# Posts by Lauren

Total # Posts: 1,848

Chemistry
I got 88.9 L/(mol*s)

Chemistry
In a kinetic study of the reaction 2NO(g) + O2 --> 2NO2(g) the following data were obtained fro the initial rates if disapperance of NO: Initial concentraition NO O2 Inital Rate NO exp 1. 0.0125M 0.0253M 0.0281 M/s exp 2. 0.0250M 0.0253M 0.0112 M/s exp 3. 0.0125M 0.0506M 0....

Chemistry
Iron (II) ion is oxidized by hydrogen peroxide in acidic solution. H2O2(aq) + 2Fe2+(aq) + 2H+(aq) ---> 2Fe3+(aq) + 2H2O (l) the rate law is k[H2O2][Fe2+] what is the order with respect to each reactant ? what is the overall order

Chemistry
For the reaction of nitric oxide, NO with chlorine Cl2 2NO(g) + Cl2(g)--> 2NOCl(g) the observed rate law is k[NO]^2 [Cl2] what is the reaction order with respect to nirtic oxide? with respect to Cl2? What is the overal order? how

Chemistry
Nitrogen Dioxide NO2 decomposes upon heating to form nitric oxide and oxygen according to the following equation: 2NO2(g) --> 2NO(g) + O2(g) At the beginning of an experiment the concentration of nitrogen dioxide in a reaction vessel was 0.113 mol/L. After 60.0 s, the ...

Chemistry
so it would be .00948/240 right

Chemistry
Iron(III) chloride is reduced by tin(II) chloride. the concentration of Fe3+ ion at the beginning of an experiment was 0.03586M. After 4.00 min it was 0.02638M. What is the average rate of reaction of FeCl3 in this time interval? Can someone help me figure this one out please

Chemistry
so change every I2 to H2

Chemistry
for the reaction of hydrogen with iodine H2(g) + I2(g) --> 2HI(g) relate the rate of disappearance of hydrogen gas to the rate of formation of hydrogen iodide. and my answer is: rate formation of HI= delta [HI]/delta t and the rate of reaction of I2 = delta [I2]/ delta t to...

Chemistry
To obtain the rate of the reaction 3I-(aq) + H3AsO4(aq) + 2H+(aq) --> I3-(aq) + H3AsO3(aq) + H2O (l) I got that the rate is 1/3 delta [I-]/ delta t = delta [H3AsO4]/ delta t is this correct

statistics
Professor Smith conducted a class exercise in which students ran a computer program to generate random samples from a population that had a mean of 50 and a standard deviation of 9mm. Each of Smith's students took a random sample of size n and calculated the sample mean. ...

statistics
An important indicator of lung function is forced expiratory volume(FEV), which is the volume of air that a person can expire in one second. Dr. Jones plans to measure FEv in a random sample of n young women from a certain population, and to use the sample mean as an estimate ...

i'm french can u help me about english??
i believe the answer is b

Physics
the 65 does not represent the degrees. . .that is why i am so confused on this problem

Physics
At time t = 0s, a puck is sliding on a horizontal table with a velocity 3.00 m/s, 65.0 above the +x axis. As the puck slides, a constant acceleration acts on it that was the following components: ax = 0.460m/s2 and ay = 0.980m/s2. what is the velocity of the puck at time t = 1...

Chemistry
is it 60 g of urea for the molar mass and then take the 0.00457/60 and get grams ???

Chemistry
Urea (NH2)2CO is dissolved in 100.0 g of water. The solution freezes at -0.085 degrees C. how many grams of urea were dissolved to make this solution. delta T = Kf*molality Plug in 0.085 for delta T, I assume you know Kf for water, calculate molality. Then molality x kg ...

Chemistry
Aluminum hydroxide forms a positively charged sol. Which of the following ionic substances should be most effective in coagulating the sol? NaCl CaCl2 Fe2(SO4)3 K3PO4 The idea behind coagulating sols is to use those salts that have the highest + and - charges and the most ions...

Chemistry
so they are the same and both dissolve in ethanol or acetic acid dissolves in ethanol because they are small molecules

Chemistry
Indicate which is more soluble in ethonal: acetic acid CH3COOH or stearic acid C17H35COOH I think acetic acid maybe more soluble but I don't know why

Chemisty
Aluminum hydroxide forms a positively charged sol. Which of the following ionic substances should be most effective in coagulating the sol? NaCl CaCl2 Fe2(SO4)3 K3PO4 The idea behind coagulating sols is to use those salts that have the highest + and - charges and the most ions...

