013 at 7:30pm by edi*

**Chemistry**

A solid sample containing a simple mixture of NaHSO3 and Na2SO3 was dissolved in distilled water and titrated with a standard HCl solution. 13.88 mL was required to reach the first stoichiometric point, and an additional 45.12 mL to reach the second. What was the mass ...
*Monday, December 6, 2010 at 7:07pm by Silver*

**chemistry**

How many moles are in a sample of cobalt containing 5.0x10^23 atoms?
*Thursday, October 21, 2010 at 4:38pm by Nathan*

**Physics**

Consider a radioactive sample with a half-life of one week. How much of the original sample will be left at the end of the second week? The third week? The fourth week?
*Thursday, August 29, 2013 at 2:13pm by Tracee*

**statistics**

In the U.S. 42% of the population has type A blood. Consider taking a sample size 4. Let y denote the number of persons in the sample with type A blood. a)Pr(y=O) b)Pr(y=1) C)Pr(y=2)
*Tuesday, February 5, 2008 at 7:32pm by alice*

**Chemistry**

Gravimetric analysis does not always involve a precipitate. Consider the following problem. A mixture of calcium carbonate and calium oxide has a mass of 8.35 grams. When heated strongly, the CaCO3 in the sample decomposes into solid CaO and carbon dioxide gas. The calcium ...
*Monday, December 6, 2010 at 11:27pm by Josh*

**Chemistry**

Gravimetric analysis does not always involve a precipitate. Consider the following problem. A mixture of calcium carbonate and calium oxide has a mass of 8.35 grams. When heated strongly, the CaCO3 in the sample decomposes into solid CaO and carbon dioxide gas. The calcium ...
*Tuesday, December 7, 2010 at 1:09pm by Josh*

**Chemistry**

Gravimetric analysis does not always involve a precipitate. Consider the following problem. A mixture of calcium carbonate and calium oxide has a mass of 8.35 grams. When heated strongly, the CaCO3 in the sample decomposes into solid CaO and carbon dioxide gas. The calcium ...
*Wednesday, December 8, 2010 at 11:14am by Josh*

**Chemistry**

Gravimetric analysis does not always involve a precipitate. Consider the following problem. A mixture of calcium carbonate and calium oxide has a mass of 8.35 grams. When heated strongly, the CaCO3 in the sample decomposes into solid CaO and carbon dioxide gas. The calcium ...
*Friday, December 10, 2010 at 2:19pm by Josh*

**Chemistry**

A 25.40 g sample of water containing tritium,(3/1)H , emits 1450 beta particles per second. Tritium is a weak beta emitter, with a half-life of 12.3 yr. What fraction of all the hydrogen in the water sample is tritium?
*Monday, February 13, 2012 at 4:35pm by Steven*

**statistics**

Consider an upper-tail test of hypothesis for the difference in two population means. The sample data from the first population is: n = 50, x-bar = 110, s = 10. The sample data from the second population is: n = 75, x-bar = unknown, s = 11. We conclude the alternative ...
*Sunday, November 17, 2013 at 11:01pm by zac*

**chemistry**

What is the concentration of a solution containing 25g of NaCl in a 250mL sample?"
*Monday, June 6, 2011 at 12:12am by Samantha*

**Science**

A chemist weighed out 5.16 g of a mixture containing unknown amunts of BaO(s) and CaO(s) and placed the sample in a 1.50-L flask containing CO2(g) at 30.0°C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, the pressure of CO2(g) remaining was 230...
*Monday, April 19, 2010 at 9:33pm by Genn*

**Science**

A chemist weighed out 5.16 g of a mixture containing unknown amunts of BaO(s) and CaO(s) and placed the sample in a 1.50-L flask containing CO2(g) at 30.0°C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, the pressure of CO2(g) remaining was 230...
*Monday, April 19, 2010 at 9:35pm by Genn*

**chemistry**

A chemist weighed out 5.31 g of a mixture containing unknown amounts of BaO(s) and CaO(s) and placed the sample in a 1.50 L flask containing CO2(g) at 30.0°C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, the pressure of CO2(g) remaining was 230...
*Saturday, November 6, 2010 at 10:50pm by Anonymous*

**Chemistry**

1. Consider the conductance meter and the titration method of determining the salt content of a brine sample. Discuss at least two advantages and two disadvantages of each method. 2. A corrosion technologist pipetted a 50.00 mL sample of an unknown brine and titrated it with ...
*Friday, July 1, 2011 at 3:12pm by Shannon*

**statistics**

consider a sample mean of xbar of 46 calculated from a sample of size 35 drawn from a population of over 1000. Would it be appropriate to use the standard score table to look up the probability of a z score calculated on these data? Why or why
*Tuesday, May 15, 2012 at 8:05pm by Yolanda*

