Wednesday

September 2, 2015
Number of results: 28,174

**biology**

You are attempting to determine whether a plant-derived processed food sample (for example, a corn chip) contains material from a genetically-modified organism (GMO). First, you crush the sample and attempt to extract DNA from it. Next, you perform PCR using two different sets...
*July 22, 2011 by patricia*

**Chemistry**

If 50.00mL of 1.10M NaOH is added to 25.00mL of 1.86M HCl, with both solutions originally at 24.70 degrees Celsius, what will be the final solution temperature? (Assume that no heat is lost to the surrounding air and that the solution produced in the neutralization reaction ...
*October 5, 2012 by Tasnim*

**math**

Beer cans are right circular cylinders. My Mathematical Mead, My Polynomial Pilsner, and my Square-root Stout cans, from the Schmidt Brewery, have dimensional units called "brewskies." They have a volume (in cubic brew skies) equal to a solution of the function: f(x)=-24pi x^2...
*April 24, 2013 by Anonymous*

**chemistry**

Saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten tablets with total mass of 0.5797 g were dissolved in water. The solution was then oxidized to convert all the sulfur to sulfate ion, which was precipitated by adding an excess of barium chloride solution. The ...
*October 27, 2010 by Anonymous*

**Chemistry 120**

A sloution of calcium nitrate, C(NO3), reacts with a solution of ammonium fluoride, NH4F, to form solid calcium fluoride, CaF2, and ammonium nitrate, NH4NO3(ag). When 45.00 mL of 4.8724 x 10 -1M Ca(NO3)2 solution was added to 60.00 mL of 9.9981 x 10 -1M NH4F solution, 1.524g ...
*February 10, 2010 by Macey*

**chemistry**

A nitric acid solution of unknown concentration is used to titrate 0.771g of sodium tyrosinate (NaC9H10NO3). If the endpoint is reached when 32.79mL of nitric acid has been added, what is the concentration of the unknown nitric acid solution?
*March 6, 2013 by Anonymous*

**Algebra 1 **

1. A chemistry student needs to make a solution that is 70% water and 30% hydrochloric acid. The student's current mixture of 300 ml is 60% water and 40% hydrochloric acid. How much water must the student add to achieve his desired solution? A: ? 2. 5. 2/t + 4/3t = 4/t + 2 A: ...
*June 3, 2014 by Victoria*

**Chemistry**

the equation of the line for a graph of voltage versus log[Cu2+] was y= - 0.0179x - 0.0015. The voltage of a solution with an unknown [Cu2+] was measured against the same reference cell, under the same conditions; the voltage was found to be 0.012 V. Determine the [ Cu2+] of ...
*June 14, 2011 by Daniel*

**Chemistry**

The equation of the line for a graph of voltage versus log[Cu2+] was y= - 0.0179x - 0.0015. The voltage of a solution with an unknown [Cu2+] was measured against the same reference cell, under the same conditions; the voltage was found to be 0.012 V. Determine the [ Cu2+] of ...
*June 15, 2011 by Max*

**Science repost for iiii**

science - iiii, Monday, October 29, 2007 at 8:08pm What test would you need to perform to prove that it is the combination of glucose and the Glucose Indicator Solution that changes color when heated and not just the glucose or the Glucose Indicator Solution alone? Support ...
*October 29, 2007 by Ms. Sue*

**chemistry**

1)If 746.4 g of a substance is dissolved in 1723 g of benzene solvent, the freezing point of the solution is -9.19 oC. Calculate the apparent molar mass (g/mol) of substance. 2) What mass ( g ) of the solvent water should be mixed with 0.008595 L of the solute ethylene glycol ...
*January 20, 2010 by bubble*

**Chemistry**

Hi, I am trying to figure out how to calculate the average temperature of 2 different chemical solutions based upon the temperatures I measured. The question states: Find the average Ti of HCl & NaOH solutions. The Ti of NaOH solution is: 20.87 C The Ti of HCl solution is: 21....
*March 12, 2012 by Jules*

