Sunday

February 14, 2016
Total # Posts: 132

**MATH-Please Help me**

a menu which serves 4 people requires 3 cups of flour.how many cups of flour are needed for the menu to serve 12 people?
*September 7, 2015*

**Math**

a menu which serves 4 people requires 3 cups of flour.how many cups of flour are needed for the menu to serve 12 people?
*September 7, 2015*

**finance**

Chip’s Home Brew Whiskey management forecasts that if the firm sells each bottle of Snake-Bite for $20, then the demand for the product will be 15,000 bottles per year, whereas sales will be 91 percent as high if the price is raised 11 percent. Chip’s variable cost ...
*September 28, 2013*

**finance**

5.Capital Co. has a capital structure, based on current market values, that consists of 21 percent debt, 9 percent preferred stock, and 70 percent common stock. If the returns required by investors are 10 percent, 12 percent, and 17 percent for the debt, preferred stock, and ...
*September 28, 2013*

**math**

use substitution to solve this linear system: 8x + y = -458 -5x + 3y = 221
*June 11, 2013*

**math**

no idea . please help!
*June 11, 2013*

**math**

Model this situation w/ a linear system: Melissa borrowed $10, 000 for her university tuition. She borrowed part of the money at an annual interest rate of 2.4 % and the rest of the money at an annual rate of 4.5 %. Her total annual interest payment is $ 250.50 a.) a + b = 10 ...
*June 11, 2013*

**math**

Sales clerk at an appliance store have a chance of 2 payment: Plan A: $580 every 2 weeks plus 4.2 % commission on all sales Plan B: $880 every 2 weeks plus 1.2 % commission on all sales a) Write a linear system to model this situation b) Graph the linear system in part a c) ...
*June 11, 2013*

**math**

will it work if i write : they have the same slope and are identical. Both have the slope of 2/5?
*June 11, 2013*

**math **

Explain what happens when you try to solve this linear equation using an elimination strategy. What does this tell you about the graphs of these equations? -8x + 20y = -40 24x - 60y = 120
*June 11, 2013*

**math **

Model this situation w/ a linear system: Melissa borrowed $10, 000 for her university tuition. She borrowed part of the money at an annual interest rate of 2.4 % and the rest of the money at an annual rate of 4.5 %. Her total annual interest payment is $ 250.50
*June 11, 2013*

**math**

please get back asap
*June 11, 2013*

**math**

is the answer 3x -2y -17= 0?
*June 11, 2013*

**math **

write an equation in general form for the line that passes through A(3,-4) and B(11, 8)
*June 11, 2013*

**math **

Create a linear system to model this situation. Then use substitution to solve the linear system to solve the problem. - Bobbie has been saving dimes & quarters to buy a new toy. She has a total of 28 dimes and quarters, with a value of $4.30. How many of each type of coin ...
*June 11, 2013*

**math **

cashew nuts sell for $21.00/kg. Brazil nuts sell for $15.00/k. A distributor sold a total of 120 kg of nuts and Brazil nuts for $2244. What mass of each type of nut was sold?
*June 11, 2013*

**algebra 2 **

How do you find the points of intersection, if any, of the equations: x^2 + y^2 = 5 x - y = 1
*September 6, 2011*

**us history **

how was president Woodrow Wilson truly a progressive president?
*September 23, 2010*

**world history**

i don't get the question because at the time in which they developed, the US didn't even exist.
*May 3, 2010*

**world history**

the question is: Why is England and France developing into nations important to us? i need websites where i can get information on this please
*May 3, 2010*

**Chemistry**

I figured out the first one...still struggling with the 2nd...
*April 16, 2010*

**Chemistry**

Q1. The blood volume in a cancer patient was measured by injecting 5.0 mL of Na2SO4(aq) labeled with 35S (t1/2 = 87.4 d). The activity of the sample was 300 µCi. After 22 min, 12.9 mL of blood was withdrawn from the man and the activity of that sample was found to be 0....
*April 16, 2010*

**Chemistry**

I also posted the above well before Dr. Bob had answered one of my other questions...
*April 16, 2010*

**Chemistry**

I wasn't talking about DrBob being rude...that would be bobpursely...DrBob has been nothing but helpful while I have used this site as a resource.
*April 16, 2010*

**Chemistry**

One last question...even though no one seems to be willing to help me out without being rude. The blood volume in a cancer patient was measured by injecting 5.0 mL of Na2SO4(aq) labeled with 35S (t1/2 = 87.4 d). The activity of the sample was 300 µCi. After 22 min, 12.9 ...
*April 16, 2010*

