Thursday

April 24, 2014

April 24, 2014

Number of results: 11,168

**statistics **

Which of the following criteria must be met to do a one-sample test for a proportion? A. The data values in the sample must be independent. B. The parent population must be normally distributed. C. The data must come from a random sample. D. The sample size must be more than ...
*Thursday, June 27, 2013 at 6:34pm by Katie*

**chemistry help**

1. Calculate the energy change (q) of the surroundings (water) using the enthalpy equation qwater = m × c × ΔT. We can assume that the specific heat capacity of water is 4.18 J / (g × °C) and the density of water is 1.00 g/mL. Show ALL your work. The water has absorbed ...
*Sunday, April 7, 2013 at 9:20am by MadiB PLEASE HELP :(*

**business statistics**

A random sample of size 15 taken from a normally distributed population reveled a sample mean of 75 and a sample variance of 25. The upper limit of a 95% confidence interval for the population mean would equal?
*Saturday, August 1, 2009 at 11:27am by Samantta*

**Statistics - Please help**

An experiment was conducted to determine the abrasion resistance of a new type of automobile paint. Twelve different strips of metal were painted with the new paint. The abrasion resistance of each piece was then tested on a machine. In the sample, the abrasion resistance ...
*Thursday, April 3, 2014 at 3:55pm by Bre*

**Chemistry**

You are given a jar containing a mixture of three different solid substances. The particles of each substance are larger than 0.5 cm in diameter. All you know about the substances is that each is a pure metal. Describe a method for determining the identities of the metals that...
*Tuesday, February 23, 2010 at 7:49pm by Haley*

**chemistry**

An insulated beaker contains 250.0 grams of water at 25oC. Exactly 41.6 g of a metal at 100.0oC was dropped in the beaker. The final temperature of the water was 26.4oC. Assuming that no heat is lost in any other way, calculate the specific heat of the metal. a. 0.159 J g-1 K-...
*Saturday, January 21, 2012 at 9:45pm by utna*

**chemistry**

what transition metal complex is responsible for transporting oxygen in our blood? Also, what is its structure? The transition metal (there are several transition series---I assume you are referring to the 3d transition metals) is iron. As to its sturcure, the iron itself has ...
*Tuesday, April 17, 2007 at 10:32pm by Bob*

**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**

I did a back titration with an unknown carbonate and using the average % carbonate (by mass) which I found to be 27.40% and appropriate calculation decided where the unknown is an alkali metal carbonate or an alkaline earth metal carbonate. I have no idea how to tell the ...
*Monday, March 5, 2012 at 9:06pm by Laura*

**cook**

I want to know wat all the weighing equipment is
*Tuesday, February 4, 2014 at 2:26pm by dylan*

**Chemistry**

The amount of oxalic acid in a sample was determined by the reaction: 2Fe3+ + H2C2O4 + 2H2O----> 2Fe2+ + 2CO2 + 2H3O+. In an analysis, 10.62g of sample required 36.44 ml of 0.013 M Fe3+. Calculate the %w of oxalic acid in the sample.
*Monday, September 1, 2008 at 11:23am by Jimmy*

**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*

**Physics**

7. Two metal spheres are suspended from insulating threads. A negatively charged rod is brought near these spheres. One sphere is pushed away from the rod and the other is attracted toward it. Describe the behavior of the spheres. SOLUTION: ----> {Metal sphere attracted to ...
*Friday, May 29, 2009 at 11:19am by sally*

**Physics**

One hundred twenty grams of metal at 88 degree Celsius is poured into a 70 grams insulated cup contains 250 grams of water at 16 degree Celsius .The final temperature of the mixture is 17.5 degree C.Determine the specific heat capacity of the metal.
*Friday, June 28, 2013 at 5:39am by jey*

**Chemistry**

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...
*Sunday, October 23, 2011 at 3:30pm by Hannah*

**Chemistry**

Shown below is the optical absorption spectra for a material wavenumber=9.1*10e5 Calculate the bandgap of this material. (Express your answer in eV) I'm calculate 1.13eV, but next question I don't know answer: This material is a(an) metal, ionic solid , insulation or ...
*Saturday, November 16, 2013 at 6:48am by DDD*