**Math**

what is the solution to x + 4 = 12? A. X = 16 B. X = 12 C. X = 8 (MY ANSWER) D. X = 4 What is the value of b is 9 + b = -8 A. b = -17 B. b = -1 C. b = 1 D. b = 17(MY ANSWER) What is the solution to q + (-9) = 12? A. q = -21 B. q = -3 C. q = 3 ( MY ANSWER) D. q = 21 Are my ...
*August 25, 2014 by HELPPP 911 HELP*

**Statistics**

1.What is the p value (“significance level”)? What does this p value mean? 2.How does the n (sample size) of this sample affect the r and p values? 3.Is there a relationship between assertiveness and whether one holds anger “in”? Descriptive Statistics Mean Std. Deviation N ...
*June 16, 2010 by Donald*

**Chemistry - Equilibrium**

Silver ion concentrations are needed for a solution. You have 0.050 M AgNO3, if you added 5.0mL of 12. M NH3 to 500.mL of this solution, how much silver ion in M will you have at equilibrium? [Kf for Ag(NH3)2+ is 1.5 x 10^7]
*April 25, 2012 by Shawn*

**Math**

Given the following LP model (represented abstractly with decision variables X and Y), find the optimal solution using the ‘graphing’ approach. Minimize 5X + 2Y Subject to: 4X + 2Y >= 80 3X + 4Y <= 132 X + 3Y >= 45 2X - Y >= 0 And non-negativity, of course. Your ...
*September 22, 2011 by Rick*

**Statistics- HELP!**

2. The Rathburn Manufacturing Company makes electric wiring, which it sells to contractors in the construction industry. Approximately 900 electric contractors purchase wire from Rathburn annually. Rathburn's director of marketing wants to determine electric contractors' ...
*February 11, 2013 by Betty*

**Spanish Persausive Essay**

Identify a problem that involves the Spanish language in some way. Your choice! (Example: Unfairness/bias issues in highstakes testing for ESL students) Propose a solution to the problem. And then support and develope your solution into a persuasive writing piece. (Doesn't ...
*March 15, 2009 by Holly*

**statistics**

Waste Today Services operates a garbage hauling company in a South Jersey city. Each year, the company must apply for a new contract with the city. The contract is in part based on the pounds of garbage hauled. Part of the analysis that goes into the contract development is an...
*April 18, 2012 by Marsha*

**Chemistry**

Sorry Dr. Bob, I wsa looking for the Sucrose, not all 16 calculations. Can you help me with the Sucrose? I have 93.954 mL of a generic cola solution. The solution contains: Molarity of H++1.005e-7 Molarity of OH- = 1.005e-7 Molarity of Sucrose(aq) = 6.386e-1 Molarity of Dye= ...
*November 3, 2011 by Emily*

**chemistry**

Hi, The problem is: "Calculate the concentration of OH- and the pH value of an aqueous solution in which [H30+] is 0.014M at 25C. Is this solution acidic, basic, or neutral?" I have calculated the OH- concentration to be: 7.1 X 10^-14 When I calculate the pH (using H30+), I ...
*March 30, 2011 by LaurenM*

**Chemistry**

Calculate the concentration of bromocresol green (BG) indicator It says that Molar absorptivity = Absorbance at a wavelength/ concentration of BG indicator I am having trouble calculating the concentration of BG. Other info: Stock solution of BG = 80.0 mg/L and molar mass = ...
*April 25, 2013 by Catherine*

**MAths**

Consider the following system of inequalities: (c−1)x^2+2cx+c+4≤0 ---- (1) cx^2+2(c+1)x+(c+1)≥0 ---- (2) The sum of all real values of c, such that the system has a unique solution, can be written as a/b, where a and b are coprime positive integers. What is ...
*April 29, 2013 by ianian*

**algebra**

Consider the following system of inequalities: {(c−1)x^2+2cx+c+4≤0 cx^2+2(c+1)x+(c+1)≥0 The sum of all real values of c, such that the system has a unique solution, can be written as ab, where a and b are coprime positive integers. What is the value of a+b? ...
*May 2, 2013 by Pool*

