Monday

July 28, 2014

July 28, 2014

Number of results: 24,916

**Calculus**

Poli 761 (a fictitious substance) decays by about 7% every day. How much of a 88 pound sample remains after 9 days?
*May 6, 2014 by Ann*

**chem**

A sample of carbon dioxide with a mass of 0.91 g was placed in a 335 mL container at 363 K. What is the pressure exerted by the gas? Answer in units of atm
*May 30, 2014 by reis*

**chemistry**

Consider the equation 2kclo3(s) -> 2kcl(s)-1302(g). 3.00-g sample kclo2 is decomposed and the oxygen at 24.0 and 0.982 its either, 911, 304, or 608
*June 10, 2014 by kaitlin*

**statistics**

The following random sample was collected: 22 33 44 6. The 80% confidence interval for the mean is? I have the answers; however, I do not know how to plug in the numbers to solve the problem.
*June 21, 2014 by Nicole*

**chem**

1.) When determining the melting point it's described in my text as recording 2 points in the melting process. a) when the first drop of liquid is seen b) when all of the compound is liquified and since I have to determine the melting point of sulfanilamide pure and impure (I ...
*September 3, 2007 by ~christina~*

**Science**

Hello, I am working on Methylene Blue dye adsorption for my thesis. I am embarassed to say I don't know basic chemistry. Anyway, my question is I have Methylene Blue Trihyrate 95%. I am trying to prepare stock solution. If I plan to make 1000 mg/l of solution, Is it as simple ...
*November 19, 2007 by Sinduri*

**Statistics **

Prospective Cohort Study The following tables show the crude and sex-specific results from a Prospective Cohort Study that examines the association between a binary exposure (E) and the development of a disease (D) during 20 years of follow-up. Use these data to solve the ...
*January 15, 2013 by netspirit*

**Science**

If I want to make a solution that has a 5% concentration of salt, is it correct for me to have 380mL water and 20g salt? My method behind this was that I wanted a 400g solution, and so since 1mL water is equal to 1g water, I did: 400x0.95=380g water or 380mL water and 400x0.05...
*February 6, 2011 by Anonymous*

**Inorganic Chemistry**

Which aqeuous solution has a freezing point closest to that of 0.30M C12H22O11? A) 0.075M AlCl3 B) 0.15M CuCl2 C) 0.30M NaCl D) 0.60M C6H12O6 I know the answer but I don't know the reason or rationale behind it. Please explain. I suggest you review Raoult's Law at http://...
*August 5, 2007 by Vic*

**Chemistry**

To a beaker containing 200 mL of a solution of CuSO4 was added 10.0g of magnesium metal. When the reaction was complete, a mixture of Mg and Cu having a mass of 14.50g remained in the beaker. Calculate the molarity of the original CuSO4 solution. I understand that I need to ...
*February 17, 2012 by Kay*

**Math**

5).Hat size are determined by the measuring the circumference of the head in either inches or centimeters. Use ratio and proportion to complete the following table. Hat size Head circumference Head Circumference 7 ½ to nearest 1/5 inch to the nearest centimeter 7 3/8 23 3/5 60...
*May 28, 2010 by Mickey*

**chemistry**

the experiment is a sequence of Chemical Reactions. Procedure part A preparation fo copper (II) Hydroxide-get a solution of copper(II)nitrate. measure 25ml of solution. to blue solution add 2mL of concertarted NaOH while stirring. Let mixture settle and use litmus paper to ...
*September 15, 2010 by Missy *

**Chemistry**

Complete the following table for aqueous solutions of caffeine, C8H10O2N4. a) molality b) mass percent solvent c) Ppm solute All we're given is Mole fraction solvent= .900. How do I solve for the other parts with only this?? It XH2O = 0.9, then Xcaffeine=0.1. Suppose we have 0...
*March 20, 2007 by Chris*

**confused**

as i earlier posted and , 1 day ago , i am confusesd hw we ll find freezing point......isnt it T pure solvent - T solution .. which ll be 0-(-23.3) = 23.3 plz conform .. and do we have to use Kf.m .. formula in order to get ( -23.3)(1)= -23.3 .. as someone earlier posted plz ...
*January 25, 2009 by Dr Bob plz conform*

