# Posts by K

Total # Posts: 981

**CHEM**

The mass of an electron is 9.11*10^-31kg. If the de Broglie wavelength for an electron in a hydrogen atom is 3.31*10^-10m, how fast is the electron moving relative to the speed of light? The speed of light is 3.00*10^8m/s. Express your answer numerically as a percentage of the...

**economics**

Where does Bexar County rank among texas counties in per capita income? <br><br> Where does Cameron County rank among texas counties in per capita income? <br><br> what was the inflation rate in hungary in 1945-1946?

**Lunch**

take some almonds as a snack throughout the day. As for lunch, take a balanced lunch = with some fruit for dessert, ex.an apple or pear or something of the sort. Main course could be something like a turkey sandwich on whole wheat, or on a whole wheat begal if you so choose. ...

**CHEM**

i mean... 0.574L didn't work.

**CHEM**

Butane, C4H10, is a component of natural gas that is used as fuel for cigarette lighters. The balanced equation of the complete combustion of butane is: 2C4H10(g) + 13O2(g)->8CO2(g) + 10H2O(l) At 1.00atm and 23*C , how many liters of carbon dioxide are formed by the ...

**CHEM**

I worked the info above out &, yes, your thinking was indeed correct. Thank you heeps.

**CHEM**

I tired 7.79g of He added & it told me this: This number looks like the final mass of He multiplied by 2. Instead, find the difference between the final and initial masses.

**CHEM**

A cylinder with a movable piston contains 2.00g of helium, He, at room temperature. More helium was added to the cylinder and the volume was adjusted so that the gas pressure remained the same. How many grams of helium were added to the cylinder if the volume was changed from ...

**CHEM**

well...I managed to use the correct equation: M=mRt/PV...& the answer came to Ar. Thank you very much!!

**CHEM**

the only prob left is: do I just add the variables? or which ones do I take into account? PV=nRT n=RT/PV...or should I be using: M=mRT/PV???

**CHEM**

#2= 1.61atm:)

**CHEM**

ok...I tried my answer...I got the first part correct..it was actually 0.455atm.

**CHEM**

for Part 1: would the P2 just be 0.454 atm then? I went: P1*V1=P2*V2 then: P2=P1*V1/V2? So...1atm*1L/2.20L = P2= 0.454atm??

**CHEM**

A) a picture shows a container that is sealed at the top by a movable piston. Inside the container is a ideal gas at 1.00atm , 20.0 *C, and 1.00L. (The pic is of a 2L container which has a piston pushed downward to the 1L level. Under the piston, under the 1L mark, is a sample...

**CHEM**

thank you!

**CHEM**

Thank you muchly!! (the questions are just from an old MT that we were to go over to study for the real MT this coming Sat.)

**CHEM**

so for #14 I got: 4mols #16: 1.0mL #17...the other two choices were b-0.1MCH3COOH & then d) both A&B, that's why I didn't bother putting them in, considering b is not an electrolyte. #25: b- HCl? #2, about Av's #...the options were: a)the # of Hydrogen atom in ...

**CHEM**

I was just wondering if someone would be able to critique my answers for the following Chem questions? they range from pretty basic to a bit more... 2)which of the following is the definition of the value of Avogadro's constant: b) the # of Carbon atoms in exactly 12g of ...

**ECON-HELP!!**

% Change in M + % Change in V = % Change in P + % Change in Y. i.e, % Change in P = % Change in M + % Change in V – % Change in Y. % Change in P = 14% + 0% – 5% = 9%. % Change in P is the inflation rate π. From the Fisher equation, we have i = r + π, i is ...

**Science**

What would be the likely function of a plant cell containing many chloroplasts?

**CHEM**

Help on part "c": The forensic technician at a crime scene has just prepared a luminol stock solution by adding 19.0g of luminol into a total volume of 75.0mL of H2O. a)What is the molarity of the stock solution of luminol? answer I got: molarity of luminol solution...

