Sunday

January 22, 2017
Total # Posts: 340

**CHEM**

a 250.0ml buffer solution is 0.250M in ascetic acid and 0.250M in sodium acetate. B). What is pH after addition of 0.0050mol of HCl? C). What is pH after addition of 0.0050mol of NaOH?

*March 28, 2012*

**Chem**

Find pH. A) 0.10M Zn(OH)4^-2 F) Zn(OH)2 in 0.010M ZnCl2 Q) 0.010 M Zn(NH3)4^+2 hint: fined [NH3] then kb for OH^- Im having trouble with these can someone help me.

*March 25, 2012*

**Chemistry!!!**

Consider a solution that is 0.022 M in Fe2+ and 0.014 M in Mg+2. A). If potassium carbonate is used to selectively precipitate one of the cations while leaving the other on solution, which cation will precipitate first? What minimum concentration of K2CO3 will trigger the ...

*March 21, 2012*

**Chem!!!:/**

Determine whether of not each compound will be more soluble in acidic soln than in pure water. Explain. A). Hg2Br2 B). Mg(OH)2 C). CaCO3 D). AgI I think acid, neutral,acid,neutral ??? Help please!:) thAnks

*March 19, 2012*

**precalc!!!!!**

I have to prove this: (a^3-b^3)= (a-b)(a^2+ab+b^2) How do I use long division to get (a^2+ab+b^2). I'm given..... 1). (a^3-b^3)/ (a-b) I cant get that answer. Help?

*March 19, 2012*

**precalc!!!!!**

Use long division : (a^3-b^3)/ (a-b)

*March 18, 2012*

**Chemistry**

Set Kc = (x)(0.2-x)/(0.2-x) . Solve for x. 0.2-x is H2S equilibrium concentration

*March 18, 2012*

**help chem!:/**

a) Calc. PH of 0.010 M HF and 0.030 M KF e) calc. PH Zn(OH)2 in wAter

*March 15, 2012*

**Chemistry**

1.CALCULATE pH of 1.0 L 0.010 M ascetic acid and 0.50 L 0.010 M NaOH. 2. Calculate pH of 1.0 L 0.010 M NaOH and 0.500 L 0.010M HCl Buffer help?

*March 15, 2012*

**ChemB**

CALCULATE PH OF THE SOLUTION THAT RESULTS FROM EACH SOLUTION A) 150.0mL OF 0.25M HF WITH 225.0 mL OF 0.30M NaF Help please, these buffer questions are confusing.

*March 12, 2012*

**ChemB**

A forming acid solution has a pH of 3.25. Which of these substances will raise the pH of the solution upon addition? Explain. A) HCl B) NaBr C) NaCHO2 D) KCl

*March 12, 2012*

**CHEMISTRY!!!=0**

OH, okay so when I produce a strong acid and a strong base it is neutral so pH=7. Meaning the 0.20M KI doesn't even matter?

*March 1, 2012*

**CHEMISTRY!!!=0**

Determine pH of each solution: 0.20 M KI i don't know how you know if you use.. K+H2O->KOH + H or... I- +H2O--> HIO +H Im thinking this one... I- + H2O --> HIO + H 0.20M--------------------0-----------0 0.20-x------------------x-------------x there is a Ka value ...

*March 1, 2012*

**CHEMISTRY!!!=0**

Determine pH of each solution: b) 0.20 M CH3NH3I I did.... CH3NH3^+ +H2O -> CH3NH2 + H3O^+ 0.20 ---------------0--------------0 0.20-x--------------x------------x so i got... ? =x^2/0.20-x i looked up in the back of the book and found the Kb of CH3NH2 to be 4.4 X 10^-4. do ...

*March 1, 2012*

**AP CHEMISTRY**

He got 62.5ml by making up a certain amount of volume for the 0.1M solution and setting it equal to the 0.08 NaOH( which is used to titrate the solution) and determined the amount of NaOH in milliliters needed until the solution hit its endpoint basically he used... M1 x V1 = ...

*March 1, 2012*

**CHEMISTRY!!!=0**

Determine the pH of each solution: (a) 0.10 M NH4Cl can someone show me how to do this one so i have the idea of how to do the rest. thanks!

*March 1, 2012*

**Chemistry**

Determine the Concentration of OH^-1 and pH of a solution that is 0.140 M F^-1. I did F- +H20 ---> HF + H20 but idk what to solve from there....

*February 28, 2012*

**Psychology**

my answers match up with your answers!!! :)

*February 20, 2012*

**Chidren,Families,and Society**

he has probably had a very violent family life, even though he is young, he might have picked up on family fights or feuds that have gotten ugly. he may be abused or he may have pre-k students bullying him. he could possibly have an anger management disorder.

*February 20, 2012*

**law**

Im not sure about elementary. child abuse maybe. In middle schools around here there are alot of drug sells and alcohol too. also a few bullying situations that lead to suicide, not sure how that helps. High school: drug abuse, alcohol abuse, underage drinking, domestic ...