Chemisty
Aluminum hydroxide forms a positively charged sol. Which of the following ionic substances should be most effective in coagulating the sol? NaCl CaCl2 Fe2(SO4)3 K3PO4

Chemistry
A solution contains 0.0653g of compound in 8.31g of ethanol. The molarity of the solution is 0.0368m. Calculate the molecular weight of the compound For Further Reading Chemisty - drbob222, Thursday, February 7, 2008 at 9:40pm The molarity of the solution can't be 0.0368 m...

Chemistry
so it would be 0.085 degrees C = 1.86 C/m (0.1 kg/60 g of (NH2)2CO

Chemistry
wait no its 1.858 Kf(degress C/m)

Chemistry
Urea (NH2)2CO is dissolved in 100.0 g of water. The solution freezes at -0.085 degrees C. how many grams of urea were dissolved to make this solution. delta T = Kf*molality Plug in 0.085 for delta T, I assume you know Kf for water, calculate molality. Then molality x kg ...

Chemistry
well actually i double clicked the submit button and it posted it twice... sorry

Chemistry
Urea (NH2)2CO is dissolved in 100.0 g of water. The solution freezes at -0.085 degrees C. how many grams of urea were dissolved to make this solution. delta T = Kf*molality Plug in 0.085 for delta T, I assume you know Kf for water, calculate molality. Then molality x kg ...

Chem
well you have more 00.00 sig figs than 3 so i would put it as 4 sig figs not 3

Math
38 x 7 = 266

Chemisty
sorry my fault it is suppose to be molality

Chemisty
A solution contains 0.0653g of compound in 8.31g of ethanol. The molarity of the solution is 0.0368m. Calculate the molecular weight of the compound

Chemistry
Urea (NH2)2CO is dissolved in 100.0 g of water. The solution freezes at -0.085 degrees C. how many grams of urea were dissolved to make this solution.

Chemistry
A solution was prepared by dissolving 0.817g of sulfur S8, in 100.0g of acetic acid, HC2H3O2. Calculate the freezing point and boiling point of the solution

Chemistry
92.40 [mmHg]

Chemistry
What is the vapor pressure at 23 degree C of a solution of 1.20g of naphthalene, C10H8 in 25.6 g of benzene, C6H6? The vapor pressure of naphthalene can be neglected. Calculate the vapor-pressure lowering the solution

Chemistry
Citric acid H3C6H5O7, occurs in plants. Lemons contain 5% to 8% citric acid by mass. The acid is added to beverages and candy. An aqueous solution is 0.688m citric acid. The density is 1.049 g/ml. What is the molar concentration?

Chemistry
Citric acid H3C6H5O7, occurs in plants. Lemons contain 5% to 8% citric acid by mass. The acid is added to beverages and candy. An aqueous solution is 0.688m citric acid. The density is 1.049 g/ml. What is the molar concentration?

Chemistry
Concentrated aqueous ammonia contains 1.00 mol NH3 dissolved in 2.44 mol H20. What is the mole fraction of NH3 in concentrated aqueous ammonia? What is the molal concentration of NH3

algebra
i think its 216

algebra
alright thanks anyway

algebra
but then the directions say variable substitution

algebra
so is that it?? simple as that?

algebra
so then its x^2-6 =0 and ^2-3=0 and the don't i put the root sign over the x^2 to get rid of the x^2? and then i end up with x + or - the suare root of 6 = 0 or is that wrong??

algebra
is it (x^2 - 6) (x^2 - 3) ??

algebra
use variable substitution and factoring to find all of the roots of each equation. x^4-9x^2+18=0 how do you do this??

Chemistry
ok i know how to figure out the 2nd equation 45.0g CHCl3(1 mols/118gCHCl3)=.381 mols CHCl3 but how do you get molarity. with kg solvent

Chemistry
Caffeine C8H10N4O2, is a stimulant found in a tea and coffee. A sample of the substance was dissolved in 45.0g of choloroform CHCl3 to give a 0.0946m solution. How many grams of caffine were in the sample. m = molality

Chemistry
29.575/455*100=6.5% Yay :)

Chemistry
so then i did it wrong... :( is it 142g for the Na2SO4 that needs to be put into there

Chemistry
How would you prepare 455 g of aqueous solution that is 6.50% sodium sulfate Na2SO4 by mass? percent by mass = grams/100 g solution. X grams/455 = 0.065 solve for X. Subtract 455-X to calculate how much water must be added. ok i got -454.935 is this right

Chemistry
23.0769 right

Chemistry
so for this part (g Na2SO4/g solution) = (1.50 g Na2SO4/x g solution). it would be (g Na2SO4/ .065 g solution = 1.50 g Na2SO4/ x .065 g solution ) or did i miss place them