**Chemistry**

A sample of sucrose, C12H22O11(s),contains 0.16 mol of oxygen, atoms(O). a.) What amount in moles of sucrose is in the sample? b.)How many atoms of carbon are in the sample?
*Monday, April 8, 2013 at 9:17pm by Lg*

**Chemistry**

O.k. I am confused. So here is what I did. Mass of empty flask plus stopper: 37.34g mass of stoppered flask plus water: 63.67g Mass of stoppered flask plus liquid: 52.01g Mass of water: 63.67 - 37.34= 26.33 Volume of Flask(density of H20 at 25*C, 0.9970 g/cm^3: (37.34g)/(0....
*Wednesday, August 22, 2007 at 6:55pm by Sara*

**analytical chemisty**

Consider the standardization of a solution of K2Cr2O7 with iron metal according to the following: Reaction: Fe + Cr2O7-2 → Fe +3 + Cr+3a. How many grams of K2Cr2O7 are required to prepare 500 ml of a 0.13 N solution? What is the exact normality of the solution prepared ...
*Saturday, February 2, 2013 at 7:39pm by Anonymous*

**Physics**

A metal shpere with ane excess of 11 electrons touches an identical metal sphere with an excess of 15 electrons. After the spheres touch, the number of excess electrons on the second sphere is? My book tells me it is 13, but I dont understand why. If someone could explain, I ...
*Tuesday, February 24, 2009 at 1:25pm by Anonymous*

**chemistry**

mass of crucible- 26.4574g mass of crucible and hydrated sample- 27.7617g mass of hydrated sample 1.3043g mass of crucible and dehydrated sample- 27.5693g mass of dehydrated sample- 1.1119g mass of filter paper- 0.7089g mass of filter paper and copper- 1.1418g mass of copper...
*Tuesday, February 19, 2013 at 1:42pm by Johny*

**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*

**Physics **

A cylinder with a piston is filled with ideal gas. The gas temperature is held at 450 K. The cylinder is heated by an oven through a square metal rod connected between the oven and the cylinder. The rod has sides d = 2 cm and length L = 2.3 m. (a) If the oven is held at 850 K...
*Tuesday, November 16, 2010 at 9:35pm by Help*

**Science**

I asked about this earlier and got an answer that caused me to rethink my process. Is this a good way to measure iron corrosion: weigh a nail, put it in water and let it rust, remove the rust (in my experiment the rust has come off easily, with just a wipe), and weigh it again...
*Sunday, November 26, 2006 at 1:57am by Jane*

**chemistry**

A 115 g piece of metal, initially at 60.0 °C, is submerged into 100.0 g of water at 25.0 °C. At thermal equilibrium, this mixture had a final temperature of 27.0 °C. The specific heat capacity of water is 4.18 (J/g°C). Use this information to determine the specific heat ...
*Friday, March 1, 2013 at 8:27am by Brandi*

**Chemistry**

A student constructs a galvanic cell that has a strip of lead metal immersed in a solution of 0.1M Pb(NO3)2 as one half-cell and a strip of zinc metal immersed in a solution of 0.1M Zn(NO3)2 as the other half-cell. The measured cell potential is less than zero when the ...
*Tuesday, March 30, 2010 at 5:51pm by Mel*

**statistics**

A sample has a mean of M 40 If a score of X 55 is removed from the sample then the sample mean will increase
*Sunday, October 13, 2013 at 6:27pm by thcker*

**Chemistry**

118 g of a metal at 82.0°C are added to 50.0 g of water at 31.1°C. When the system reaches constant temperature, the temperature is 40.0°C. What is the specific heat of the metal? The specific heat of water is 4.184 J/g·°C.
*Monday, March 8, 2010 at 4:26pm by Tiffany*

**chemistry **

If 4.00 g of metal is plated in the voltaic cell (which contains Ag and Ni with the total potential of 2.98 V) , how much metal is plated in the electrolytic cell (contains Ag and Zn with the total of 1.98 V)? I have no idea how to do this! Help?
*Wednesday, March 7, 2012 at 7:32pm by Keisha*