**chemistry**

Two new metallic elements have been discovered, Cimium (Ci) and Sadowium (Sd). Both the pure elements and their solutions form simple cubic lattices. The bond strengths of the Ci-Ci and Sd-Sd bonds are known, but not the Ci-Sd bond. Bond Bond Energy (kJ/mole) Ci-Ci -245 Sd-Sd...
*November 12, 2013 by Harold*

**Chemistry**

Two new metallic elements have been discovered, Cimium (Ci) and Sadowium (Sd). Both the pure elements and their solutions form simple cubic lattices. The bond strengths of the Ci-Ci and Sd-Sd bonds are known, but not the Ci-Sd bond. Bond Bond Energy (kJ/mole) Ci-Ci -245 Sd-Sd...
*November 15, 2013 by HelpMePLSSS*

**Chemistry**

Two new metallic elements have been discovered, Cimium (Ci) and Sadowium (Sd). Both the pure elements and their solutions form simple cubic lattices. The bond strengths of the Ci-Ci and Sd-Sd bonds are known, but not the Ci-Sd bond. Bond Bond Energy (kJ/mole) Ci-Ci -245 Sd-Sd...
*November 16, 2013 by youlifex*

**Chemistry**

Please show work. 2Al(s) + 2NaOH(aq) + 6H2O(l) ---> 2NaAl(OH)4(aq) + 3H2(g) What mass of hydrogen gas would be formed from a reaction of 2.48 g Al and 4.76 g NaOH in water? Pb(NO3)2(s) + 2NaI(aq) ----> 2PbI2(s) +2NaNo3(aq) (a) If the solution contains 7.00 g NaI, what ...
*February 25, 2013 by Anonymous*

**Chem**

A student was performing an extraction procedure of o-Xylene from water into octanol. The total mass of o-Xylene was 0.10 gram (molecular weight 106.2 g/mole). The volume of water was 990mL and volume of octanol 10 mL. There is a head space of 200 mL above the solution and it ...
*July 31, 2013 by Sahara*

**chemistry**

calcium nitrate + sulfuric acid =caso4+? write a balanced chemical equation for this reaction including states. Ca(NO3)2 + H2SO4 ==> CaSO4 + 2HNO3 You don't have enough information to provide states. CaSO4 will be a solid so you write CaSO4(s). H2SO4 will be (l) if it is ...
*July 30, 2007 by walter*

**Differential Equations**

a) Sketch the phase line for the differential equation dy/dt=1/((y-2)(y+1)) and discuss the behavior of the solution with initial condition y(0)=1/2 b) Apply analytic techniques to the initial-value problem dy/dt=1/((y-2)(y+1))), y(0)=1/2 and compare your results with your ...
*February 3, 2013 by Erica*

**Math**

-x^3 + 1.85x^2 - x +0.15 = 0 how can you solve for x? An exact solution or a numerical solution? Exact solutions can be obtained as follows: x^3 - 1.85x^2 + x - 0.15 = 0 First get rid of the quadratic term by substituting: x = (y + 1.85/3) You then obtain an equation of the ...
*July 10, 2007 by JV*

**Chemistry**

1) it is found that .30 M solutions of the three shots Na3X, Na2Y and NaZ have pH's of 8.5, 7.0 and 10.5 not necessarily in order. (X,Y, and Z AE anions. Na is sodium ion) A) explain how anions can act as bases in aqueous solution. Write a chemical equation to explain your ...
*April 6, 2014 by Reggie*

**Biochemistry**

Urea is heated in a test tube. A condensation reaction occurs. Which one? What is the formula for this reaction? Then cupper sulphate and sodium hydroxide is added to the tube. This is compared to a tube in which cupper sulphate, sodium hydroxide and a solution of egg white ...
*December 25, 2008 by Ian*