Chemistry
What mass of solution containing 6.50% sodium sulfate N2SO4 by mass contains 1.50g Na2SO4 Set up a proportion. (g Na2SO4/g solution) = (1.50 g Na2SO4/x g solution). Solve for x. Check my work. how do you fine g solution

Chemistry
Determine the mass of the element. What element is it? what is the molar volume of the metal in cubic centimeters(avogadro's number should be used for this problem -1cm=10^7 nm)

Chemistry
What is the molar volume of the metal in cubic centimeters? (Avogadro's number should be used for this problem ------ 1 cm = 10^7 nm what is the molar volume of the metal in cubic centimeters(avogadro's number should be used for this problem -1cm=10^7 nm)

Chemistry
The question is what is the volume of the unit cell? I don't understand how to get the volume of it

Chemistry
what is the volume of the unit cell? A metal crystallizes in a face-centered cubic lattice. The radius of the atom is 0.197 nm. The density of the element is 1.54 g/cm^3

Chemistry
NaCl crystallizes in face-centered cubic cell. what is the total number of ions(Na+ ions and Cr- ions) that lie withing a unit cell of NaCl? 2 4 8 6 5

Chemistry
What portion of the volume of each atom or ion on the face of a unit cell is actually within the unit cell 1/2 1/4 3/4 all of it none of it

Chemistry
The unit cell with all sides the same length and all angles equal to 90 degrees that has lattice points only at the corners is called monoclinic body-centered cubic primative cubic face-centered cubic spherical cubic

Chemistry
Determine the mass of the element? what element is it? Ca Ag Ti Mg Al

Chemistry
what is the molar volume of the metal in cubic centimeters(avogadro's number should be used for this problem -1cm=10^7 nm)

Chemistry
what is the volume of the unit cell

Chemistry
What mass of solution containing 6.50% sodium sulfate N2SO4 by mass contains 1.50g Na2SO4

Chemistry
How would you prepare 455 g of aqueous solution that is 6.50% sodium sulfate Na2SO4 by mass?

Chemistry
Indicate which is more soluble in ethanol? C2H5OH, acetic acid, CH3COOH, or stearic acid C17H35COOH.

Chemistry
People have proposed towing icebergs to arid parts of the earth as a way to deliver freshwater. Explain why icebergs do not contain salts although they are formed by the freezing of ocean water (i.e saltwater)

Chemistry
A tank of gas at 21 degrees C has a pressure of 1.0 atm. Using the data in the table answer the following questions. Explain your answers A. If the tank contains carbon tetrafluoride, CF4 is the liquid state also present? B. If the tank contains butane, C4H10 is the liquid ...

Chemistry
A quantity of ice at 0.0 degrees C was added to 33.6 of water at 21.0 degree C to give water at 0.0 degrees C. How much ice was added? The heat of fusion of water is 6.01 kJ/mol and the specific heat is 4.18 J/(g * degrees C) q = mass x specific heat x delta T? q = mass x heat...

Chemistry
A quantity of ice at 0.0 degrees C was added to 33.6 of water at 21.0 degree C to give water at 0.0 degrees C. How much ice was added? The heat of fusion of water is 6.01 kJ/mol and the specific heat is 4.18 J/(g * degrees C) q = mass x specific heat x delta T? q = mass x heat...

Chemistry
Methanol, CH3OH a colorless voltile liquid was formerly known as wood alcohol. It boils at 65 degrees C and has a heat of vaporization of 37.4 kJ/mol. What is its vapor pressure at 22.0 degrees C?

algebra
-8+3 = -5 x-5<11 +5 +5 X< 16

Chemistry
Snow forms in the upper atmosphere in a cold aid mass that is supersatuated with water vapor. When the snow later falls through a lower, warm air mass, rain forms. When atomic weight is 63.5 amu. Calculate the edge length of the unit cell.

Chemistry
On the basis of the description given classify each of the following solids as molecular, metallic, ionic, or covalent network. Explain why? A. a lustrous, yellow solid that conducts electricity B. a hard, black solid melting at 2350 degrees C to give a nonconducting liquid C...

Chemistry
well all it asks is name the types of solid it forms and those four our the types of solids. so like LiCl you said it was an ionic compound so it might be ab ionic solid and so on

Chemistry
Classify each of the following by the type of solid if forms: a. LiCl b. BaCl2 c. BCl3 d. CCl4 e. NCl3 I have four different types of solids to guess from like Metallic solid, ionic solid, molecular solid, covalent network solid and i don't know which goes with what element

Chemistry
Describe the formation of hydrogen bonds in a hydrogen peroxide, H2O2. Represent possible hydrogen bonding structures in hydrogen peroxide by using structural formulas and the conventional notation for a hydrogen bond.