**CHEMISTRY! Help?**

If 4.00 g of metal is plated in the voltaic cell (which contains Ag and Ni with the total potential of 2.98 V) , how much metal is plated in the electrolytic cell (contains Ag and Zn with the total of 1.98 V)? I have no idea how to do this! Help?
*Wednesday, March 7, 2012 at 7:46pm by Keisha*

**Chemistry **

If 4.00 g of metal is plated in the voltaic cell (which contains Ag and Ni with the total potential of 2.98 V) , how much metal is plated in the electrolytic cell (contains Ag and Zn with the total of 1.98 V)? I have no idea how to do this! Help?
*Wednesday, March 7, 2012 at 8:23pm by Keisha*

**physics**

A 10-g metal ball is moving to the left with a velocity of magnitude 0.4 m/s has a head-on, elastic collision with a larger 30-g metal ball moving to the right with a velocity of magnitude 0.2 m/s.
*Monday, January 13, 2014 at 12:21pm by killi*

**Chemistry**

Iron metal is produced from the ore iron(III) oxide by reacting the ore with gaseous carbon monoxide at high tempature to produce liquid iron metal and gaseous carbon dioxide. How do you balanced this equation for this reaction?
*Saturday, November 19, 2011 at 9:05pm by Nathan*

**business stat **

1. Suppose quality control inspectors at the coffee house chain take a sample of 100 pieces of this chocolate product from an incoming shipment. They find a sample average of 60% cacao with a standard deviation of 8%. What is the standard error of the sampling distribution of ...
*Monday, July 23, 2012 at 7:51pm by kristin *

**math**

Below is a sample space for a family with 3 children. BGG stands for the oldest child being a boy, the middle child a girl, and the youngest a girl. Use the sample space to answer the question: How many outcomes are in the sample space? Sample Space BBB BBG BGB BGG GBB GBG ...
*Thursday, April 5, 2012 at 5:28pm by Cheril*

**physics**

A metal rod and a metal ball were submerged in a pot of water that is heated from 30°C to 80°C. At the bottom of the pot, one of the ends of the rod touches the ball. After heating the water, the ball moved. What is the final Velocity?
*Thursday, June 30, 2011 at 6:44am by kim*

**college stat**

Use the graphic to show the sampling distributions of means for the sample from Prison A (n=82) and the sample from Prison B (n=37). Mark the expected value of the mean and the standard units. Shade in the critical zone for alpha = .05.Locate each sample mean after you have ...
*Tuesday, July 24, 2012 at 4:56pm by sammy*

**Chemistry**

A chemist heated a sample of steel wool in a burner flame exposed to oxygen in the air. He also heated a sample of steel wool in a container of nearly 100% oxygen. The steel wool sample in the container reacted faster than the other sample explain why
*Wednesday, March 17, 2010 at 9:13pm by Anonymous*

**science**

how far will 350 j raise a block weighing 7 N
*Tuesday, November 16, 2010 at 8:24pm by Myriel*

**physics**

how far will 490 J raise a block weighing 7 N?
*Monday, December 12, 2011 at 11:38pm by Melany*

**Chemistry**

According to the principle of electrical neutrality, a water sample must have the same number of anions and cations. Assuming that a water sample contains 40 mg/L of chloride, 100 mg/L sulfate, and 10 mg/L nitrate, estimate the maximum amount (in mg/L) of sodium that could be ...
*Wednesday, April 29, 2009 at 5:36pm by Caleb*

**Math**

Find the value of t for the difference between two means based on an assumption of normality and this information about two samples. (Use sample 1 - sample 2. Give your answer correct to two decimal places.) Sample Number Mean Std. Dev. 1 25 38.6 13.7 2 29 42.1 10.2
*Wednesday, June 26, 2013 at 11:21pm by Tracy *

**Math**

Find the value of t for the difference between two means based on an assumption of normality and this information about two samples. (Use sample 1 - sample 2. Give your answer correct to two decimal places.) Sample Number Mean Std. Dev. 1 25 38.6 13.7 2 29 42.1 10.2 .
*Thursday, June 27, 2013 at 5:52pm by Tracy *

**Algebra 1**

I am having trouble figuring out the final step when i get to multiply 5/9(1955.6) to get the set solution. Can you help. the question is below a metal stays solid at fahrenheit temperature below 1987.6. determine (in terms of an inequality) those celsius temperature for which...
*Tuesday, August 17, 2010 at 8:59pm by Kallie*