**Chemistry**

Three of the primary components of air are carbon dixode, nitrogen, and oxygen. In a sample containing a mixutre of only these gases at exactly one atmosphere pressure, the partial pressure of carbon dixoide and nitrogen are given as Pco2 = 0.285torr and Pn2=593.525torr. What ...
*March 25, 2009 by Chopsticks*

**statistics**

In response to media inquiries and concerns expressed by groups opposed to violence, the president of a university with over 25,000 students has agreed to survey a simply random sample of her students to find out whether the student body thinks the school’s “Plundering Pirate...
*July 31, 2009 by Bryant*

**chemistry**

Write the equation for the reaction, if any, that occurs when each of the following experiments is performed under standard conditions. a) crystals of iodine are added to an aqueous solution of potassium bromide. b) liquid bromine is added to an aqueous solution of sodium ...
*May 13, 2007 by Krystal*

**Math-Help Please**

Can someone help me figure this out? 1. Find the first and third quartiles, Q1 and Q3 of the following numbers: 347,242,146,391,249,567,277,218,319 and 0.16,0.08,0.27,0.20,0.22,0.32,0.25,0.18,0.28,0.27 2. Which of the following numbers are integers? 75,9.82,-1/14,-498,0.71 The...
*March 5, 2007 by Denim*

**PLEASE HELP ME! PLEASE!**

1 )3x + 8y = 1 7x + 4y = 17 Answer: (3,1) 2) -3x + 5y = -7 9x + 2y = 38 Answer: (4,1) 3) 7r + 3s = 13 14r - 15s = -16 Answer: (1,2) 4) 2x - 7y = 42 4x - 14y = 64 Answer: No Solution ?? 5) 9x + 12y = 15 3x + 4y = 5 Answer: Identity ?? 6) 2 = 4s - 3t 2 = 12s - 9t Answer: No ...
*February 25, 2009 by Veronica*

**chem**

Use Henry's law and the solubilities given below to calculate the total volume of nitrogen and oxygen gas that should bubble out of 1.2L of water upon warming from 25C to 50C . Assume that the water is initially saturated with nitrogen and oxygen gas at 25C and a total ...
*January 25, 2010 by rc*

**Biology Chemistry Part**

I'm trying to calculated the rate of reaction In this lab I took a 50 mL beaker and poured in 10 ml of cold distilled water into it, I then poured in 30 ml of original enzyme solution (I believed we used cold potato juice or something), I then took a piece of paper and placed ...
*September 26, 2010 by Kate*

**chemistry-molarity**

Say I have 50 mL of bromocresol green indicator. This solution has 80mg/L. the molar mass is 698 g/mol. Then say I took 10 mL of that solution and dilute it with .4 M HCI. I want to find the concentration/molarity of bromocresol green. This is what I have attempted to do: 10ml...
*August 2, 2010 by Anonymous*

**Engineering **

The angular velocity of a rigid body rotating about an axis of rotation is w = 5^i + 2^j - 4^k rad. per. sec. Determine the linear velocity of point B on the body with a position vector r = 3^i - ^j + 3^k ft. directed from a point on the axis of rotation. Would the solution ...
*February 12, 2012 by Aaron*

**Science**

1. What is molarity of products? I can't decide if it's a. The concentration of the reactants measured in mol/L of solution or b. The concentration of the products measured in mol/L of solution 4. How does pressure relate to reaction rates? I'm stuck between a. Pressure is ...
*May 7, 2013 by mysterychicken*

**Science**

1. What is molarity of products? I can't decide if it's a. The concentration of the reactants measured in mol/L of solution or b. The concentration of the products measured in mol/L of solution 4. How does pressure relate to reaction rates? I'm stuck between a. Pressure is ...
*May 9, 2013 by mysterychicen*

**physiology**

Is the following statement True or False, and Why? The presence of a hyperosmotic solution in the duodenum will stimulate gastric emptying. True; this helps to speed up the absorption process True; the hyperosmotic solution draws contents in from the stomach False; this causes...
*April 26, 2010 by Anna*