Chemistry
Snow forms in the upper atmosphere in a cold aid mass that is supersatuated with water vapor. When the snow later falls through a lower, warm air mass, rain forms. When atomic weight is 63.5 amu. Calculate the edge length of the unit cell.

Chemistry
On the basis of the description given classify each of the following solids as molecular, metallic, ionic, or covalent network. Explain why? A. a lustrous, yellow solid that conducts electricity B. a hard, black solid melting at 2350 degrees C to give a nonconducting liquid C...

Chemistry
Sorry I clicked to fast but that is the question and I have four different types of solids to guess from Like Metallic solid, ionic solid, molecular solid, covalent network solid and i don't know which goes with what element

Chemistry
Which of the following do you expect to be molecular solids? A. sodium hydroxide NaOH B. Solid Ethane C2H6 C. Nickel, Ni D. Solid Silane SiH4

Chemistry
I didn't write I cant find it someone else did being stupid and putting my name down as a reply

Chemistry
Can't find it.

Chemistry
Classify each of the following by the type of solid if forms: a. LiCl b. BaCl2 c. BCl3 d. CCl4 e. NCl3

Chemistry
Predict the order of increasing vapor pressure at a given temperature for the following compounds: CH3CH2CH2CH2OH HOCH2CH2CH2OH CH3CH2OCH2CH3

Chemistry
which of the following compounds would you expect to exhibit only London forces? CCL4 CCLH CaI2 PCl5

Chemistry
A tank of gas at 21 degrees C has a pressure of 1.0 atm. Using the data in the table answer the following questions. Explain your answers A. If the tank contains carbon tetrafluoride, CF4 is the liquid state also present? B. If the tank contains butane, C4H10 is the liquid ...

Chemistry
Methanol, CH3OH a colorless, volatile liquid was formely known as wood alcohol. It boils at 65.0 degrees C and has a heat vaporization of 37.4 kJ/mol. What is its vapor pressure at 22.0 degrees C ?

Chemistry
A quantity of ice at 0.0 degrees C was added to 33.6 of water at 21.0 degree C to give water at 0.0 degrees C. How much ice was added? The heat of fusion of water is 6.01 kJ/mol and the specific heat is 4.18 J/(g * degrees C)

Chemistry
Liquid Butane, C4H10, is stored in cylinders to be used as a fuel. Suppose 39.3g of butane gas is removed from a cylinder. How much heat must be provided to vaporize this much gas? The heat of vaporization of butane is 21.3 kJ/mol.

Chemistry
Liquid Butane, C4H10, is stored in cylinders to be used as a fuel. Suppose 39.3g of butane gas is removed from a cylinder. How much heat must be provided to vaporize this much gas? The heat of vaporization of butane is 21.3 kJ/mol.

Chemistry
A 35.8f sample of cadminum metal was melted by an electric heater 4.66 J/s of heat. If it took 6.92 min from the time the metal began to melt until it was completely melted, what is the heat of fusion per mole of cadminum?

In a world without trade, what would American consumers have to pay for logitech's products?

Chemistry
Phase diagrams- Explain how the density of the solid and liquid phase would compare.

Chemistry
I think this might be right...adjusting the volume for temperature. 273K + 23K= 296K The two possible temperature ratio would be 296K/273K or 273K/296K. I chose the second one. 57.6 ml(273K)/296K answer: 53.1 ml

Chemistry
A eudiometer contains 65.0 ml sample of gas collected by the diplacement of water. The water levels inside and outside the eudiometer are the same. The atmospheric pressure is 92.5 kPa and the temperture is 23 degrees. What volume will the dry gas occupy at STP? The vapor ...

Chemistry
A pocket of gas is discovered in a deep drilling operation. The gas has a temperature of 480c and is at a pressure of 12.8 atm. What volume of gas is required to provide 18.0 L of gas at the surface where the conditions are 22 C and 1.00 atm?

Chemistry
Answer check: Define a catalyst and explain a catalyst's role in a chemical reaction. A catalyst is a substance that speeds a chemical reaction without being permanently changed itself. It works by providing a convenient surface for the reaction to occur. The reacting ...

English
Hi, I need to know the background on the literay term: interjection. I have the definition and examples of it, but I can't seem to find any history on it. Help would be appreciated. Thank you so much!