**chemistry**

Could you please just explain what I am doing wrong so that I can know how to approach these problems? I appreciate the advice and am well aware I need to go to bed...but I have to get these finished and my professor is out of town attending a memorial service and unable to ...
*April 16, 2010*

**chemistry**

Sleep is a bit of a luxury.....unfortunately I'm one of those students that doesn't have an option of taking a lighter load or working less....luckily I graduate in a few weeks. In the meantime I need to finish these problems so that I can go to bed....but they are due...
*April 16, 2010*

**chemistry**

Another attempt I made gave me relatively "reasonable" answers...but still doing something wrong. I converted the minutes to days and used that in the rate to find k via k= rate/N ; N being 3.25E18 atoms. this calculated k to be .00145. I plugged this into N'=Ne...
*April 16, 2010*

**chemistry**

Oh and when I try to put this into my calculator I get 0... sorry if I am not catching on fast enough for some....I worked graveyard last night and Haven't slept in over 35 hours...
*April 16, 2010*

**chemistry**

A radioactive sample contains 3.25 1018 atoms of a nuclide that decays at a rate of 3.4 1013 disintegrations per 26 min. (a) What percentage of the nuclide will have decayed after 159 d? % (b) How many atoms of the nuclide will remain in the sample? atoms (c) What is the half-...
*April 16, 2010*

**Chemistry**

A sample of pure cobalt-60 has an activity of 8 µCi. (t1/2 cobalt-60 = 5.26 a) (a) How many atoms of cobalt-60 are present in the sample? atoms (b) What is the mass in grams of the sample? g The way I approached part a was to first convert the microCi into Bq (for a ...
*April 16, 2010*

**Chemistry**

A certain Geiger counter is known to respond to only 1 of every 1000 radiation events from a sample. Calculate the activity of each radioactive source in curies, given the following data. 580 clicks in 104 s My text barely attempts to explain how to do this problem, and there ...
*April 16, 2010*

**Chemistry**

A certain Geiger counter is known to respond to only 1 of every 1000 radiation events from a sample. Calculate the activity of each radioactive source in curies, given the following data. My text barely attempts to explain how to do this problem, and there is no example. I am ...
*April 15, 2010*

**Chemistry**

no problem :)
*April 13, 2010*

**Chemistry**

Think of the equations you have learned and which variables you have been given. It helps to keep a list of them in front of you so you can quickly figure it out. Then just plug in. If you have P, V, mass, and T....you're going to use PV=nRT...just solve for P PV=nRT is an...
*April 13, 2010*

**Chemistry**

Nevermind...I realized that the problem I was using as an example called for 1 g of the reactant used....this didn't....so I have my correct answer now. Thanks! Still stumped on my earlier question though...
*April 13, 2010*

**Chemistry**

How much energy is emitted in each α decay of plutonium-234? (234Pu, 234.0433mu; 230U, 230.0339mu; 4He = 4.0026 mu). I tried finding the difference in mass first: (230.0339 + 4.0026) - (234.0433) = -.0068 mu I then converted from amu to kg by multiplying by 1.6605E-27. ...
*April 13, 2010*

**Chemistry**

Hmm...I don't know. My webassign is telling me it's not a neutron. Thanks
*April 13, 2010*

**Chemistry**

Oh i just realized how you typed the equation has the product flipped. so it's 1,1,H + 1,1P --> 2,1H + ? order is A,Z,X where A is mass and X is the particle or element
*April 13, 2010*

**Chemistry**

neutron was my first answer...i am using +1 e^0 to be a positron though, not electron.
*April 13, 2010*

**Chemistry**

I know they need to balance out on both sides. I am just confused because I am pretty sure it should be 0,+1, e ...e being X. Webassign is telling me this is wrong but if that's true I don't understand why and need that explained....
*April 13, 2010*

**Chemistry**

for A, Z, and X I'm typing it in the form A,Z,X (or X as a particle) since I obviously can't do sub or superscript... 1,1,H + 1,1,p --> 2.1,H + ? I thought initially the missing particle at the end would be either 0,-1,e or 0,1,e (beta emission/decay) but apparently...
*April 13, 2010*

**Chemistry**

How can you tell if [ MnCl6]4- or [ Mn(CN)6 ] 4- has the longer wavelength of light? and then how do you figure out how many unpaired electrons each has?
*April 8, 2010*

