Tuesday

July 22, 2014

July 22, 2014

Total # Posts: 79

**math**

(3x10)+(5x9)

**math**

456736

**math**

write in words and in expanded form in two ways fractional and exponential 1.) 3.5968 2.)325.19217 3.)47.813

**math**

2.134

**math**

I am a decimal between 2 and 3. The digit in my thousandths place is the sum of the digits in my tenths and hundredths place. The digit in my tenths place is the difference of the digits in my thousandths and hundredths place. The digit in my hundreths place is one less than t...

**Math**

A certain bacteria doubles the number of its cells every 20 minutes. A scientist puts 50 Cells in a culture disk. How many cells will be in the culture disk in 2 hours?

**Math**

In a group of quarters and nickels, there are four more nickels than quarters. How many nickels and quarters are the if the coins are worth $2.30? Plsmshow the solution, thanks

**Pre algebra**

A number multiplied by itself and then by itself again gives -1,000. What is the number? Please show the solution step by step

**psychology**

need psy 302 help anybody out there?

**math**

suppose you won a contest at the start of 5th grade that deposited $3000 in an account that pays 5% annual interest compounded continuously. how much will you have in the account when you enter high school 4 years later? round to nearest dollar how much will be in the account ...

**physics**

A roller coaster travels 101 ft at an angle of 56.8 above the horizontal. How far does it move horizontally?

**Minoxidil**

So, I'm doing a research project for my chemistry class, and one of the parts that I have to answer is the chemical reaction of the substance that I'm researching. But there's a problem. I've searched every single website regarding minoxidil, but I cannot find ...

**math**

No we can' t divide 23 and 4

**math**

No we can' t divide 23 and 4

**math**

No we can' t divide 23 and 4

**4th grade Math Help**

No because 23 divide equal 69

**physics**

describe the force board experiment to show how to obtain the resultant of two non-parallel coplanar force acting at a point.four forces of magnitude 10N, 5N, 4N, AND 6N acts on an oblect in the direction north. West, east and south respectively.find the magnitude and directio...

**Chemistry**

Thank you so much DrBob222

**Chemistry**

Thank you so much DrBob222

**Chemistry**

Thank you so much DrBob222. You are the best

**Chemistry**

Can anyone help me with this question? Thanks

**Chemistry**

How much energy in KJ is release to form one mole of 123Sb from protons and neutrons if the atom has a mass of 122.90422 amu? Please remember to include the mass of electrons in calculations. Havent been taught this yet so a step by step walkthrough would help me immensely.Tha...

**College Chemistry**

How much time in years (assume a 365 day yr) would it take for a 1.6678g sample of 239Np to decay to a mass of 0.8671g if it has a half life of 2.030*10^5s

**College Chemistry**

I tried this but was told the answer was wrong.

**College Chemistry**

A rock containing 238U and 206Pb was examined to determine its appropriate age. The molar ratio of 206Pb to 238U was 0.1462. Assuming no lead was originally present and that all lead formed remained in the rock. What is the age of the rock in years? The half life of 238U is 4....

**chemistry**

Can the half cell electrochemistry experiment using a pH meter and aqueous solutions of Cu, Cu2+ and Ag and Ag+ be used to measure even lower concentrations, such as 10^-23 mol of Cu2+ or a single free copper ion in solution? Please explain.

**College Chemistry**

How many grams of Al would be deposited from an aqueous solution of Al3+ with a current of 1.430A after 5hrs of deposition.

**College Chemistry**

Thank you DrBob222

**College Chemistry**

If the voltage of the cell is -0.1288V at 25Celsius when [Pb2+]=0.1403M and the pressure of H2=1atm, what is the pH Pb(s)+2H+(aq)<-> Pb2+(aq) +H2(g) E0 = 0.1260V

**College Chemistry**

W = 2ⁿ , where n = number of molecules lnW = n • ln2 = 5.921 × 10¹⁴ ⇒ n = 8.542 × 10¹⁴ molecules

**College Chemistry**

I think this should be easy but im stuck. Please help: Suppose a compound could point in any of two directions in the solid and still have the same energy. How many molecules would there be if the total entropy of a solid sample of this compound was 8.174e-9J/K I used S= klnW ...

**Chemistry**

I figured it out. Had to find the molar solubility so square root of Ksp. Thanks

**Chemistry**

The free energy change for the dissolution of cuco3 at 25celsius is 56.246KJ/mol. What is the solubility of this compound. I used delta G/-RT = lnKsp but the answer i got was wrong.

**Chemistry**

Suppose a compound could point in any of two directions in the solid and still have the same energy. How many molecules would there be if the total entropy of a solid sample of this compound was 8.174e-9J/K I used S= klnW and got lnW = 5.92e14. How do i get the number of molec...