**BioChem**

I have a hard time with this question. Please help. One way to determine the concentration of protein in a solution is to perform a "protein assay". There are several assay kits on the market that one can use, but they all rely on the common paradigm that the aromatic amino ...
*June 17, 2006 by Jamshid*

**Chemistry - titration lab**

Hello. For my chemistry of solutions class, we had a titration lab where we titrated NaOH into an HCl + H2O mix. This was a preparatory titration for the next one consisting of the hydrolysis of ethyl acetate into acetic acid with H+ ions as a catalyst (in our case the HCl). ...
*July 31, 2012 by Robertq*

**Statistics**

For all of the following use the five step process to solve the problem in the question, that is, state the null hypothesis, the alternative hypothesis, the level of significance and the type of test (z-test, t-test, p-value, confidence limit and whether it is two tailed, one-...
*November 11, 2011 by Kristi*

**STATS**

1-Suppose that the fuel comsumption of cars for the same model is normally distributed. A random sample of ten new cars of the same model are randomly selected and their fuel consumption (l/100 km) is determined by subjecting them to a road test of 500 km. Their mean fuel ...
*April 1, 2010 by Judy and group*

**Chemistry**

Calculate the freezing point depression and osmotic pressure at 25 degrees C of an aqueous solution of 1.0 g/L of a protein (mol wt= 90,000) if the density of the solution is 1.0 g/mL. I know how to calculate freezing point depression and osmotic pressure, but I'm having ...
*March 24, 2007 by Jessica*

**Chemistry**

The quantity of antimony in an ore can be determined by an oxidation-reduction titration with an oxidizing agent. The ore is dissolved in hot, concentrated acid and passed over a reducing agent so that all the antimony is in the form Sb3 (aq). The Sb3 (aq) is completely ...
*December 2, 2012 by Anon*

**Chemistry**

The quantity of antimony in an ore can be determined by an oxidation-reduction titration with an oxidizing agent. The ore is dissolved in hot, concentrated acid and passed over a reducing agent so that all the antimony is in the form Sb3 (aq). The Sb3 (aq) is completely ...
*December 3, 2012 by Anon*

**Chemistry**

A student was given 100mL of HCL solution in a 250mL beaker and told that the HCL was 0.11M. The student was also given phenolphthalein indicator and 250 ML of 0.1234 M NaOH. The student first filled a buret with NaOH solution. The student then placed an appropriate volume of ...
*November 21, 2013 by Lenny*

**HCl - Chem**

Assume you had a very magnified view of a solution of HCl that allowed you to "see" the HCl. Draw this magnified view. If you dropped in a piece of magnesium, the magnesium would disappear and hydrogen gas would be released. Draw this out using symbols to represent the ...
*January 13, 2007 by Gil*

**Science**

Ms. Lewis is a chemist mixing two solutions together. A chemical reaction takes place, and the solution becomes warm. Which statement best describes what has happened? A. Energy has been created in the form of thermal energy B. Energy has been transformed from one form to ...
*February 2, 2013 by Anne*

**chemistry**

If you have a solution that is 1.7 M sodium chloride and you have 1 L of that solution, how many moles of sodium chloride do you have?
*October 28, 2011 by emily*

**Chemsitry**

The Ksp of PbBr2 is 6.60× 10^–6. What is the molar solubility of PbBr2 in pure water? What is the molar solubility of PbBr2 in 0.500 M KBr solution? What is the molar solubility of PbBr2 in a 0.500 M Pb(NO3)2 solution?
*March 17, 2013 by Anon*

**Physical Science**

1. What is molarity of products? I can't decide if it's a. The concentration of the reactants measured in mol/L of solution or b. The concentration of the products measured in mol/L of solution 4. How does pressure relate to reaction rates? I'm stuck between a. Pressure is ...
*May 6, 2013 by mysterychicken*

**Physical Science**

1. What is molarity of products? I can't decide if it's a. The concentration of the reactants measured in mol/L of solution or b. The concentration of the products measured in mol/L of solution 4. How does pressure relate to reaction rates? I'm stuck between a. Pressure is ...
*May 6, 2013 by mysterychicken*