**college chemistry**

Consider the following metals. Metal Specific Heat copper 0.385 J/(g · °C) magnesium 1.02 J/(g · °C) mercury 0.138 J/(g · °C) silver 0.237 J/(g · °C) lead 0.129 J/(g · °C) If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial ...
*Thursday, December 2, 2010 at 4:39pm by Jake*

**math**

A water tank can be constructed with a metal top and two square ends that holds 16 cubic meter of water and requires 40 square meter of metal. find the dimensions of the water tank.
*Thursday, April 25, 2013 at 11:09am by kgosi*

**Physics**

120 grams of metal at 88 degree celcius is poured into a 70 grams isolated cup contains 250 grams of water at 16 degree celcius. The final temperature of the mixture is 17.5 degree celcius. Determine the specific heat capacity of the metal?
*Thursday, July 11, 2013 at 8:18am by vench*

**chemistry**

1. why is it necessary to use boiled and cooled water in the dilution of the carbonate sample? 2. an aliquot of the diluted sample is titrated with some standard HCl until near the equivalence point, then it is boiled for 2-3 minutes. why should we boil it? 3. any method to ...
*Thursday, January 6, 2011 at 12:02am by angelo*

**Chemistry**

I have a 2.5g sample in 12.5ml solution.I'm supposed to do a spike into this solution with the sample.If my standard concentration is 2000ppm, how much of this solution should I use such that I get 200ppm spike in sample?
*Tuesday, August 31, 2010 at 6:34pm by chloe*

**Physics - freezing tongue**

I have read through my chapter and still don't understand why your tongue sticks to a freezing metal pole. The question is, why doesn't your tongue freeze to wood at the same temp it will freeze to metal? I know that wood is a better insulator, but am not sure how that fits ...
*Wednesday, September 23, 2009 at 9:22am by Mary*

**chemistry**

a metal crystallizes in the face centered cubic crystal structure with a unit cell edge of 5.48 x10 power of -8 cm. the density of the metal is 6.90 g per cubic cm. a. what is the mass (g) of a single atom of this element. b. what is the atomic weight of the element (g per mol...
*Sunday, December 4, 2011 at 9:49pm by amanda*

**math**

a time capsule is in the shape of a cylinder with a hemisphere at each end. if the capsule is surrounded with a metal outer layer 4 cm thick as shown( there's a picture) then determine the volume of the metal outer layer. round your answer to the nearest cubic centimeter. the ...
*Tuesday, January 15, 2013 at 4:18pm by mary*

**Statistics**

SAT scores are normally distributed with a mean of 500 and a standard deviation of 100. Using the formula for ÏƒM, what will ÏƒM be when a. the sample size is 25 b. the sample size is 121, and c. the sample size is 400?
*Monday, November 18, 2013 at 8:04pm by Mikos*

**chemistry**

A metal pipeline is laid to carry oil 500 miles across desert.Temp @ night is 30 F: during day temp is 130 F? The linear coefficient of thermal expansion of metal is 0.000006, how much expansion and contraction along pipeline must the design engineer plan for.. a. 475 ft b. ...
*Tuesday, May 18, 2010 at 5:06pm by joe*

**Chemistry(Please help!!)**

For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...
*Sunday, October 23, 2011 at 6:19pm by Hannah*

**calculus**

A car[enter will be building a stained glass jewelry box. The frame of the box is to be built from a 48 inch stripe of metal which will be cut into 12 pieces. The 12 pieces are then soldered to form a rectangular box whose base is twice as long as it is wide. How should the ...
*Sunday, November 6, 2011 at 3:24pm by Demetra Mallios*

**physics**

a .300 kg piece of metal is heated to 88 degrees celsius and placed in a copper calorimeter with a mass .150 kg which contains .500kg which contains .500 L of water that are both initially at 12.6 degrees celcius. Over short period of time the mixture comes to an equilibrium ...
*Friday, April 19, 2013 at 12:42pm by Franky*