**Chemistry**

Is Zn+2 diamagnetic or paramagnetic? I am a little confused on how to figure this out and I'm finding inconsistent answers when I tried to look this up. Thanks!
*April 8, 2010*

**Chemistry**

How can you tell if [ MnCl6]4- or [ Mn(CN)6 ] 4- has the longer wavelength of light? and then how do you figure out how many unpaired electrons each has?
*April 8, 2010*

**Chemistry**

Trying to name this compound and figure out its oxidation state [ CoBr2(NH3)3(H2O) ]+ I came up with triammineaquadibromocobalt(II) ion with a +3 oxidation state...but not sure if this is right... similarily for [Fe(ox)(Cl)4]3- I came up with tetrachlorooxalatoferrate(IV) ion ...
*April 7, 2010*

**Chemistry**

Which one of the following combinations of reagents will result in a spontaneous reaction? A) Al(s) + CuCl2(aq) B) Al(s) + CaCl2(aq) C) Zn(s) + CaCl2(aq) D) Cu(s) + ZnCl2(aq) I know the answer is A, but what I don't know is why, or how to figure this out. Thanks!
*April 6, 2010*

**Chemistry**

You know it's second order so your rate=k[NO2]^2 All you do is like you said, find moles, use that to find molarity (convert mL to L) and then plug the concentration into the equation. You're given the k. Same thing with part B, just changing the concentration :)
*March 31, 2010*

**Chemistry**

All you have to do is find the concentration of OH- and solve for pH (pOH= -log [OH-] nad then 14-pOH=ph [OH-} = Ksp/[M+}
*March 19, 2010*

**Chemistry**

NVM i was using the pKA instead of pH....i had it right afterall...guess it's jsut time for bed....
*March 16, 2010*

**Chemistry**

I figured out the correct new pH for each respective part, but apparently the initial pH i found for the buffer solution is incorrect. I just need help in figuring that so I can calculate the change. I initially thought the buffer pH was 7.38. Thanks!
*March 16, 2010*

**Chemistry**

for part a I tried using the HH equation, found moles of NaOH and used that for [base] and moles Na2HPO4 as [acid]...i used pKa 7.21...that was incorrect. For part b I used a similar method...plugging in HNO3 as the [acid] and Na2HPO4 moles as [base] the other pka values for ...
*March 16, 2010*

**Chemistry**

A buffer solution of volume 100.0 mL is 0.150 M Na2HPO4(aq) and 0.100 M KH2PO4(aq). Refer to table 1. (a) What are the pH and the pH change resulting from the addition of 80.0 mL of 0.0500 M NaOH(aq) to the buffer solution? pH pH change (include negative sign if appropriate) (...
*March 16, 2010*

**Chemistry**

I'm confused how I would use the Ka equation in the HH equation??? I thought HH was just pH=pka + log([base]/[acid]) ...
*March 16, 2010*

**Chemistry**

Calculate the pH of the solution that results from mixing the following reagents. Refer to table 1. mix 0.189 L of 0.019 M (CH3)2NH(aq) with 0.327 L of 0.011 M (CH3)2NH2Cl(aq) I tried using the Henderson-Hasselbach equation by finding the pKa but it didn't work....I am ...
*March 16, 2010*

**Chemistry**

Nevermind I got it...I just mixed up my variables a little. thanks!
*March 16, 2010*

**Chemistry**

I am pretty stuck...not sure if I used the Henderson-Hasselbach the right way and I'm a little confused on how to set up the Ka expression...
*March 16, 2010*

**Chemistry**

I am trying to use pH=pKa + log(acid/base) to see where that gets me...I'm attempting to find the [base] using the given pH and pKa of 8.69 (for HBrO)...then use the concentration to find the new pH...
*March 16, 2010*

**Chemistry**

The pH of 0.50 M HBrO(aq) is 4.50. Calculate the change in pH when 6.50 g of sodium hypobromite is added to 110. mL of the solution. Ignore any change in volume. Ka of HBrO is 2E-9 I found the amount of moles used for each (.0547 mol NaBrO, and .055 mol HBrO soln) I'm not ...
*March 16, 2010*

**Chemistry**

1x10-2 mol of MgSO4 (Ksp = 9) is added to 1 L of water. Will 1x10-5 mol of CaSO4 (Ksp = 10-6) completely dissolve in the solution? I think the answer is yes...because the Q will be less than Ksp of 10^-6?? Which of the following salts would you expect to result in the greatest...
*March 16, 2010*