*February 20, 2012*

**eng 22**

i would definitely go with paying attention to what the film has to say. Just my opinion though

*February 19, 2012*

**algebra**

no, she does not have enough. the shoes are $88 with the discount. so she needs $8. To figure this out, divide $132 by 3. multiply that by two and then you have the cost of the shoes.

*February 19, 2012*

**law**

i do not think that she should be able to obtain money from this. as the article says, she mislead investigators which is a serious federal offense. she is lucky that is the only consequences she got. she should be in jail or paying a fine.

*February 19, 2012*

**Last Chemistry Question!**

Yeah i got tht. I hope to make a difference in life some day like you are. Just not a teacher lol. i cnt handle bad kids. haha well ima let you get back to helping. Bye

*February 19, 2012*

**Last Chemistry Question!**

oh thts awesome! Thank you so much for all the help tonight. You Rock Dr Bob!!! :)

*February 19, 2012*

**Last Chemistry Question!**

lol anyone who can help me in any way, that person is my hero! So are you a real doctor? just curious lol!!! :)

*February 19, 2012*

**Last Chemistry Question!**

Awesome thanx man! u r my vertual hero!

*February 19, 2012*

**Last Chemistry Question!**

My teacher told me something about 22.4 liters. do you know what she was talking about?

*February 19, 2012*

**Last Chemistry Question!**

How do you Convert from Moles to Liters? Man i hate not understanding test prep material!

*February 19, 2012*

**Chemistry**

im almost positive that Kemo-Therapy for cancer treatment uses Radioactivity

*February 19, 2012*

**Chemistry**

X-rays

*February 19, 2012*

**Chemistry**

Thank you so much DrBob222

*February 19, 2012*

**Chemistry**

How many particles are in .169 moles of Potassium Sulfide?! What is the percent composition of sulfer in that same prolem?!

*February 19, 2012*

**Chemistry**

uhhh, chemical right?

*February 19, 2012*

**y no one anwering my ques**

oh my bad. sorry. biology was always tough for me

*February 19, 2012*

**y no one anwering my ques**

i believe the answer is #1

*February 19, 2012*

**writing**

hires sounds a little awkward. i think hirees should be placed in there instead of hires

*February 19, 2012*

**Geometry**

25.5 i think

*February 19, 2012*

**Chemistry**

thanx bunches!!! @(^_^)@

*February 19, 2012*

**Chemistry**

How many moles are in 12.0 grams of Potassium Sulfide?

*February 19, 2012*

**Science n math**

What is the molecular geometry n the electron domain for HCN

*February 15, 2012*

**Math**

An inner tube for a bicycle has a diameter of 2 inches and measures about 82 inches along its circumference. What formula would you use to determine the numbers of cubic inches of air the inner tube can hold

*February 2, 2012*

**Math**

An inner tube for a bicycle has a diameter of 2 inches and measures about 82 inches along its circumference. What formula would you use to determine the numbers of cubic inches of air the inner tube can hold

*February 2, 2012*

**Chemistry**

THE RATE LAW FOR THE REACTION 2NO + 02 = 2NO2 IS FIRST ORDER IN OXYGEN AND SECOND ORDER IN NO. PROPOSE A MECHANISM IN WHICH EACH STEP IS BIMOLECULAR. SPECIFY THE SLOW STEP. I HAVE NO IDEA WHAT TI DO. HELP PLEASE? THANKS.

*January 22, 2012*

**Math**

He would have gotten 10 free.

*January 11, 2012*

**Chemistry**

2 HCl react with 1 Zinc Single replacement rxn So 2.

*December 14, 2011*

**Calc**

I think.... A) -12 B) 1 C)-7

*December 14, 2011*

**Chemistry**

An 8.00 mass % aqueous solution of ammonia has a density of 0.9651g/ml. Calculate the molality, molarity, and mole fraction of NH3. This question seems simple but I cannot seem to remember how to do this. Help please?

*December 14, 2011*

**chem**

An industrial chemist is studying smAll organic compounds for their potential use as an auto antifreeze. When 0.243g of a compound is dissolved in 25.0 ml of water, the freezing point is -0.201 degree celcius. (A) Calculate the molar mass of compound (dH2O= 1.00g/ml) at temp ...

*December 14, 2011*

**trig**

Basically the arcsin is the same as sin^-1 so the sin^-1(.5)= 30 degrees You can use a unit circle or a 30-60-90 triangle to figure it out.

*December 13, 2011*

**trig**

How do i solve this equation over the interval [0degrees,360) cot(theta)+2csc(theta)=5

*December 10, 2011*

**math (taylor polynomials)**

Find the degree 3 Taylor polynomial T3(x) of the function f(x)=(7x+50)4/3 at a=2 Find the second-degree Taylor polynomial for f(x)=4x2−7x+6 about x=0 thank you! (:

*November 30, 2011*

**Math (linear approximation)**

Find a linear approximation of the function f(x)=(1+x)^(1/4) at a=1, and use it to approximate the numbers (.95)^(1/4) and (1.1)^(1/4). Round your answers to the nearest thousandth Cheers in advance!