**Chemistry**

A sample of magnesium metal reacts with hydrochloric acid solution to produce magnsesium chloride solution and hydrogen gas. a)write a balanced chemical equation for this reaction and include phase designations. The phase designations would be s for solid, aq for aqueous, and ...
*Thursday, October 7, 2010 at 6:46pm by Anonymous*

**Chemistry**

A sample of magnesium metal reacts with hydrochloric acid solution to produce magnsesium chloride solution and hydrogen gas. a)write a balanced chemical equation for this reaction and include phase designations. The phase designations would be s for solid, aq for aqueous, and ...
*Thursday, October 7, 2010 at 8:07pm by Anonymous*

**physics **

The density of a sample of air is 1.235 kg/m3, and the bulk modulus is 1.42 · 105 N/m2. a) Find the speed of sound in the air sample. b) Find the temperature of the air sample. Give answer in °C. Do not enter unit. Yanlýþ. Denemeler
*Friday, April 1, 2011 at 9:38am by Urgent*

**Chemistry**

94.0 g of a metal at 88.0°C are added to 55.0 g of water at 26.0°C. When the system reaches constant temperature, the temperature is 39.3°C. What is the specific heat of the metal? The specific heat of water is 4.184 J/g·°C.
*Monday, March 8, 2010 at 4:28pm by Megan*

**Statistic**

birth weight of infants: a health care professional wishes to estimate the birth weights of infants. the researcher desires to be 99% confident that the true mean is within 2.5 ounces of the sample mean. the standard deviation of infant birth wieghts is known to be 7 ounces. ...
*Saturday, September 1, 2012 at 5:18pm by Anonymous*

**Statistic**

birth weight of infants: a health care professional wishes to estimate the birth weights of infants. the researcher desires to be 99% confident that the true mean is within 2.5 ounces of the sample mean. the standard deviation of infant birth wieghts is known to be 7 ounces. ...
*Saturday, September 1, 2012 at 5:18pm by Telicia*

**Chemistry**

silver ions in a solution of silver salts can be recovered by immersing copper metal in the solution. crystals of pure silver are deposited on the silver metal. design an experiment to determine the number of moles of silver atoms that form describe the procedure materials and...
*Wednesday, August 11, 2010 at 4:28am by annonomus*

**Chemistry**

silver ions in a solution of silver salts can be recovered by immersing copper metal in the solution. crystals of pure silver are deposited on the silver metal. design an experiment to determine the number of moles of silver atoms that form describe the procedure materials and...
*Wednesday, August 11, 2010 at 11:03pm by stacy*

**Chemistry**

silver ions in a solution of silver salts can be recovered by immersing copper metal in the solution. crystals of pure silver are deposited on the silver metal. design an experiment to determine the number of moles of silver atoms that form describe the procedure materials and...
*Wednesday, August 11, 2010 at 11:03pm by stacy*

**Physics (please check!)**

A positively charged light metal ball is suspended between two oppositely charged metal plates on an insulating thread as shown below. After being charged once, the plates are disconnected from the battery. Describe the behavior of the ball. Would the ball remain in the center?
*Monday, May 19, 2008 at 1:20pm by BAdams*

**statistics**

A student was asked to compute the mean and standard deviation for the following sample of n _ 5 scores: 81, 87, 89, 86, and 87. To simplify the arithmetic, the student first subtracted 80 points from each score to obtain a new sample consisting of 1, 7, 9, 6, and 7. The mean ...
*Wednesday, June 22, 2011 at 12:40am by Liz *

**Algebra **

A metal stays solid at fahrenheit temperatures below 1710.5 Determine (in terms of an inequakity) thoses celsius temperatures for which the metal stays solid. Use the formula F=9/5 C + 32. The solution set is {C< __ fahrenheit} 1710. Round to the nearest tenth.
*Friday, October 2, 2009 at 2:35pm by Sherry*

**Chemistry**

Identification of an unknown powdered metal by reaction with HCl: Why does the pH of the HCl solution initially increase very slowly when an unknown metal is first added to the acid solution, but gradually increase at a faster rate as the reaction proceeds to completion?
*Sunday, October 6, 2013 at 11:53pm by Ali*

**MATH STATS**

For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general population: (a) a sample of 10 with a mean of 44, (b) a sample of 1 with a mean of 48. The general population of ...
*Monday, July 4, 2011 at 2:06am by Vanessa*