**maths**

Consider the following system of inequalities: {(c−1)x^2+2cx+c+4≤0 cx^2+2(c+1)x+(c+1)≥0 The sum of all real values of c, such that the system has a unique solution, can be written as ab, where a and b are coprime positive integers. What is the value of a+b? ...
*May 3, 2013 by sara*

**Analytical Chemistry**

5mL of a solution A (unknown concentration) was transferred into sic 25mL volumetric flask. The following volumes of a standard solution of A with with a concentration 75ppm were added to the flask: 0mL, 0.5mL, 1mL, 1.5mL, 2mL, and 2.5L. The excitation spectrum and and ...
*May 8, 2015 by Katy*

**statistics**

experience in investigating insurance claims show that the averagecost to process a claim is approximately normally distributed witha mean of $80.new cost-cutting measures were started and a sampleof 25 claims was tested .the sample mean of the costs to processthese claims was...
*December 15, 2012 by gina*

**stats**

18. Numerous studies have found that males report higher self-esteem than females, especially for adolescents (Kling, Hyde, Showers, & Buswell, 1999). Typical results show a mean self-esteem score of M = 39.0 with SS = 60.2 for a sample of n =10 male adolescents and a mean of ...
*October 7, 2014 by Anonymous*

**statistics2**

A textbook publisher wants to determine process control charts for the textbook height. The following table shows the first 20 samples of n=4 sample size of the production of the text. Sample - X Bar - Range 1 - 10.01 - .01 2 - 9.97 - .04 3 - 9.98 - .03 4 - 10.01 - .04 5 - 10....
*January 30, 2009 by Johnny*

**chemistry**

Can you check what I did below? On the first problem, I am not sure if I am suppose to add a negative to the first part of the heat loss of water like so -[C(sp)m(w)deltaT(w)]. On the second problem, part(a), I am not sure if I am using the mass from the first problem, 135g, ...
*July 19, 2008 by Anonymous*

**Thermodynamics**

Steam in a cylinder-piston arrangement expands from an initial condition of 5 bar, 80% dry to a final state of 2 bar, dry saturated steam. The initial volume of steam is 0.8 m3. The process of expansion can be represented by a straight line on the p–Vdiagram. 5B. What is the ...
*October 17, 2014 by Phy*

**Chemistry 3**

How is it possible for me to tell which of these solutes will produce an acidic solution when dissolved in water? LiOH CH3CO2K H2SO3 KOH NaOH NH4NO3 NaOH NaOH can't be the only one... Molecules that produce OH^- when dissolved in water will be basic. Examples:LiOH, KOH, NaOH, ...
*May 24, 2007 by Lindsay*

**chemistry**

a solution is prepared by mixing 2.17g of an unknown non-electrolyte with 225.0g of chloroform. The freezing point of the resulting solution is -64.2 C . The freezing point of pure chloroform is -63.5 C and its kf= 4.68C m^-1 . What is the molecular mass of the unknown? i know...
*February 10, 2014 by hershi*

**Prob and Stats**

To estimate the mean height population of male students on your campus, you will measure and SRS of students. Heights of people the same sex and similiar ages are close to normal. You know from government data that the standard deviation of the heights of young men is about 2....
*October 12, 2010 by Susan*

**Math**

The National AIDS Behavioral Surveys interviewed a sample of adults in the cities where AIDS is most common. This sample included 789 heterosexuals who reported having more than one sexual partner in the past year. We can consider this an SRS of size 789 from the population of...
*May 6, 2012 by Janel*

**CHEM**

I know I posted this question again but no one is really helping me. Can someone please help me as soon as possible. In a constant-pressure calorimeter, 60.0 mL of 0.340 M Ba(OH)2 was added to 60.0 mL of 0.680 M HCl. The reaction caused the temperature of the solution to rise ...
*February 10, 2012 by Akle*

**statistics**

Starting with a population that is normally distributed with a mean of 100 and a standard deviation of 12, answer the following questions (if possible). a. What is the probability of randomly drawing a single score between 100 and 106, p(100 < X < 106)? b. What is the ...
*October 15, 2011 by Daniel*