**CHEM**

this answer, 83.9mL worked...thank you for the guidance.

**CHEM**

Help on part "c": The forensic technician at a crime scene has just prepared a luminol stock solution by adding 19.0g of luminol into a total volume of 75.0mL of H2O. a)What is the molarity of the stock solution of luminol? anwer I got: molarity of luminol solution...

**CHEM-last part prob.**

(oh...slightly dislexic...yes...I meant 0.225 moles, that would have helped if I had noticed before & typed it in correctly.)

**CHEM-last part prob.**

ok...so I shouldn't have multiplied through by 2. That makes a lot more sense. Thank you, yet again, and it came out alright.

**CHEM-last part prob.**

I tried this answer & it was incorrect.

**CHEM-last part prob.**

Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s) + 3Cl2(g) -> 2AlCl3(s) You are given 19.0g of aluminum and 24.0g of chlorine gas. a)If you had excess chlorine, how many moles of of aluminum chloride could be produced from 19.0g...

**CHEM**

I kept trying it, via comparing it to a, & finally did come up with 0.255mol AlCl3...I had just gotten the question incorrect,somehow, 4x...so I had to ask. Thank you for your patience with me. I will be looking into getting a tutor shortly.

**CHEM**

Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s) + 3Cl2(g) -> 2AlCl3(s) You are given 19.0g of aluminum and 24.0g of chlorine gas. a)If you had excess chlorine, how many moles of of aluminum chloride could be produced from 19.0g...

**CHEM**

it worked out beautifully. Thank you!

**CHEM**

My balanced equation is: a) 2C8H18(g) + 25O2(g) -> 16CO2(g) + 18H2O(g) b) 0.290 mol of octane is allowed to react with 0.670mol of oxygen. Which is the limiting reactant? (((Which I found Oxygen to be the limiting reactant.))) I do not understant how to work out "c&...

**CHEM**

THIS time I got it correct! answer = 5.13x10^-19 molecules! THANK YOU soooo much!! I only had 2 attempts remaining!

**CHEM**

How many molecules of ammonia are produced from: 2.58x10^-4g of Hydrogen? My balanced equation: 3H2 + N2 = 2NH3 I worked this question as: mol of H = 2.58x10^-4g/1.00794g/mol= 2.559676x10^-4 mol mol of NH3 produced = 2x2.559676x10^-4mol/3mol NH3 = 1.706450701x10^-4 Molecules...

**CHEM**

Calculate the mass (in grams) of the product formed when 10.1g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant. 2K(s) + __Cl2(g)__ -> 2KCl(s) I cannot get the correct answer.

**CHEM**

A scientist wants to make a solution of tribasic sodium phosphate,Na3PO4 , for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 575mL of a solution that has a concentration of Na^+ ions of 1.40 M? Answer: mass of Na3PO4 = _____ How is this question ...

**CHEM**

My question doesn't have to be answered. I figured out what they were asking and got it correct.

**CHEM**

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4Al(s) + 3O2(g) -> 2Al2O3(s) 4mol Al, 2.6mol O2? a) 4mol Al, b) 2.6mol O2. I seriously have no idea what they are asking! What do you do with the 4mol Al & 2.6mol O2...

**CHEM**

does this sound correct? 8.00X10^-4 kg?

**CHEM**

I am still not quite grasping how to complete this problem: Posted by K on Sunday, October 14, 2007 at 6:43pm. Many home barbeques are fueled with propane gas C3H8. What mass of carbon dioxide (in kg) is produced upon the complete combustion of 18.9L of propane (approximate ...

**CHEM**

Many home barbeques are fueled with propane gas C3H8. What mass of carbon dioxide (in kg) is produced upon the complete combustion of 18.9L of propane (approximate contents of one 5-gallon tank)? Assume that the density of the liquid propane in the tank is 0.621g/ml. How do I ...

**banking**

two words: aehoumncrrusse

**chem**

A&B worked...thank you

**chem**

it has to be choose all that are possiblities. Do you think that a and b then are the best choices? E and G def. are not, agreed.