**chemistry**

What is the molarity of the Cl- ion in the solution of a sample containing 0.187g Cl- dissolved in 50.0 ml water?
*Tuesday, October 23, 2007 at 10:13pm by mel*

**Physics**

100-g sample of substance is heated to 100˚C and placed into calorimeter cup containing 150 g of water at 25˚C. The sample raises the temperature of water to 32.1. What is the specific heat of the substance?
*Sunday, March 21, 2010 at 10:04pm by John*

**Chemistry Help(Calorimetry)**

I have a few questions to ask, since I was absent from school and I do not really understand the calorimetry problems. 1) 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. Calculate for Delta H for the ...
*Friday, April 9, 2010 at 1:37am by Bonn*

**analytical chemistry**

at elevated temperature, NaHCO3 (83.98g/mol) is converted quantitatively to Na2CO3 (105.98g/mol).Ignition of 0.3592g sample of an antacid tablet containing NaHCO3 and non volatile impurities yielded a residue weighing 0.2362g. Calculate the percent purity of the sample.
*Sunday, January 26, 2014 at 7:17am by Anonymous*

**Chem**

A sample containing 1.2x10^-2 mol HCl is completely neutralized by 100.0mL of Sr(OH)2 what is the [Sr(OH)2]?
*Wednesday, December 15, 2010 at 1:17am by Anonymous*

**science**

a 100.0 gram metal sample is heated to a temperature of 110 degrees celcius then placed into a calorimeter containing 100.0 r of pure water (at initial temperature of 23 degrees celcius). after the sample and water reach thermal equalibrium, their final temperature is 29 ...
*Tuesday, March 1, 2011 at 7:53pm by jason wolthen*

**Chemistry**

Consider a sample of helium and a sample of neon, both at 30ºC and 1.5atm. Both samples have a volume of 5.0 liters. Which statement concerning these samples is not true? a- each weighs the same amount b- each has the same # of atoms of gas c- the density of the neon is ...
*Friday, November 6, 2009 at 4:08pm by John S.*

**CHEMISTRY**

Suppose you had a detection device that could count every decay event from a radioactive sample of plutonium-239.052156 (t1/2 is 24,000 yr). How many counts per second would you obtain from a sample containing 0.126 g of plutonium-239? (The mass of Pu-239 is 239.052156 u. ...
*Wednesday, September 5, 2012 at 9:17pm by Maryanne*

**Statistic **

consider the population of all students at your school. A certain portion support mandatory national service following high school. Your friend randomly sampled 20 students from the school, and uses the sample proportion who support MNS to predict the population at the school...
*Tuesday, September 11, 2012 at 4:20pm by Anonymous*

**advanced algebra 2**

Find an equation for the line with the given properties: 1) Containing the points (1, 3) and (-1, 2) 2) Slope = -2/3; containing the point (1, -1) 3) X-intercept = 2; y-intercept = -1 4) Parallel to the line 2x – y = -2; containing the point (-1, 2) 5) Perpendicular to the ...
*Friday, August 10, 2012 at 1:50pm by kerry*

**chem quantity**

a sample of soil containing hydrated barium chloride potassium chloride plus inert material weighd 0.8076g. tha sample was then dissolvd in water n treated with silver nitrate.tha resulting precipitate was collectd n found to weigh 0.5846g. calculate tha percentage of precipitate
*Sunday, September 15, 2013 at 4:19am by shanice*

**AP Chemistry**

Consider a 50.4 g sample of H2O(g) at 115°C. What phase or phases are present when 156 kJ of energy is removed from this sample? Specific heat capacities: ice, 2.1 J/g·°C; liquid, 4.2 J/g·°C; steam, 2.0 J/g·°C, ÄHvap = 40.7 kJ/mol, ÄHfus = 6.02 kJ/mol. (Select all that apply...
*Friday, November 28, 2008 at 11:25pm by Robert*

**chemistry**

A sample containing 0.0500mol of Fe2(SO4)3 is dissolved in enough water to make 1.00L of solution. This solution contains hydrated SO4 2- and Fe(H2O)6 3+ ions. The latter behaves as an acid: Fe(H2O)6 3+ --> Fe(H2O)5OH 2+ + H+ a) Calculate the expected osmotic pressure of ...
*Wednesday, February 16, 2011 at 5:10pm by Chris*

**Math**

Can someone please explain this problem? Consider the experiments involving rolling a single die once. Give the probabilities of the events described. Suppose that an experiment has five separate mutually exclusive outcomes: A,B,C,D and E. If the sample space for the ...
*Wednesday, August 5, 2009 at 3:37pm by B.B.*

**college**

Request for sample letters containing bad news messages. Need a few realy quick
*Tuesday, March 24, 2009 at 7:53pm by Jason*