**chemestry**

A calorimeter contains 16.0 of water at 15.0. When 1.60 of (a substance with a molar mass of 58.0 ) is added, it dissolves via the reaction and the temperature of the solution increases to 27.5. Calculate the enthalpy change, , for this reaction per mole of . Assume that the ...
*November 9, 2011 by Anonymous*

**Chemictry**

A calorimeter contains 32.0 of water at 11.5. When 1.70 of (a substance with a molar mass of 74.0 ) is added, it dissolves via the reaction and the temperature of the solution increases to 26.5. Calculate the enthalpy change, , for this reaction per mole of . Assume that the ...
*November 18, 2011 by Priscilla*

**chemistry**

A chemistry student weighs out 0.172 grams of acrylic acid (HCH2CHCO2) into a volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1800 moles/liter NaOH solution. Calculate the volume of NaOH solution the student will need to add ...
*January 25, 2012 by Lucas*

**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 ...
*February 24, 2012 by Katie*

**Chemistry**

Are these reactions Exothermic or Endothermic? How do I know? 1.) Mg(OH)2(s)<==>Mg+2(aq) + 2OH-(aq) Saw solution lighten from medium pink to very light when heated in hot water bath. (It had phenolphthalein drop for indicator.) 2.) HSO4-(aq)+ H2O(l)<==>H3O+(aq)+SO4...
*July 11, 2013 by Ann*

**algebra**

Use the discriminant to determine the following equations have that are two different rational solutions:two different irrational solutions or exactly one rational solution or two different imaginary solution. x^2=5x+6
*June 9, 2011 by mema*

**CHEMISTRY**

25cm^3 of a solution of NaOH required 28cm^3 of 1.0 mol dm^-3 H2SO4 to neutralise it. a)Write an equation for the reaction. b)How many moles of H2SO4 were needed? c)How many moles of NaOH were thus neutralised? d)How many moles of NaOH are there in 25cm^3 of solution?
*October 20, 2013 by Ava*

**chemistry**

A student determines the zinc content of a solution by first precipitating it as zinc hydroxide, and then decomposing the hydroxide to zinc oxide by heating. How many grams of zinc oxide should the student obtain if her solution contains 42.0 mL of 0.566 M zinc nitrate?
*November 4, 2012 by Anonymous*

**chemistry**

A student determines the cobalt(II) content of a solution by first precipitating it as cobalt(II) hydroxide, and then decomposing the hydroxide to cobalt(II) oxide by heating. How many grams of cobalt(II) oxide should the student obtain if her solution contains 46.0 mL of 0....
*March 3, 2014 by jen*

**Chemistry**

A student determines the iron (II) content of a solution by first precipitating it as iron (II) hydroxide, and then decomposing the hydroxide to iron (II) oxide by heating. How many grams of iron (II) oxide should the student obtain if her solution contains 46.0 mL of 0.426 M ...
*October 16, 2014 by Jessica*

**chemistry**

Experiment: Gravimetric Determination of Phosphorus in Fertilizer Samples 1. Can NH4Cl be used as a substitute to precipitate the phosphorus in the sample? Why or why not? - I think, NH4Cl can be used although I'm not quite sure if Cl- ions have some effects to the ...
*August 17, 2007 by Smiley*

**Chemistry**

Q1 In order to determine the concentration of acetic acid in a sample of vinegar, a student titrated a sample of vinegar with potassium hydroxide solution. Dada from four trials was collected and recorded in a data table. Titiration of 10.0 mL of CH3COOH(aq) with 0.250 mol/L ...
*September 28, 2006 by Brittany Rusk*

**Biology**

The absorbance of a protein solution measured in a 1.0 cm cuvette at 278 nm was 1.145. The protein content of that solution, calculated from quantitative amino acid analysis, was 256 micrograms/mL. Calculate the extinction coefficient of the protein in unitsbof mL/mg/cm. ...
*October 12, 2009 by Anonymous*

**chemistry**

We have two liters of a buffer solution that is 0.10 M in CH3COOH and 0.10 M in NaCH3COO. How many moles of solid NaOH are to be added to this solution to increase its pH by 5.0 percent? Assume no volume change due to the addition of solid NaOH. I have the starting pH and what...
*April 15, 2010 by Bharg*