**chemistry**

1. Nitrogen gas and sodium liquid are produced by the decomposition of sodium azide NaN3 (s). what volume of nitrogen gas, measured at 25 C and 0.980 atm, is produced by the decomposition of 62.5 g of sodium azide? 2. A gas sample in a container with a volume “V” at a ...
*December 9, 2010 by Helen*

**Please help with Chemistry?????**

5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the mixed ...
*February 26, 2014 by Dan*

**business statistics**

In response to media inquiries and concerns expressed by groups opposed to violence, the president of a university with over 25,000 students has agreed to survey a simply random sample of her students to find out whether the student body thinks the school’s “Plundering Pirate...
*July 30, 2009 by Josephine*

**business statistics**

In response to media inquiries and concerns expressed by groups opposed to violence, the president of a university with over 25,000 students has agreed to survey a simply random sample of her students to find out whether the student body thinks the school’s “Plundering Pirate...
*August 1, 2009 by Tonya*

**Big review 4 finals (2 posts in 1) check my work**

A 7.58 gram sample of benzoic acid, C6H5CO2H, is dissolved in 100 mL of benzene. The density of benzene is 0.879 g/mL. What is the molality of the benzoic acid? Sol: Convert mL to grams benzene. 100 mL * (0.879g benzene/1 mL) = 87.9 g Molality = # molsolute / # kg solvent So I...
*June 14, 2006 by Kizner (chem)*

**Chemistry**

You are carrying out the titration of 100.0 mL of 1.000M acetic acid with 1.000 M sodium hydroxide. Ka = 1.76x10^-5 of acetic acid. (a) Calculate the initial pH of your acetic acid sample. (b) Calculate the pH of the solution after the addition of 25.0mL of NaOH. For (a) ...
*May 13, 2008 by Donna*

**Chemistry**

I have 2 chemicals, A & B. Note: both do not contain buffer salts. Chemical A expires 1 week later. Chemical B expires next year. I prepare solution C (general laboratory reagent)containing Chemicals A & B. When assigning the expiry date of solution C, does this mean the ...
*July 23, 2011 by anne*

**Algebra**

Snape has 2000 mL of a magic potion that is 30% DeMuggle Juice. He also has hundreds of 25 mL bottles that are full of 75% DeMuggle Juice solution. Every time he waves his wand, one of these bottles is added to his magic potion. How many times must he wave his wand to have a ...
*February 6, 2009 by Meghan*

**chemistry**

thank you for any help possible. Given a Mass Percent 13.3% and a Mass Solvent of 325.2 g, find Mass of Solute and Mass of Solution. Mass%=13.3% Mass solvent= 325.2g solve for the Mass solute and Mass solution. This is all the information I am given.
*December 4, 2011 by ben 16*

**Algebra 2 Helpp :(**

QUESTIONS (vvv) (1) Solve the system by subsitution 2x + y = -11 3 - 4y = 11 (2) Solve the system by elimination 2x + 6 = -12 5x - 5y = 10 (3) What is the solution of the following system? -3x - 2y = -12 9x + 6y = -9 (4) What is the solution of the following system? x - y = 11...
*October 23, 2012 by Robert*

**Chemistry**

When 50 mL of 1.0 M AgNO3 is added to 50 mL of 0.50 M HCl, a precipitate of AgCl forms. After the reaction is complete, what is the concentration of silver ions in the resulting solution? (a) 0.50 M (b) 1.0 M (c) zero (d) 0.25 M (e) 0.75 M How do I go about solving this? I ...
*February 1, 2010 by Anonymous*

**INTRO TO STATISTICS HYPOTHESIS TESTING**

Math Horizons is a publication of the Mathematical Association of America. A recent issue reports that in the United States, graduating mathematics majors who also have studied actuarial science have an average first year income of 49,600. Suppose a random sample of36 recent ...
*March 19, 2010 by Gweedo8*

**government**

which of the following steps in scientific polling comes FIRST? a. tabulating the data b. constructing the sample c. preparing valid questions d. defining the universe c
*December 27, 2007 by jere*