**ap chemistry**

18. Answer the following question that relate to the analysis of chemical compounds. (a) A compound containing the elements C, H, N, and O is analyzed. When a 1.2359g sample is burned in excess oxygen, 2.241g of CO2(g) is formed. The combustion analysis also showed that the ...
*Thursday, December 27, 2007 at 9:56pm by alk*

**Chemistry Math**

A 0.4671g sample containing sodium bicarbonate was titrated with HCL requiring 40.72ml. The acid was standardized by titrating 0.1876g of sodium carbonate FW 106mg/mmol requiring 37.86ml of the acid. Find the percentage of NAHO3 FW 84mg/mmol in the sample Who helps me to solve...
*Sunday, November 18, 2012 at 1:18pm by Fai*

**chemistry**

a sample containing 1.50 mol neon gas has a volume of 8.00L.what is the new volume of the gas in liters when the following changes occur in the quantity of the gas at constant pressure and temperature? a.a leak allows on-half of the neon atoms to escape. b. a sample of 25.0g ...
*Sunday, June 27, 2010 at 12:49am by Jetta*

**chemistry**

#2) Consider the preciditation reaction of a solution containing 3.50 grams of sodium phosphate mixed with a solution containing 6.40 grams of barium nitrate. How many grams of Barium phosphate can form? Ba(NO3 )2 + Na3 PO4 yields Ba3 (PO 4 )2 + NaNO3 #2b) If the actural yield...
*Thursday, January 29, 2009 at 7:41pm by lyne*

**Statistics**

Consider the hypothesis test given by Ho:u=530, H1:u does not equal 530. In a random sample of 85 subjects, the sample mean is found to be 522.3. Also, the population standard deviation is 29. Determine the P-value for this test. Is there sufficient evidence to justify the ...
*Friday, March 8, 2013 at 9:35pm by Sandy*

**physics**

liquid pressure is independent on the? a. shape of the containing vessel b. area of the bottom of the containing vessel c. both a and b and d d. height of the containing vessel
*Wednesday, February 29, 2012 at 6:08am by ricajane*

**Chemistry**

A 2.304 gram sample containing an unknown amount of arsenic trichloride and the rest inerts was dissolved into a NaHCO3 and HCl aqueous solution. To this solution was added 1.500 grams of KI and 50.00 mL of a 0.00912 M KIO3 solution. The excess I3– was titrated with 50.00 mL ...
*Tuesday, April 16, 2013 at 10:30pm by Jessica*

**chemistry**

A 1.147 gram sample containing an unknown amount of arsenic trichloride and the rest inerts was dissolved into a NaHCO3 and HCl aqueous solution. To this solution was added 1.690 grams of KI and 50.00 mL of a 0.00821 M KIO3 solution. The excess I3– was titrated with 50.00 mL ...
*Wednesday, April 17, 2013 at 11:31am by Lana*

**chemistry**

A 1.857 gram sample containing an unknown amount of arsenic trichloride and the rest inerts was dissolved into a NaHCO3 and HCl aqueous solution. To this solution was added 1.540 grams of KI and 50.00 mL of a 0.00912 M KIO3 solution. The excess I3– was titrated with 50.00 mL ...
*Thursday, May 2, 2013 at 11:44pm by Sparkle*

**Chem**

What weight of sample containing 8.00 % Fe3O4 must be taken to obtain a precipitate of Fe(OH)3 that, when ignited to Fe2O3, weighs 150 mg?
*Monday, January 16, 2012 at 5:51pm by Yuki*

**chemistry**

Ben has 1L of 0.1mol/dm3 solution of KI & wish to take a sample containing 8.3g of solute.What volume should he measure
*Saturday, February 18, 2012 at 5:30am by Luc*

**chemistry**

What is the solubility of CaF2 in a buffer solution containing .30 M HCHO2 and .20 M NaCHO2? (Consider the equation CaF2(s) + 2H+(aq)--> Ca2+(aq) + 2HF(aq) and solve the equilibrium problem)
*Wednesday, February 29, 2012 at 10:38pm by Anonymous*

**chemistry**

calculate the number of liters of liquid ethanol (density = 0.789g/ml) required to obtain a sample containing 1.00*10^25 C2H5OH molecules
*Sunday, February 28, 2010 at 8:22pm by stephen*

**Chemistry Problem!**

What weight of sample containing 8.00 % Fe3O4 must be taken to obtain a precipitate of Fe(OH)3 that, when ignited to Fe2O3, weighs 150 mg?
*Monday, January 16, 2012 at 5:48pm by Sarah*

**Chemistry**

Prior to their phaseout in the 1980s, chemicals containing lead were commonly added to gasoline as anti-knocking agents. A 3.279 g sample of one such additive containing only lead, carbon, and hydrogen was burned in an oxygen rich environment. The products of the combustion ...
*Monday, April 21, 2014 at 9:02pm by Annabelle*

Pages: **1** | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>