**chemistry**

A student performs a back-titration to determine the cost -effectiveness of an antacid. A tablet with a retail cost of $0.053 is dissolved in 25.00 ml of 1.000 M HCl, then back-titrated with 1.000 M NaOH. Exactly 14.82 ml of NaOH solution is required to reach the endpoint. ...
*April 19, 2010 by Lisa*

**Chemistry**

the following questions are about colligative properties: a)How much would the freezing point change in a 2.5 solution of phenol in benzene? b)how much would the boiling point change in a 1.m solution of magnesium chloride in ethanol? c)Does adding sugar to water raise or ...
*May 2, 2010 by Kim*

**Chemistry (URGENT)**

Calculate the molarity of the Co^2+ ion in each of the solutions 1-5. The new molarity is given by the molarity of the stock solution multiplied by the dilution factor. Solution: Co(NO3)2 Original molarity: 0.160 Dilution #1: none D#2: 12mL to 16mL D#3: 8mL to 16mL D#4: 4mL to...
*December 15, 2010 by John*

**chemistry**

In the following experiment, a coffee-cup calorimeter containing 100 mL of H20 is used. The initial temperature of the calorimeter is 23.0 C . If 3.60 g of CaCl2is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of the ...
*October 20, 2011 by Colin*

**Statistics**

The American Academy of Pediatrics (AAP) recommends that kids 2-5 years old watch no more than (on average) 1.6 hours a day of quality programming. A researcher selected a sample of 101 kids in the neighborhood and asked their parents how many hours per day they allow their ...
*October 4, 2013 by Chris*

**statistics**

2) Two individuals are running for mayor of Tallahassee. You conduct an election survey (N = 561) a week before the election and find that 57% of the respondents prefer candidate A. Can you predict the winner (α = 0.01)? (Hint: Use 50% as the proportion of votes needed ...
*March 18, 2009 by taryn*

**statistics**

4. Are women getting taller? In one state, the average height of a woman aged 20 years or older is 63.7 inches in 1990. A random sample of 100 women is taken to test if women’s mean height today is different from 1990. The mean height of the 100 surveyed women is 63.9 inches. ...
*December 16, 2013 by Amanda*

**Chemistry**

A solid weak acid is weighed, dissolved in water and diluted to exactly 50.00 ml. 25.00 ml of the solution is taken out and is titrated to a neutral endpoint with 0.10 M NaOH. The titrated portion is then mixed with the remaining untitrated portion and the pH of the mixture is...
*April 14, 2015 by JUNDY*

**statistics**

The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airports. The maximum possible rating is 10. Suppose a simple random sample of 50 business travelers is selected and each traveler is asked to provide a ...
*April 21, 2014 by Vanessa*

**statistics (6)**

The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airports. The maximum possible rating is 10. Suppose a simple random sample of 50 business travelers is selected and each traveler is asked to provide a ...
*April 22, 2014 by Vanessa*

**statistics (6)**

The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airports. The maximum possible rating is 10. Suppose a simple random sample of 50 business travelers is selected and each traveler is asked to provide a ...
*April 23, 2014 by Vanessa*

**Chemistry**

why mass cannot be used as a property to identify a sample of matter?
*September 6, 2007 by John*

**chemistry**

How many phosphorus atoms are in a 0.3352 g sample of Ca3(PO4)2 ?
*November 25, 2007 by Rog*

**alg**

Find the sample size that produces the margin of error ± 3.0%
*May 12, 2008 by jerson*

**algebra**

Find the sample size that produces the margin of error ± 3.0%
*May 12, 2008 by jerson*

**English**

Can you please show me a sample of a diagrammed sentence with phrases?
*July 20, 2008 by Tyler*

**computers**

where can i play a sample online mixing turntables with music to dj with
*September 18, 2008 by carlos*

**chemistry**

what is the volume of a 2.00 gram sample of helium gas at STP?
*March 5, 2009 by crystal*