**Chemistry**

The vapor pressure of pure water at 90celsius is normally 525.8 but decreased 483mmHg upon addition of an unknown amount of KNO3 to 286.9g H2O at this temperature. how many grams KNO3 were added. ASSUME COMPLETE DISSOCIATION OF SOLUTE. Tried all solutions provided and still go...

**Chemistry**

What is the mole fraction of benzene C6H6 in the VAPOR PHASE from a solution consisting of a mixture of benzene and n-hexame ch3(ch2)4ch3 at 27celsius, if the total pressure above the solution is 135.2 torr? The vapor pressures of benzene and n-hexame at 27 celsius are 103 and...

**Chemistry**

What is the vapor pressure in Torr above a solution prepared by mixing 66.73g of benzene C6H6 with 63.26g toluene C6H5CH3 at 20 Celsius. The vapor pressure of pure benzene and toluene at 20celsius are 75 and 22 torr respectively. These compounds form nearly ideal solutions whe...

**Chemistry**

What is the mole fraction of methanol CH3OH, in the vapor phase from a solution consisting of a mixture of methanol and propanol CH3CH2CH2OH at 40celsius, if the total pressure above the solution is 131 torr? The vapor pressures of methanol and propanolare 303 and 44.60 torr r...

**Chemistry**

Thank you DrBob222.

**Chemistry**

How many grams of glycerin C3H8O3 must be dissolved in 375.9g of water at 100 degrees Celsius to reduce the pressure of water above the solution to 714.6mmHg. The solution is a non-volatile compound

**Chemistry**

12.821*1.604

**Chemistry**

What would Qc be if the volume of the container increased by a factor of 1.604 for this reaction SO2+Cl2<---> SO2CL2 kc = 12.821 at 373K

**Chemistry**

2.9*10-9/1.202*10-5 and find the square root of the number = 0.0155

**Chemistry**

What must be the concentration of F- to just start precipitation of SrF2 from a solution which is 1.202*10-5M i Sr(NO3)2? Ksp = 2.900*10-9

**Chemistry**

2.9*10-9/1.202*10-5 and find the square root of the number = 0.0155

**Chemistry**

What must be the concentration of F- to just start precipitation of SrF2 from a solution which is 1.202*10-5M i Sr(NO3)2? Ksp = 2.900*10-9

**Chemistry**

5.0*10^8= 0.0775/0.9331^6x x= 2.35e-10

**Chemistry**

What is the concentration of Ni2+ in 0.0775M Ni(NO3)2 and 1.3981M NH3

**Chemistry**

What is the solubility of Ca(OH)2 at a pH of 4.802 Ksp of Ca(OH)2 = 6.500*10-6

**Chemistry**

A buffer was made by mixing 0.1522 moles of HCO2H with 0.1832 moles LiHCO2- and diluting to exactly 1L. What will be the pH after addition of 10ml of 0.3657M NaOH to 50mL of the buffer. Ka(HCO2H) = 1.8*10-4

**Chemistry**

Calculate the[OH-] of a solution of 0.1861M CH3CH2CH2NH3CL if Kb= 5.1*10-4 for CH3CH2CH2NH2

**Chemistry**

How many moles of NaOBr- must be mixed with 0.1788 mole of HOBr and diluted to 1L to prepare a solution having a pH of 8.7043. Ka of HOBr = 2.0 * 10-9

**Chemistry**

Metal cations can act as lewis acids in water to produce an acidic solution even though the metal ion contains no hydrogen. Water hydrates the ions in solution and partial loss of electrons from water allows hydrogen ion to be lost What is the pH of a 0.1209M solution of Al3+ ...

**Chemistry**

I did an experiment using 20ml of 0.1M acetic acid and added 8ml of 0.1M NaOH. pH obtained after adding NaOH was 5.2. How do i calculate the mols of NaOH that reacted? mols of acetate formed, acetic acid initially present and acetic acid unreacted. Also how do i determine the ...

**Chemistry**

At 1473K the equilibrium constant for the reaction H2(g) + Cl2(g) <--------> 2HCl(g) Kc = 2.5*10^4. What would be the equilibrium concentration of HCL if the initial concentrations of H2 and Cl2 were 0.1840M and 0.1918M. I got 29.7 but was told it was wrong

**Chemistry**

ignore f's in the question

**Chemistry**

Reposting since it wasnt clear in the previous post S2O82-(aq) + 2I-(aq) ----------> 2SO42-(aq) + I2(aq) (I) Rate = k [S2O82-]x [I-]y Rate1 = k [S2O82-]x [I-]y Experiment data Experiment: 0.20M NaI,0.20M NaCl, 0.010M Na2S2O3,2% Starch,0.20M K2SO4, 0.20 M K2S2O8 Used 2ml = 2...