**Statistics**

An IQ test is designed so that the mean is 100 and the standard deviation is 19 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 95% confidence that the sample mean is within ...
*Wednesday, February 12, 2014 at 10:12pm by Stephanie*

**chemistry**

As of May 17th 1213, the price of cobalt metal on the London Metal Exchange was $27500 per metric ton. One metric ton is defined as 1000Kg. Determine the price of cobalt in cents per atom.
*Sunday, May 26, 2013 at 11:25pm by Lulu*

**CHEM **

A metal, M, of atomic mass 91 amu reacts with fluorine to form a salt that can be represented as MFx. In order to determine x and therefore the formula of the salt, a boiling point elevation experiment is performed. A 9.05-g sample of the salt is dissolved in 100.0 g of water ...
*Sunday, July 8, 2012 at 9:12am by John*

**PHYSICS - PLEASE HELP**

Part A: A cardinal (Richmondena cardinalis) of mass 4.50×10^−2 kg and a baseball of mass 0.142 kg have the same kinetic energy. What is the ratio of the cardinal's magnitude p(c) of momentum to the magnitude p(b) of the baseball's momentum? Part B: A man weighing 650 N ...
*Wednesday, November 28, 2012 at 7:45am by Mary*

**PHYSICS - PLEASE HELP**

Part A: A cardinal (Richmondena cardinalis) of mass 4.50×10^−2 kg and a baseball of mass 0.142 kg have the same kinetic energy. What is the ratio of the cardinal's magnitude p(c) of momentum to the magnitude p(b) of the baseball's momentum? Part B: A man weighing 650 N ...
*Friday, November 30, 2012 at 11:16am by Anonymous*

**chemistry**

The reaction between potassium metal and chlorine gas is described by the following thermochemical equation K(s) + ½C_l2(g) = KCl(s) ÄH =–437 kJ mol–1 What will be the enthalpy change (to 2 significant figures) for the reaction when 6.0 g of potassium metal reacts with ...
*Tuesday, December 30, 2008 at 12:55pm by trigger*

**physics**

A 15 kg crate is held with a rope at the top of a metal ramp that has an incline of 25(degrees) with the horizontal. The rope breaks and slides down the ramp a distance of 5.50 meters before it hits the floor. If the coefficient of friction between the crate and the metal ramp...
*Thursday, February 24, 2011 at 10:18pm by taylor*

**physics**

how many cubic centimeters are in a block of brass weighing 34 grams?
*Sunday, January 9, 2011 at 10:19pm by izzy*

**Physics**

how do i find the volume of a block of platinum weighing 45.5 kilos
*Sunday, January 9, 2011 at 11:33pm by please help me*

**chemistry**

what is the volume (in ml)of a liquid(density=2.07 g/ml)weighing 130.grams?
*Thursday, September 22, 2011 at 9:52pm by ann*

**chemistry**

what is the volume (in ml)of a liquid(density=2.07 g/ml)weighing 130.grams?
*Thursday, September 22, 2011 at 10:17pm by victor*

**science**

how far will 350 jules raise a block weighing 7n
*Monday, March 12, 2012 at 9:04pm by christian*

**Chemistry**

which is more accurate direct weighting or weighing by difference?
*Tuesday, September 24, 2013 at 12:26pm by Justin*

**Science**

An object weighing 90 N has a volume of 45 mL and a mass of 9.0 g. What is its density? A. 0.10 g/mL B. 0.20 g/mL C. 5.0 g/mL d. 10 g/mL Please and Thank YOU
*Tuesday, November 26, 2013 at 11:19pm by Help Scienee*

**Physics**

Photons of energy 12eV are incident on a metal. It is found that current flows from the metal until a stopping potential of 8.0V is applied. What would happen if the wavelength of the incident photons was tripled? Would the energy be 4eV,so 12/3=4, and there will be no current...
*Monday, April 22, 2013 at 7:14pm by Sheila*

**Physics**

Photons of energy 12eV are incident on a metal. It is found that current flows from the metal until a stopping potential of 8.0V is applied. What would happen if the wavelength of the incident photons was tripled? Would the energy be 4eV,so 12/3=4, and there will be no current...
*Tuesday, April 23, 2013 at 4:53pm by Sheila*

