Wednesday

April 16, 2014

April 16, 2014

Total # Posts: 2,796

**Chemistry**

1) What is the atomic # for selenium? 34 2) Write the full electron configuration for selenium following the (n+l) rule? I am not sure what is meant by n+l 3) write the electron configuration, grouping electrons by their "n" values. [Ar]3d10 4s2 4p4 Are these correct...

**Chemistry(Please check)**

Thank you!

**Chemistry(Please check)**

1)For an atom of carbon how many valence electrons are "s" electrons? 2 2) How many are "p" electrons? 4 3)How many (total) electrons in carbon are paired? 2 4) How many are unpaired? 1 Are these correct.

**chemistry**

Based on the nl designation and max # of electrons above, write the electron configuration for carbon. 1s2 2s2 2p2 or [He]2s2 2p2 How many electrons are in the first shell n=1? These are the core electrons for carbon. I think two are in the first shell How many valence electro...

**chemistry**

the question then says to expand the above values in the table for all the l values of n=4. Are more possible for n=5? I am not sure what they mean by expand it but I think that there are more values for n=5.

**chemistry**

ok so for n=3 and l value 0 it would be the the nl would be 3s and max electrons would be 18?

**chemistry**

o ok. In my textbook it shows a chart with electron shells and it has the maximum electrons possible for nth shell (2n^2). What does this mean?

**chemistry**

So for the following: 1)n=2 2) l=0 3) l letter= s 4) nl designation= 2s Are numbers 2 and 3 correct?

**chemistry**

o ok i think i understand and what would the maximum number of electrons be?

**chemistry**

write the corresponding subshell leters for the combinations given. Fill in the possible number of electrons for these subshells. 1) n=1 2) l value=0 3) l letter? 4) "nl"Designation 5) Maxium # of electrons the table shows n values of 1, 2,2,3,3,4 with l values of 0,...

**Chemistry**

In the cchemistry lab we conducted an experiment called atomic spectroscopy. We had to find the color, energy, wavelength, and 1/lamda for Hydrogen, neon, and mercury. For hydrogen: red 1.90ev 650nm 1.54e^-3 red 2.02ev 610nm 1.64e^-3 green 2.30ev 545nm 1.83e^-3 for neon: green...

**Chemistry**

In the cchemistry lab we conducted an experiment called atomic spectroscopy. We had to find the color, energy, wavelength, and 1/lamda for Hydrogen, neon, and mercury. For hydrogen: red 1.90ev 650nm 1.54e^-3 red 2.02ev 610nm 1.64e^-3 green 2.30ev 545nm 1.83e^-3 for neon: gree...

**Chemistry**

on the x axis was 1/wavelength (nm-1) and the y axis was energy(ev). The line for both graphs of neon and hydrogen was positive. So would I pick two points on the graph to find the slope and then do h=slope/c?

**Chemistry**

In the cchemistry lab we conducted an experiment called atomic spectroscopy. We had to find the color, energy, wavelength, and 1/lamda for Hydrogen, neon, and mercury. For hydrogen: red 1.90ev 650nm 1.54e^-3 red 2.02ev 610nm 1.64e^-3 green 2.30ev 545nm 1.83e^-3 for neon: green...

**Chemistry**

Consider the last electron in B: Values for n,l,and ml of 2,0,0 cannot be used. Why not? so is this the same answer as lithium. The ground stat cant have l=2 since it has no p electrons? Are values of 3,0, 0 allowed? Why or why not? I would say no for the same reason. Are thes...

**Chemistry**

What are the n,l,ml,and ms values for the last electron in Be?

**chemistry**

Consider the last electron in Li: Values n,l,ml,and ms of 1,1,0, +1/2 are not allowable. Why not. I do not understand this question. I am not sure what the values for the last electron would be.

**Chemistry**

Electron Configuration: What numerical values of l are possible for n=4. 1,3,5,7 what ae their corresponding letters. s,p,d,f Are these correct?

**Chemistry**

o ok thank you!!

**Chemistry**

Thank you and sorry. Sometimes it does not show up on my computer when someone answers.

**Chemistry**

Write the n, l, ml, and ms values for the first two elements, H and He. H: n=1 l=0 ml=0 ms=+1/2 He: n=1 l=0 ml=0 ms=+1/2 for the first electron for the second: n=1 l=0 ml=0 ms=-1/2 Are these correct?

**Chemistry(Please check)**

Write the n, l, ml, and ms values for the first two elements, H and He. H: n=1 l=0 ml=0 ms=+1/2 He: n=1 l=0 ml=0 ms=+1/2 for the first electron for the second: n=1 l=0 ml=0 ms=-1/2 Are these correct?