**government**

a popular movie star who speaks publicly about a political issue may become a. an opinion leader b. a pollster c. a random sample d. a mandate c
*December 28, 2007 by jere*

**Chemistry**

Which of the following is an example of a Homogeneous mixture? a. the hydrogen and oxygen atoms that make up water b. A typical soil sample c. a bottle of table vinegar
*July 7, 2008 by Mickey*

**chem lab**

If a sample tube was smudged with a fingerprint when inserted into a spectrometer, what affect would this have on the value of A (absorbance) when you read it? explain.
*November 13, 2008 by Mischa*

**Chemistry/math**

Cesium-137 has a half-life of 30 years. Suppose a lab stored a 30-mCi sample n 1973. How much will be left in 2063?
*April 15, 2009 by Angie*

**integrated marketing communication**

can you guys please help me or give me a link of some sample of STP(segment target postioning) of any market thank you very much
*December 6, 2009 by like roses*

**physics**

Determine how much water would be present in a 10 tonne sample of lignite, has a moisture content of 65%, before crushing and drying. 10 tonnes is 10,000 kg.
*March 10, 2010 by sasha*

**statistics**

Given that a sample is approximately bell-shaped with a mean of 60 and a standard deviation of 3, the approximate percentage of data values that is expected to fall between 54 and 66 is
*August 22, 2010 by Anonymous*

**chemistry**

Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure. Which gas sample has the greatest number of molecules?
*October 27, 2010 by Tasha*

**Chem**

I've been having trouble setting up word problems. Here is one problem I need help with. How many Bromide ions are in a sample of CaBr2 that has a mass of 10.0g?
*November 18, 2010 by Nescha*

**Chemistry**

When determining boiling points, why would you need to repeat your experiment if your sample completely vaporized before you were able to obtain a constant temperature?
*December 1, 2010 by Ash*

**Chemistry**

When determining boiling points, why would you need to repeat your experiment if your sample completely vaporized before you were able to obtain a constant temperature?
*December 1, 2010 by Ash*

**ap ch em**

004 10.0 points To what temperature must a sample of helium gas be cooled from 144◦C to reduce its volume from 4 L to 0.86 L at constant pressure? Answer in units of K.
*April 3, 2011 by Anonymous*

**Stats**

Angela is conducting a poll on campus to determine the next student representative. How many students does she need to sample for a confidence level of 90% with a margin of error of + or - 5%?
*May 14, 2011 by Ana*

**Statistics**

Angela is conducting a poll on campus to determine the next student representative. How many students does she need to sample for a confidence level of 90% with a margin of error of + or - 5%?
*May 15, 2011 by Ana*

**stattistics**

The p-chart is based on the assumption that the number of defective units in each sample is a binomial random variable. Choose one answer. A. True B. False
*June 22, 2011 by bharat*

**Lab Porcedures**

A small sample taken from the body and placed on a medium to allow bacteria growth is a A. profile B. culture C. serum D. specimen Is B correct
*August 17, 2011 by Eileen*

**Statistics**

Given the list 10,7,5,3,-6 find by hand, mean,meadian, midrange, mode(s), range, popvar, and sample standard deviation. (seven problems)
*September 10, 2011 by marie *

**Chemistry**

If 1.000g of (potash) K2CO3 reacts with H2SO4 to produce 145 mL of CO2 gas at STP, what is percentage of Potassium Carbonate in the marble sample?
*October 15, 2011 by Sarah J*

**Statistics**

Given that a sample is approximately bell-shaped with a mean of 60 and a standard deviation of 3, the approximate percentage of data values that is expected to fall between 54 and 66 is
*January 22, 2012 by Dawn*

**Business Research**

5. What is the difference between a probability and a nonprobability sampling strat- egy? Provide an example of each. Also, what are the advantages and disadvantages of each type of sample?
*January 25, 2012 by Lindsey*