**Chemistry (or Physio/Biochem)**

Asthma affects about seven percent of the population. During an asthma attack smooth muscle cells in the bronchi constrict, the airways become inflamed and swollen, and breathing becomes difficult. What effect might an asthma attack have on blood pH? A. pH goes down B. pH goes...
*March 14, 2010*

**Chemistry**

100 mL of each of the following solutions is mixed; which one of the mixed solutions is a buffer? A) 1.0 M NH3(aq) + 0.6 M KOH(aq) B) 1.0 M NH4Cl(aq) + 1.0 M KOH(aq) C) 1.0 M NH3(aq) + 0.4 M HCl(aq) D) 1.0 M NH4Cl(aq) + 0.4 M HCl(aq) E) 1.0 M NH3(aq) + 1.0 M HCl(aq) I am ...
*March 14, 2010*

**Chemistry**

Which of the following systems could act as a buffer? A. HCl/Cl- B. NaOH/OH- C. HSO4-/SO4-2 D. H3O+/OH- E. All of the above my guess is C because A and B are too strong, but I am unsure of D. Can someone explain how to think thru this?
*March 14, 2010*

**Chemistry**

Given the equilibrium rxn CF4(g) + 2H2O(l) ⇔ CO2(g) + 4HF(g) ΔH < 0 if pressure is increased by adding argon gas to the equilibrium, I know it doesn't decrease the amount of HF. But if a random gas is added for any equilibrium rxn, will it always cause an ...
*March 9, 2010*

**Chemistry**

If a weak acid is say only 5% ionized at equilibrium, then the ionization rxn would be reactant favored, correct? I am a little on the fence about understanding this if anyone could better explain why this would be? I am assuming because it is not completely ionized, the ...
*March 9, 2010*

**Chemistry**

I see how there are the numbers of particles in solution, I am a little confused on how that relates to these properties. My text is pretty brief over this section.
*March 7, 2010*

**Chemistry**

I am confused about why this is the answer to a practice problem I was given. (answer is c). Could someone explain why/why not for each answer? 2) Solution A is made from 1 L of water and 0.1 moles of Na(CH3COO), and Solution B is made from 1 L of water and 0.1 moles of Na2(...
*March 7, 2010*

**world history ancient greece**

i need to do an outline of how to organize things for my research report on the Ancient Olympics. How cna i divide up my report?
*March 2, 2010*

**Chemistry**

Right...I am confused on the solving for x part. Before when I have used this I have always been given ka or kb in order to solve for x. This time I'm not--so I don't know how to set up my equation to find x. Once I have x I know how to do everything else
*February 23, 2010*

**Chemistry**

Calculate the initial molarity of KNH2 and the molarities of K+, NH3, OH-, and H3O+ in an aqueous solution that contains 0.75 g of KNH2 in 0.255 L of solution. You may ignore the reaction of NH3 with water. I already found the initial molarity, but I am not sure how to find ...
*February 23, 2010*

**Chemistry**

Calculate the initial molarity of KNH2 and the molarities of K+, NH3, OH-, and H3O+ in an aqueous solution that contains 0.75 g of KNH2 in 0.255 L of solution. You may ignore the reaction of NH3 with water. I already found the initial molarity, but I am not sure how to find ...
*February 22, 2010*

**Chemistry**

Well I'm not actually making it in a lab...I just don't fully understand the concept of this
*February 21, 2010*

**Chemistry**

In a .1M aq. soln of NaCN, how would you determine the major species (other than water)? And how would you determine the pH (not exact pH, I just want to know how to know if it is acidic ie. <7, etc). Thanks in advance
*February 21, 2010*

**Physical Chemistry**

I figured out what I was doing...I ended up using the Van't Hoff Equation and the enthalpies of formation to solve for K at 100 C. This stuff is so time consuming...
*February 19, 2010*

**Physical Chemistry**

Calculate the equilibrium constant at 25°C and at 100.°C for each of the following reactions, using data available in Appendix 2A. Remember that the organic molecules are in a separate section behind the organic molecules in Appendix 2A. (a) HgO(s) Hg(l) + O2(g) at 25&...
*February 19, 2010*

**Chemistry Question!!**

When 1.00 g of gaseous I2 is heated to 1000. K in a 1.00 L sealed container, the resulting equilibrium mixture contains 0.830 g of I2. Calculate Kc for the dissociation equilibrium below. I2 <--> 2 I What I did was converted the initial I2 into moles then molarity since...
*February 19, 2010*