**Chemistry**

ok thank you!!

**Chemistry**

For each l value indicate the ml values allowable? l=1 ml=+1, 0, -1 l=2 ml=+2,+1,0,-1,-2 l=3 ml= everything from +3 to -3 l-4 ml= everything from +4 to -4 Are these correct? What are the ms values allowable? These I am not sure about. Is it the number of orbitals?

**Chemistry**

Quantum numbers: What are the n values that are allowed? I put 1,2,3,4, etc. For the first four of these, indicate the l values allowed. n=1 l = 0 n=2 l = 0,1 n=3 l = 0,1,2 n=4 l = 0,1,2,3 Are these correct?

**derivatives**

How do you find the derivative of (6 csc x)/x?

**derivatives**

I know. I just realized that I messed up what goes where when I was doing it myself. My problem is applying it to other problems, esp when i also have to use the quotient or product rule.

**derivatives**

I know. I just realized that I messed up what goes where when I was doing it myself. My problem is applying it to other problems, esp when i also have to use the quotient or product rule.

**derivatives**

Thanks. My teacher told us we need to use the chain rule in these problems, and i'm having trouble figuring out when and where to use it.

**derivatives**

how do u find the derivative of (csc x)^7 -cos 4x???

**Calc**

to find an arcsin you would just have to memorize the unit circle right? so arccos of -sqrt3/2 is 5pi/6?

**Calc**

oops mixed up 2 questionss haha

**Calc**

How do you do the derivative of an inverse trig function? arcsin (sqrt2/2)??

**Chemistry**

yes thank you i understand the parts for moles of KHP and NaOH. So the mw of KHP was given to me which was 204.44g/mol so for moles of KHP i did 1/204.44 and got 0.004 and then for NaOH i got 0.004 as well. Then for the concentration of NaOH would i do 0.004/0.0145 and 0.004/0...

**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 bure...

**Chemistry(Please help, thank you!!)**

Thank you!!

**Chemistry(Please help, thank you!!)**

ok i do not understand at all but thank you for your help.

**Chemistry(Please help, thank you!!)**

SO would it be 27.80 / 10.00?

**Chemistry(Please help, thank you!!)**

Determine the concentration of a NaOH solution if 27.80mL of NaOH is required to neutralize 10.00mL of a 1.00 M H2SO4 solution. (Hint:Review monoprotic vs. diprotic acids.) would I do (27.80)(10)? Thank you for your help!!

**Chemistry(Please help, thank you!)**

ok so for mole of kHP it would be 1/204.44 = 0.00489 g/mol? The volume of NaOH for trial 1 was 14.50 mL and for trial 2 it was 9.90mL. So would it be 39.998 which is molecular mass of NaOH divided by the volume?

**Chemistry(Please help, thank you!)**

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 bure...

**Geology**

For my final I am to write a paper discussing the following : Select some product produced in your city or state that is made from earth, mineral, or energy resources. One example would be the tar paper used as a building material. (Do not use this example). Prepare a 700- to ...

**Chemistry**

Thank You!!!

**Chemistry**

A concept map was to be created on acids and bases. The concept terms that were given to use were: aqueous solution,bases,acids,ions,weak bases, strong bases, strong acids, weak acids,dissociation, weak electrolyte, strong electrolyte,reaction,salt, neutralization, hydronium i...

**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 bure...

**Science- physics**

Thank you so much! My teacher has NO idea how to teach us anything! I really appreciate your help! Thanks <3

**Science- physics**

How much does a 20ft x 10ft x 8ft swimming pool filled with water weight? Assume the water has a weight density of 62 lbs/ft3. I know the answer is 99,200 pounds but how do I get that answer? Thanks<3

**Science- physics**

An aluminum bar weighs 17 pounds in air. How much force is required to lift the bar while it is immersed in gasoline? The weight of aluminum is 170 pounds/ft3 and that of gasoline is 42 pounds/ft3. I know that the answer is 12.8 pounds but how do I get to that answer? Thanks<3

**Science- physics**

An iron anchor weighs 250 pounds in air and has a weight density of 480 lbs/ft3. If it is immersed in sea water that has a weight density of 64 lbs/ft3, how much force would be required to lift it while immersed? I know the answer is 217 pounds but I need help on trying to get...

**Science- physics**

A balloon weighing 80 kg has a capacity of 1200 m3. If it is filled with helium, how great a payload can it support? The density of helium is 0.18 kg/m3 and the density of air is 1.30 kg/m3. Express your answer in Newtons. I know the answer is 12, 400 Newtons I just don't ...