**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**

calculate3 the concentrationof chloride in water sample Mw using this equation mol Ag+ = 1= MxVwx10-3 = MxVw mol Cl- 1 Mwx20.00x10-3 Mwx20 so M x Vw=Mw x20 or Mw= M x Vw 20 Mw= ? mol/L chloride in water sample= ? mmol/L Mw=? g/L chloride in water sample Mw=?ppm in water sample...
*Saturday, June 2, 2012 at 3:32am by lynda*

**statistics**

The scores of students on the ACT college entrance examination in a recent year had a normal distribution with a mean of 18.6 and a standard deviation of 5.9. A simple random sample of 50 students who took the exam is selected for study: A) What is the shape, mean, and ...
*Thursday, November 6, 2008 at 3:10pm by Marshall*

**Honors Chemistry**

I have to fill in the blanks of these questions with the elements H (hydrogen), Co (cobalt), Ga (gallium), and O (oxygen), but different sources are telling me different things: 7. Its most common oxidation state is -2 8. A metal with more than one oxidation state 9. Metal ...
*Monday, September 28, 2009 at 12:25am by Emily (different from one before me)*

**math check**

While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of one book. Her sample data can be summarized by the following. (Give your answers correct to two ...
*Friday, June 21, 2013 at 9:17pm by tom9*

**Statistics**

Kind attention Psydag: A random sample of size 20 from a normal population with sample mean 42 and sample standard deviation of 6 . To test the hypothesis the population mean 44 at 5% level of significance , find the p-value and comment Clarification: The sample size is 20 ...
*Friday, January 1, 2010 at 8:37am by Mrs. Lakshmi*

**chemistry**

A 94.7 g sample of silver (s= 0.237 J/(g x Degree C)), initially at 348.25 Degrees C , is added to an insulated vessel containing 143.6 g of water (s=4.18 J/(g x Degree C)), initially at 13.97 Degrees C. At equilibrium, the finial temperature of the metal-water mixture is 22....
*Wednesday, November 14, 2012 at 9:10pm by marcus *

**Chemistry**

1) A compound has the following percentages by mass: barium, 58.84%; sulfur, 13.74%; oxygen, 27.43%. Determine the empirical formula of the compound. 2) If a 1.271-g sample of aluminum metal is heated on a chlorine gas atmosphere, the mass of aluminum chloride produced is 6....
*Friday, December 30, 2011 at 11:07am by Natalie*

**Physics**

Part A: A cardinal (Richmondena cardinalis) of mass 4.50×10^−2 kg and a baseball of mass 0.142 kg have the same kinetic energy. What is the ratio of the cardinal's magnitude p(c) of momentum to the magnitude p(b) of the baseball's momentum? Part B: A man weighing 650 N ...
*Tuesday, November 27, 2012 at 6:42pm by Mary*

**Physics**

Part A: A cardinal (Richmondena cardinalis) of mass 4.50×10^−2 kg and a baseball of mass 0.142 kg have the same kinetic energy. What is the ratio of the cardinal's magnitude p(c) of momentum to the magnitude p(b) of the baseball's momentum? Part B: A man weighing 650 N ...
*Wednesday, November 28, 2012 at 5:16pm by M*

**statistics**

You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 5 and a population standard deviation 1 and a sample size of 4. Machine 2 has a sample mean of 8 and a population standard deviation of 2 with a sample size of 4. ...
*Monday, October 11, 2010 at 10:39pm by Anonymous*

**STAT**

You want to determine if your widgets from machine 1 are the same as machine 2. Machine 1 has a sample mean of 5 and a population standard deviation 2 and a sample size of 4. Machine 2 has a sample mean of 10 and a population standard deviation of 2 with a sample size of 64. ...
*Monday, October 7, 2013 at 1:43pm by Tammy*

**Chemistry**

30 grams of a metal at 100 degrees Celsius is placed in a calorimeter containing 100 mL of water at 21 degrees Celsius. After a few minutes, the temperature inside the calorimeter is 24 degrees Celsius. What is the specific heat of the metal?
*Thursday, December 20, 2012 at 7:35am by Syeph*

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