**Chemistry**

S2O82-(aq) + 2I-(aq) ----------> 2SO42-(aq) + I2(aq) (I) Rate = k [S2O82-]x [I-]y Rate1 = k [S2O82-]x [I-]y ƒ´ [S2O82ƒ{] Rate = ƒ{ƒn ------------- ƒ´ƒnt Experiment data Experiment: 0.20M NaI,0.20M NaCl, 0.010M Na2S2O3,2% Starch,0.20...

**Biology**

The trachea is ___________ to the lungs Toes are _______________to the shoulders Esophagus is _____________ to trachea Pinna is ______________ to tail Liver is ______________ to stomach Options are Anterior, Posterior, dorsal, ventral, lateral, median, superior, inferior, prox...

**Chemistry**

Why would an alcohol/water mixure not freeze at constant temperature.

**Chemistry**

Which of the following will have the smallest freezing point depression? 0.1158 m NaF 0.1158 m Na2SO4 0.1158 m K2SO4 0.1158 m Fe(NO3)3

**Chemistry**

The vapor pressure of pure water at 85 celsius is normally 433.6 mmHg but decrease to 393.8mmHg upon addition? of an unknown amount of ammoniu chloride NH4Cl to 162.2g of water at this temperature. How many grams of ammonium chloride were added assuming complete dissociation o...

**Chemistry**

How many grams of carbon tetrachloride CCL4 must be mixed with 35.96g of ethyl acetate CH3COOCH2CH3 at 50? celsius to produce a solution with a vapor pressure above the solution of 291.8 torr. The vapor pressure of pure carbon tetrachloride and ethyl acetate at 50 celsius are ...

**Chemistry**

What is the mole fraction of methyl n-butyrate CH3(Ch2)2COOCH3 in the vapor phase of a solution consisting of? a mixture of methyl n-butyrate and ethyl acetate CH3COOCH2CH3 at 50 Celsius if the total pressure above the solution is 192.5 torr. The vapor pressure of methyl n-but...

**chemistry**

Consider the hypothetical elements X and Y. Suppose the enthalpy of formation for the compound XY is -336 kJ/mol, the bond energy for X2 is 414 kJ/mol, and the bond energy for Y2 is 159 kJ/mol. Estimate the XY bond energy in units of kJ/mol.

**Chemistry**

189 he?

**Chemistry**

The density of a solution of 3.69g KBr in 21.70g H2O is 1.11g/mL. What is the %w/v of KBr in the solution?

**Chemistry**

The density of a solution of 3.69g KBr in 21.70g H2O is 1.11g/mL. What is the molarity of KBr in the solution.

**Chemistry**

When 24.0g og glucose(a nonelectrolyte) are dissolved in 500g of water, the solution has a freezing point of -0.47C. What is the molar mass of glucose according to yhe data?Kf of water is 1.86C/m.

**physics**

Which is true as one gets closer to the center of the earth? a. The person’s weight increases b. The person’s weight decreases c. The person’s weight remains the same d. The person’s mass changes e. A new dimension is discovered

**physics**

In a hydrogen atom, if the radius of the orbit of the electron is doubled, then its energy will ... a)Decrease by a factor of 2 b)Remain the same c)Increase by a factor of 2 d)Actually, it is not possible for the radius of the orbit to double e)Increase or decrease by a facto...

**physics**

An ultrasonic beam reflects off a tumor in an organ at an angle of 50 with a shift L = 7 cm. If the speed of the wave is 26 % less in the organ than in the medium above, determine the depth of the tumor below the organ's surface

**physics**

If i take the inverse of a value, what happens to its uncertainty? For example, if I have C +/- deltC and then i do 1/C. What happens to delta C? Thank you

**physics**

Given a square of sidelength a = 5 cm. We place a charged particle at each corner, three of them carry + 2 nC of charge and one carries the same amount of negative charge. What is the magnitude of the electric field at the center of the square? I dont know how to start this pr...

**Chemistry**

At what initial concentration would a solution of acetic acid (ka=1.8x10^-5) be 2% ionized? I am stuck. Thanks -J

**Chemistry! Please Help!**

What mass of propanoic acid, CH3CH2COOH, pKa= 4.87, should be dissolved in water to 2.00L volume in order to produce a pH of 2.50? THANKS! -J

**Chemistry!!**

At what initial concentration would a solution of acetic acid (ka=1.8x10^-5) be 2% ionized? THANKS! -J

**Chemistry!! Please Help!**

What mass of propanoic acid, CH3CH2COOH, pKa= 4.87, should be dissolved in water to 2.00L volume in order to produce a pH of 2.50? THANKS! -J

**english**

who is the eponymous hero in the books written by kevin crossley-holland This site will tell you about the book trilogy and give you the name of the hero. http://en.wikipedia.org/wiki/The_Seeing_Stone

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