**Chemistry**

If 30% of a sample of radioactive isotope decays in 24 hrs, what is the half-life? How do i know which order to use? and do I convert hr to mins or seconds? Pls help for my exam tomorrrow
*February 23, 2012 by tina*

**Stats**

Given that a sample is approximately bell-shaped with a mean of 60 and a standard deviation of 3, the approximate percentage of data values that is expected to fall between 54 and 66 is 75% 95% 68% 99.7%
*March 3, 2012 by Ashley*

**statistics**

Fit a regression line = a+bXi by the method of Least squares to the given sample information. Observations 1 2 3 4 5 6 7 8 9 10 Income (X)(’00 Rs) Consumption Expenditure(Y)(’00 Rs) 10 44 5 60 25 39 37 51 96 80 94 70 110 80 30 30 79 50 65 40
*March 12, 2012 by Anonymous*

**Political Science**

True or False Calling randomly selected phone numbers is the main method pollsters use to gather a random sample.
*March 14, 2012 by tina*

**college **

Consider a normal population with μ = 36 and σ = 4.9. Calculate the z-score for an x of 47.6 from a sample of size 14. (Give your answer correct to two decimal places.)
*July 23, 2012 by samantha*

**math Statistics**

Suppose that 33 out of 300 selected american drivers read the newspaper while driving. what percent of sample proportions are greater than this?
*February 18, 2013 by jessica *

**statistics**

Assume you want to estimate with the propoportion of student who commute less than 5 miles to work(20) with in 2%, what sample size would you need. Total in survey is 233
*February 28, 2013 by kathy L*

**Statistics**

Suppose that A and B are events defined on a common sample space and that the following probabilities are known. Find P(A or B). (Give your answer correct to two decimal places.) P(A) = 0.34, P(B) = 0.41, P(A | B) = 0.2
*June 8, 2013 by Carl*

**Math check**

Consider a normal population with ì = 49 and ó = 6. Calculate the z-score for an x of 44.2 from a sample of size 22. (Give your answer correct to two decimal places.) 44.2-49/6/22^=.00165=.00
*June 13, 2013 by Sue 74*

**Chemistry**

Diarsenic trioxide is the number one source of arsenic; determine the mass of a sample of this extremely poisonous material containing 4.03x10^18 molecules.
*September 29, 2013 by Tired*

**chemistry lab**

list the possible manipulation errors that might contribute in obtaining a significantly larger amount of nacl than was present in original sample
*October 4, 2013 by miranda*

**physics**

How long will it take a sample of polonium-210 with a half-life of 140 days to decay to one-sixty-fourth of its original strength?
*January 15, 2014 by katie*

**chemistry**

one litre of a sample hard water contain 4.44mg cacl2 and 1.9mg of mgcl2. What is the total hardness in terms ppm of cac03?
*June 29, 2014 by ken*

**chemisty**

Posted by STACY on Monday, December 13, 2010 at 7:56pm. Consider an aqueous solution prepared from 250.0 mL of water and 1.27 g of potassium bromide. Express the amount of potassium bromide in this solution in terms of (a) mass percent (b) mole fraction (c) molarity assume the...
*December 14, 2010 by STACY*

**college Chemistry**

1. If 25 grams of Iron (III) hydroxide is dissolved in a 500mL volumetric flask, what is the Molarity of the solution? 2. An unknown metal has a volume of 5.25 mL and a density 2.71 g/mL. What is the weight of the metal in grams? 3. An unknown metal, heated to an unknown ...
*December 4, 2010 by Ivy *

**chem **

what color change happen when you add a solution containing Ag+ ion to the mixture AgSCN? How is this consistent with LeChatelier's principle? pls correct my answer. my answer is a more white solid or pecipitate form due to insoluble AgSCN. It is consistent with LeChatelier's ...
*November 25, 2012 by Andrew78*

**chem**

what color change happen when you add a solution containing Ag+ ion to the mixture AgSCN? How is this consistent with LeChatelier's principle? pls correct my answer. my answer is a more white solid or pecipitate form due to insoluble AgSCN. It is consistent with LeChatelier's ...
*November 25, 2012 by Andrew78*

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