**Physical Chemistry**

When 1.00 g of gaseous I2 is heated to 1000. K in a 1.00 L sealed container, the resulting equilibrium mixture contains 0.830 g of I2. Calculate Kc for the dissociation equilibrium below. I2 <--> 2 I What I did was converted the initial I2 into moles then molarity since ...
*February 19, 2010*

**Science**

I've heard this one before: "A meteor is a flash of light made by a falling meteorite"
*February 15, 2010*

**Chemistry **

nevermind--after 50 hours of pulling my hair out I finally arrived at the answer :)
*February 15, 2010*

**Chemistry **

And when solving for molality do I need to use the formula dT=Kf*molality? Or do I find it independently of this equation?
*February 15, 2010*

**Chemistry **

I am confused by the 1% by mass part...I don't understand what it really even means or if I am multiplying something by 1% or what? I did eventually realize I had to multiply by 3--I have never seen a problem like that before so I was slow to catch on. Thanks for your help
*February 15, 2010*

**Chemistry **

A 1.00% by mass MgSO4(aq) solution has a freezing point of -0.192°C. Water has a kf of 1.86 (K·kg)/mol. (a) Estimate the van't Hoff i factor from the data. (b) Determine the total molality of all solute species. I can probably figure out the second part of the ...
*February 15, 2010*

**Chemistry**

I still need help with this problem... Calculate the concentration of the solution the molality of hydroxide ions in a solution prepared from 9.16 g of barium hydroxide dissolved in 179 g of water I do not know how to approach this...I keep doing something wrong.
*February 15, 2010*

**Physical Chemistry**

the answer for a was actually incorrect
*February 15, 2010*

**Physical Chemistry**

Got it. for A i was using molar mass for FeCl3 instead of water..oops. I solved C...but I am still confused with the second question of anyone can help me out... Thanks!
*February 15, 2010*

**Physical Chemistry**

Calculate the concentrations of each of the following solutions. (a) the molality of chloride ions in an aqueous solution of iron(III) chloride for which xFeCl3 is 0.0195 (b) the molality of hydroxide ions in a solution prepared from 9.16 g of barium hydroxide dissolved in 179...
*February 15, 2010*

**Physical Chemistry**

Just want to double check...so for KCl, because it is endothermic, my q should then be negative?
*February 10, 2010*

**Physical Chemistry**

Ok, thanks for your help
*February 10, 2010*

**Physical Chemistry**

no I didn't get that, but I was adding both 18g of the salt and 190 g of water for the m used in the equation. I'm still a little confused with the signs...I thought if it is releasing heat then q would be negative? I did manage to get the same value for q I just had ...
*February 10, 2010*

**Physical Chemistry**

Determine the temperature change when 18.0 g of the following salt is dissolved in 190. g of water. The specific heat capacity of water is 4.184 J·K-1g-1. The enthalpies of solution in the table are applicable. Do not take the added mass of the salt into account when ...
*February 10, 2010*

**Math**

I mean x is greater than or equal to, not less than. sorry.
*February 4, 2010*

**Math**

Solve the inequality: 2x-1 / 3x-2 < 1 [the < is actually less than or equal to] I got one of the answers, x is less than or equal to 1, but there's another. How do you find that answer? Thanks
*February 4, 2010*

**american lit. [[10th grade]]**

i need to write an essay about how holden caulfield from the catcher in the rye is fascinated with childhood and innocence. what can i include as examples for that?
*December 1, 2009*

**english/ literature/ essay**

oh thank you very much! :)
*September 16, 2009*

**english/ literature/ essay**

any other reasons? i had that reason well something like it...
*September 16, 2009*

**english/ literature/ essay**

hi i need help with this.. what is the importance of recognizing cultural differences as a young person in today's global society?
*September 16, 2009*

**algebra review!**

it says write the equation of the vertical line that passes through the point (7,-3). what do i need to start it off? find the equation for the line with undefined slope and passing through the point (-1,-2). what do i need to start that off? what equation do i use to find the...
*September 3, 2009*

**algebra review**

find the y-intercept of a line that passes through (2,1) and has a slope of -5. i forgot what equation i have to use to find this out. can someone give me which equation i have to use? or all the equations that deal with slopes please
*September 3, 2009*

**science- bio**

how can traits on a particular chromosome be determined? how can these traits determine the characteristics of an organism? what could happen if a base is out of order?
*March 26, 2009*

**not sure wat subject**

i need two examples of situations where you would think help/charity should be given but it didnt happen as you thought
*February 25, 2009*