**Science**

The formula for density is... density= mass/volume So yes you would divide 6773 g/500 mL!

**Chemistry**

For my first trial KHP was 1.00g and for the second trial it was the same. So to find moles of KHP would I do 204.44g/mol X 1/1g which would be 204.44g/mol?

**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 bure...

**Chemistry**

Write a net ionic equation for the overall reaction that occurs when aqueous solutions of potassium hydroxide and carbonic acid are combined. KOH + H2CO3 = KCO3 + H30 K^+(aq) + OH^-(aq) + h2CO3 (aq) = K^+(aq) + CO3^2+(aq) + H3O(aq) Is this correct so far?

**science **

If a scientist changes two variable he/she would not know which change would increase or decrease his/her theory or hypothesis. The scientist wants to determine one thing that changed it the most not two things!

**Ap chem**

When .4000 g of CH4 is burned in excess oxygen in a bomb calorimeter that has a heat capacity of 324, the temperature increases 6.795 degrees celsius. How much energy is released? (in kJ/mol CH4)

**Science**

A container with equal sides of 8 cm is filled with 1200g of fluid. What is the force in Newtons on the bottom of the container?

**math**

a rectangle has an area of 330m^2 , one side is 7 m longer than the other what are the dimensions of this rectangle

**Math**

Simplify a)(1-ã3)(2+ã6)(5+ã2) b) -5ã45+ã52+3ã125

**5th grade math**

seventy five multiplied by one hundred twenty

**science**

how long does a teenager need to sleep at night?? my teacher asked this question and if you get it right, you get 2 extra points on a test, so please help me!!

**Physical Education**

P.E. is a time to achieve physical activity. To obtain a healthy living style you should exercise for 60 min a day. Most kids/teenagers would probably not chose to do that therefore schools decided to include that needed exercise in the kids' school time.

**Spanish **

I'm in the 8th grade and I have been taking French now for about a 1 1/2. I have learned many things and it is probably the easiest way to learn about another country! salut! (thats goodbye in french btw)

**Chemistry**

The empirical formula for Brilliant Blie dye is C37 H34 N2 O9 S3 Na2, and the formula weight is 792.86 g/mol. How would you prepare a 4.73 X 10^-6 M solution of Brilliant Blue dye? How many grams of the dye do you need to add to a 1.00 L of water to make this solution? I have ...

**Chemistry**

To calculate the percent error you would use the error in measurement divided by accepted value times 100 correct? So for an experiment in which you had to find the concentration of a dye in a powdered drink solution, to find the percent error would you use the number you calu...

**Chemistry**

A sample of 30.0 mL of sulfuric acid solution was titrated with 0.720 M KOH. It was found that 46.9 mL of the base was needed to neutralize the acid. What is [H2SO4]? would you do (30.0)(0.720) / 46.9 ?

**Chemistry**

What volume of o.410 M HNO3 would you need to neutralize 18.75mL of 0.376M Ba(OH)2? Would you do (0.410)(18.75) / 0.376? Or (0.410)(0.376) / 18.75

**Chemistry**

Oh ok thank you!

**Chemistry**

If 7 mL of water is added to 3 mL of a 0.50 M KOH solution, the concentration of KOH is changed to? I am not sure how to go about doing this. Please help, thank you!!! Would I do (7)(3) / 0.50?

**Chemistry**

so would it be Mg3N2 + H2O -> 2MgOH + NH3

**Chemistry**

Write the balanced equation for: Magnesium nitride + water -> magnesium hydroxide + ammonia MgNO2 + H2O -> MgOH + NH3 Is this correct?

**Chemistry**

thank you!

**Chemistry**

Would this be correct for the complete equation? Ba^2+ + OH^- + H^+ + Br^- = Ba^2+ + Br^- + H2O

**Chemistry**

Write the net ionic equation for the reaction that occurs when aqueous solutions of barium hydroxide and hydrobromic acid are combined. I know that the first part of the formula would be BaOH + HBr but I do not know what the product would be since HBr is one thing. I do not kn...

**Language**

What do these sets of words have in common?(Hint: Look for a sound, a keyboard, or the way they are written.) BCDEGPV QWERTYUIOP ij

**Language**

What do these sets of words have in common?(Hint: Look for a sound, a keyboard, or the way they are written.) BCDEGPV QWERTYUIOP ij

**english**

Where is pride and prejudice does mr. bennet confess that he married mrs. bennet because of her looks? a volume and chapter would be great:) I know the page numbers will be different in eat edition.