**business statistics**

If a sample of size 30 is selected, the value of A for the probability p(>- A) = 0.01 is?
*August 1, 2009 by Bryant*

**Stragies**

What does a sample outline look like for a thesis paper
*May 29, 2010 by Jodi*

**physics**

a 20.0L sample of hydrogen gas has a mass of 1.80g. What will its density be in g/ml?
*July 13, 2010 by Jen*

**Chemistry**

How many grams of iron are there in a sample of Fe3O4 which weighs 8.338 g?
*September 20, 2010 by Diggs*

**chemistry**

How many moles are in a sample of cobalt containing 5.0x10^23 atoms?
*October 21, 2010 by Nathan*

**Science**

How old id an artifact if only 1/4 of the hydrogen 3 in the sample remains?
*January 5, 2011 by Diane*

**Science**

How many days will it take for 3/4 of a sample of polonium 210 to decay?
*January 6, 2011 by Diane*

**chemistry**

a sample of freshly pressed apple juice has a pH of 3.76. Calculate [H+].
*January 20, 2011 by jaycab*

**statistics**

what is teh standard error when sample n = 16 mu=150 and sigma = 36
*January 30, 2011 by Jokes*

**math**

What is the sample space for choosing a letter from the word mathematics
*April 29, 2011 by mia*

**statistics**

Would it be unusual for the mean of a sample of 3 to be 115 or more?
*August 2, 2011 by john*

**chemistry**

What is the density of air if a 5000ml sample has a mass of 0.125?
*September 25, 2011 by eliza Higgins *

**chemistry**

What is the density of air if a 5000ml sample has a mass of 0.125?
*September 25, 2011 by eliza Higgins *

**Science**

How would you obtain a sample of the salt potassium chloride?
*October 16, 2011 by Muhammad tanvir hussain *

**Staitstics**

What statistical test would be appropriate for a sample size of 25
*November 8, 2011 by Tommy*

**Statistics**

Find t-value for sample size n = 16 and area to the right 0.10
*February 22, 2012 by Tina*

**chemistry**

what is the density of a sample of 65.0 ml of automobile oil having mass of 59.82 g
*March 4, 2012 by yvette*

**statistics**

create a survey results that have a sample proportion of 23%
*March 16, 2012 by douglas*

**chemistry**

how many grams of magnesium carbonate are in a sample that has 1.58 x 10^24 oxygen atoms?
*April 24, 2012 by liz*

**Chem**

Can a 100ml sample of 3.0m H2 SO4 could be neutralized by 100 ml of 3.0m NH3
*July 16, 2012 by natalie*

**chemistry**

determine the number of moles of FeSO4 in sample Y that you use
*August 2, 2012 by methove*

**chenistry**

how many calories are required to melt a 135.0g sample of ice at 0.0 c
*September 5, 2012 by barb*

**statistics**

for a sample of 3 to have a mean of 115 would this be unusual
*September 30, 2012 by lillie*

**chemistry**

A sample of oil has a mass of 65g and a volume of 80.0 mL. What is the density?
*October 4, 2012 by sherry*

**chemistry**

how many atoms are in a sample of 175 g of sodium (Na)? 4.58 x 1024 or 1.42 x 1027?
*November 12, 2012 by Anonymous*

**statistics**

What is the standard deviation of 31 sample values with a mean of 2954?
*February 22, 2013 by glenzy*

**Chemistry **

How many moles of ethyl alcohol C2H6O are in a 25.0 sample? How do I calculate?
*March 21, 2013 by Yaneth*

**chemistry**

Which of the following will increase the strength of a sample of 90% SiO2 - 10% MgO
*April 26, 2013 by Anonymous*

**chemistry**

If a 1.60 M sample of A is heated to 500 K, what is the concentration of B at equilibrium? A(aq)<---> 2B(aq) Kc=9.63x10^-6
*April 11, 2014 by Anna*

**statistics**

simple randon sampling uses a sample size n
*June 30, 2014 by Anonymous*

**chemistry**

Calculate the number of C atoms in a .25mg sample of C8H10N4O2
*September 20, 2014 by frank*