**chem**

A blood sample contains several different types of cells, each of which contains different combinations of specific ions and molecules. The cells are suspended in water, and the water also contains many molecules and ions. Which term or terms could be used to describe this ...

**English**

thank you so much!!! you really helped!

**English**

What's the difference between the following sentences: "he looks happy." "he looks like he's happy." "he seems happy."

**maths**

how wod i solve the following two eqautions? either exactly or to 3 significant a)2^x = 5 b)3^x+1 = 7 i know a) is 2.32 and b) is 0.771 but i don't know how to show it out step by step in how i worked it out . can sum1 plz help me You have to use logs, and learn how to do ...

**art**

why do artist use parallel lines that do intersect?? Thank you for using the Jiskha Homework Help Forum. Here is a definition of parallel: extending in the same direction, everywhere equidistant, and not meeting Just what art are you referring to? Parallel lines do not ...

**lines**

] A printed capital letter names a:

**geometery**

[1.04] If B is between A and C, AB=2x-1, BC=3x+5 and AC=24, what is the value of x? Segment A C contains point B. *A=======B======*C If AC = 24; AB = 2x-1 and BC = 3x+5, then AB + BC = AC. Solve for X. Post your work if you get stuck. (2x -1) + (3x +5) = 24 5x +4 = 24 5x = 20 ...

**maths**

A town planner is using a map of a town centre with a scale of 1: 1250 A path in the town is 8cm long on the map. How long is the path in the town? Give your answers in metres. how do i work this out?? set up the proportion: 1/1250 = 8/x x=1250*8 cm = 10000 cm =100 m

**science**

The specific heat capacity of the lava is 1600 J kg -1 degrees Celsius -1 . When all the erupted lava cools from the eruption temperature of 1050 degrees Celsius to 15 degrees Celsius, the heat released is 2 x 10 15 J. Calculate a value for the total mass of lava that erupted...

**Chemistry**

Even though it's been years, 8.58 x 10^-4 M would be the standardized solution of KMnO4. This is usually given by the lab instructor at the beginning of the experiment.

**maths**

The head of an industrial machine moves in a straight line horizontally backwards and forwards from a central position. The movement can be modelled using the sine wave d = 80 sin ( pie t), where d is the horizontal distance (in cm) from the central starting position, and t is...

**maths**

The head of an industrial machine moves in a straight line horizontally backwards and forwards from a central position. The movement can be modelled using the sine wave d = 80 sin ( pie t), where d is the horizontal distance (in cm) from the central starting position, and t is...

**Science**

As each organism eats each other they transfer energy!! I'm doing the same thing lol

**science**

hi, could any1 tell me in basic words on "the environment and process of formation of schist and sandstone?? Since this is not my area of expertise, I searched Google under the key words "'formation process' schist sandstone" to get these possible ...

**maths**

The head of an industrial machine moves in a straight line horizontally backwards and forwards from a central position. The movement can be modelled using the sine wave d = 80 sin ( pie t), where d is the horizontal distance (in cm) from the central starting position, and t is...

**calculus**

323

**Economics**

What changes, if any, to the current condition of these tools would you make at the next meeting of the Federal Reserve? Explain why and the benefits/drawbacks of this strategy. You seem to have omitted part of the questin. What tools are you talking about? Monetary policy ...

**Science Question 1**

terrestrial

**Biology**

Hi, I have 4 questions regarding Biology. 1. Does a different chromosome number in two species represent a significant difference? 2. Chromosome 7 has an extra band at the top in chimpanzees; does this extra band affect the quantity of coding DNA? And does it make a ...

**Chemistry (Check)**

there are seven base units not five

**Algebra**

How do you solve for x in this problems?? bx-2=10 x/2+e=9 5x+e=9 These are rather trivial. I will do one. The second: subtract e from both sides, then multiply both sides by 2.