**algebra**

If you enter Interstate 40 at mile marker 23 in Sayre, Oklahoma, how far would you need to travel to reach mile marker 125 in El Reno, Oklahoma? After reaching El Reno, you might worry that your vehicle is running low on fuel. You know that your vehicle can travel 32 miles per...

**Chemistry**

is L the volume?

**Chemistry**

when doing a lab experiment on limiting reagents for CoCl2 there is a chart to fill out that says to find the concentration of test tubes 1-6, find the volume delivered and find the moles of CoCl2. How would I find the moles of CoCl2 for each test tube?

**Chemistry(please check, thank you!!)**

Thank you!

**Chemistry(please check, thank you!!)**

Is this equation balanced? CoCl2(aq) + Na2CO3(aq) -> CoCO3(s) + 2NaCl(aq) I think that it is because there is 1 Co on the left and 1 on the right. There is 2 cl on the left and 2 on the right. 2 Na on the left and 2 on the right and 3 CO on left and on right. Am I correct?...

**history**

When were hunter gatherers around in america? why and when(a date or range would be great) did they settle down?

**Chemistry, Need Help!!**

a)How many grams of H2 are needed to produce 14.27 g of NH3? b)How many molecules (not moles) of NH3 are produced from 1.57×10−4 g of H2 ?

**Chemistry**

A)What mass of carbon dioxide is produced from the complete combustion of 7.00×10−3 g of methane? B)What mass of oxygen is needed for the complete combustion of 7.00×10−3 g of methane?

**calculus**

Let f(x)=6x+16x^2 . Then the equation of the tangent line to the graph of f(x) at the point (2,16) is given by y=mx+b for m= and b=

**Chemistry**

If the standard state of sufur is S8 (s), which of the following equations represents the standard enthalpy of formation of H2SO4 (ℓ) ? A. 2H (g) + S (g) + 4 O (g) H2SO4 (ℓ) B. H2 (g) + S8 (g) + 2 O2 (g) H2SO4(ℓ) C. H2SO4 (ℓ) ...

**Chemistry**

Calculate the enthalpy change, ΔrH, for the following reaction, 4 NH3 (g) + 5 O2(g) → 4 NO (g) + 6 H2O (g) given the thermochemical equations below. N2 (g) + O2 (g) → 2 NO (g) ΔrH° = +181 kJ N2 (g) + 3 H2 (g) → 2 NH3 (g) ΔrH° = ...

**Chemistry**

If H for the reaction I2 (s) 2I (g) is 153 kJ/mol. What is the longest wavelength of light that can break an I – I bond? In other words, what is the minimum energy, expressed in terms of wavelength, required to break one I – I bond? A. 246 nm B. 465...

**Chemistry(Please check)**

What is the oxidation number of chromium in K2Cr2O7 so k=+1 (2) = 2 O=-2(7) = -14 2x + 1 +(-14) = 0 2x-12=0 x=6 so Cr is 6 Is this correct?? Thank you!!

**math**

are we allowed to use calculators in sat 1 math?

**math**

A rectangle was constructed using 24 square tiles. If you add the length and width of her rectangle together, you would get 11. What is the length and width of this rectangle?

**Chemistry**

What is the oxidation number of chromium in K2Cr2O7? I know that K = 1 O=-2 so 7*-2=-14 I do not know what to do now. Thank you for your help!

**7th grade math**

it is a grid 0,5.10.15,20 thru 55 then it cost a camp;er 25.00 how does this work??

**7th grade math**

i need help with variables and patterns algebra

**Chemistry(Please help, thank you!!)**

Thank you. I understand how you got the numbers for Na and H and the -6 for O but why does S have to be +4?

**Chemistry(Please help, thank you!!)**

What is the oxidation number of sulfur (s) in NaHSO3? I know that Na is 1 but I do not know what else to do. Please explain, thank you for your help!!

**Chemistry**

When aqueous CuSO4 is added to aqueous Na2S2O3, why is there no reaction?

**Physics**

Can you explain how to figure this out? A helicoptor accelerates at a rate of 2m/s^2. If you drop a rock out of the helicoptor 3 seconds after takeoff how high is the helicoptor when the rock hits the ground. Thanks

**physics**

Two particles are at the same point at the same time, moving in the same direction. Par- ticle A has an initial velocity of 9 m/s and an acceleration of 2.7 m/s2. Particle B has an initial velocity of 2.9 m/s and an acceleration of 4.2 m/s2. At what time will B pass A? Answer ...

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