**decision making**

Your manager is concerned and wants to make sure that you learned from this mistake and the likelihood of this happening in the future is minimal. Therefore she would like you to email her a reflective analysis about that decision. Be sure to address the following in your ...

**math**

Write in decimal form.94 17/ 1,000

**CHEM**

in addition to previous Q: for eg: why is the oxidation state (#) of Ca in CaH2 "+2"? According to a p.table I have here +2 is the only oxidation # for Ca...but how is that figured? One other eg: the oxidation state (#) of the maganese atom in KMnO4.6H2O is "+7&...

**CHEM**

What is the exact method/formula used to calculate oxidation state #'s? & how does one know when to use the correct oxidation state #? For example: Carbon carries 4,2,-4; Cl= 1,5,7,-1; and, Mn=2,3,4,7. Thanx. You use the seven rules in your text. Assigning of the oxidation...

**CHEM**

A gaseous hydrocarbon (an organic compound consisting of C & H) weighing 0.232g occupies a volume of 102mL at 23 degrees Celcius and 749mmHg. Calculate the molar mass and identify the compound. The compound is: a)C2H4 b)C3H6 c)C4H8 d)C5H10 e)C6H12 How is this problem worked ...

**CHEM**

thank you VERY much for your replies, DrBob. Another question, however: How many moles of ions -both cations and anions- are present in solution when 0.75 mol of potassium chloride is dissolved in 0.25L of distilled water? How do I work this answer to be: 1.5mol? KCl(s) + H2O...

**CHEM**

how do I work this question out?: 50.00g of NaCl are dissolved in water to give a solution that contains 2.500% NaCl by mass. The density of the solution is 1.030g/mL. The volume of the solution is: a)941.8mL; b)1.942L; c)2.500L; and, d)50.0mL. I know the answer is "b&...

**Math**

Find X 27^4x-2=243^3x=6 Please Explain Thanks Is this a repeat of the problem you posted earlier? If so, it should be 274x-2 = 2433x+6 You might try it the hard way. (4x-2)*log 27 = (3x+6)*log (243) Solve for x. I get -12. Post your work if you get stuck. You have too many = ...

**Math**

Find X 27^4x-2=243^3x+6 Please explain how to do it. Thanks 27^(4x-2)=243^(3x+6) Notice that 27 and 243 are both multiples of 3 Changing them.. (3^4)^(4x-2)=(3^6)^(3x+6) 3^4(4x-2)= 3^6(3x+6) taking the log base 3 of each side. (4x-2)= (3x+6) and solve for x. That doesn't ...

**Chem**

what is NH3 in written form? ammonia As a note, it is becoming more and more common to see ammonia written in IUPAC form, H3N, and the ammonium Ion written as H4N+

**presentations**

Imagine you have a meeting with the CEO and other high ranking officers of a company that invests in distance learning start-ups. Your objective is to obtain a loan for a distance learning company that you would like to start. Fortunately, you have a mentor to whom you can ...

**Business Management**

As your first job as the new manager at the outdated, adversarial company, write a plan for changing its organizational structure, incorporating the following elements: Your vision of the new organizational structure for your division including how you would realign ...

**science**

chemical changes: hydrogen + oxygen = water or H20 and carbon+ oxygen = carbon dioxide or C02. Equation for the above are: Hydrocarbon + oxygen = carbon dioxide + water + energy. CH4+202 = C02+2H20 Physical changes are: wax (solid) melts into liquid. some of the waxy liquid ...

**Chem**

Are: Ba(NO3)2, Ti)2, MgI2, and Ca(CH3COO)2 soluble or insoluble in H2O @ 25degrees C? Here is a site that lists the solubility rules. You should know this table; eventually you will want to know it so well that it is memorized. If you still have questions after viewing this ...

**CJ -- proofread please**

The federal criminal pretrial process begins with the first appearance. This appearance is held before a magistrate during which the legality of the defendant’s arrest is initially assessed and the defendant is informed of the charges on which he or she is being held (...

**Statistics**

lol