*November 29, 2011*

**CHEM**

Compare the value you obtained from average bond energies: (260Kj) to the actual standard enthalpy of formation of gaseous benzene, 82.9 kj. What does the difference between these two values tell you about the stability of benzene?

*November 8, 2011*

**MATH**

You can plug in zero for x and solve for y. then plug in zero for y and solve for x to get your values for x and y. x=200 y=-100

*November 8, 2011*

**Further calculus**

1) A price p (in dollars) and demand x for a product are related by 2x^2+6xp+50p^2=10600. If the price is increasing at a rate of 4 dollars per month when the price is 30 dollars, find the rate of change of the demand. 2) a) The price (in dollars) p and the quantity demanded q...

*November 2, 2011*

**Calculus**

sorry accidentally reposted!!

*November 1, 2011*

**Calculus**

Answers to any of these questions would be of great help! (: 1 a) At noon, ship A is 150km west of ship B. Ship A is sailing south at 50km/h and ship B is sailing north at 30km/h. How fast is the distance between the ships changing at 4:00pm? b) A spotlight on the ground is ...

*November 1, 2011*

**Calculus**

thank you steve!

*November 1, 2011*

**Calculus**

Answers to any of these questions would be of great help! (: 1 a) At noon, ship A is 150km west of ship B. Ship A is sailing south at 50km/h and ship B is sailing north at 30km/h. How fast is the distance between the ships changing at 4:00pm? b) A spotlight on the ground is ...

*November 1, 2011*

**graphing**

Can someone explain what quadrant this would be in and the domain and range. I have no idea how to graph it. G(x)= -3sin^-1 (2x)

*October 29, 2011*

**Trigonometry**

Oh okay thanks!

*October 29, 2011*

**Trigonometry**

Write as an algebraic expression in u. Tan(cos^-1 u)

*October 29, 2011*

**MATH**

-8. Plug in -6 for x and solve.

*October 29, 2011*

**Quantatative Analysis**

Use M1V2=M2V2 Plug in your given molarity and volume and solve for V1.

*October 29, 2011*

**Trigonometry**

Oh okay thanks a lot:) I was distributing sec and couldn't' get anywhere. I didn't think of writing it like that.

*October 23, 2011*

**Trigonometry**

Prove identity. Sec(pi-x)=-sec x

*October 23, 2011*

**TRIG**

Verify the following identity. 1) sin(x+y) __________ = tanx+tany cosxcosy 2) Write cos3x in terms of cosx I cannot figure out how to solve for identities they are so hard. Any help appreciated!:)

*October 23, 2011*

**Chemistry 105**

Use Boyles Law. P1V1=P2V2 (33.0L)(1.1atm)=(P2)(10.0L) and solve for P2.

*October 23, 2011*

**TRIG**

1) Find an angle that makes the statement true: costheta =sin(3theta+10degrees) 2) Verify this proof: sec(Pie -x)= -secx Can someone show me how to solve for these. Very much appreciated!

*October 23, 2011*

**chemistry 105**

Use the ideal gas law.. PV=nRT and solve for moles of N2 SO.... (1.00atm)(.0599L)=n(0.0821L*atm/mol*K)(273K) solve for n. then use "n" moles of N2 and then set up an conversion factor. so.... ___moles of N2 x( 6mol Li/2mol N2) x (MolarMass Li/1mol of Li) Then that ...

*October 23, 2011*

**math2 calc**

Let f(x) be the function 11x2−9x+7. Then the quotient f(6+h)−f(6)h can be simplified to ah+b for: a= and b=

*September 28, 2011*

**Math- calculus**

Suppose f is a function which satisfies the properties: f(x+y)=f(x)+f(y)+x2y+xy2 for all real numbers x and y, and limx→0f(x)x=1. f′(x) thanks in advance!

*September 28, 2011*

**chem**

A student placed 12.0grams of glucose in a flask added enough water to dissolve glucose by swirling then added additional water until the .100 ml mark. A 60.0ml sample of this glucose soon was diluted to 0.500 L. How many grams of glucose are in 100. ml of the final solution.

*September 19, 2011*

**DRAMA**

Tragedy- the fall of a tragic hero Comedy- funny based on words

*September 18, 2011*

**trig**

Given the radius of a wheel is 12inches and the angular speed is measured to be 3pie/4 radiant per second, find the linear speed of the piece of gum stuck to the where. Give both an exact answer. And a decimal answer rounded to 4 decimal places.

*September 17, 2011*

**trig**

An automobile windshield washer 10inches long rotates an angle of 60degrres. If the rubber part of the blade only covers the last 9inches of the wiped, find the area of the windshield cleaned by the wiper.

*September 17, 2011*

**Chemistry - - Hydrocarbons**

oh then when you number your chain. CH is number 3. SO you would call the organic compound..... 3-MethylHexane

*September 17, 2011*

**Chemistry - - Hydrocarbons**

you count the longest chain so it will be the carbon chain of six. so hexane and then you have CH3 attached so it would be MethylHexane i believe.

*September 17, 2011*

**Chemistry 1**

the answer is 13180. you do what is in parenthesis first and round it 3sf and get 3770 and then add 9413.4... and then round to least number of decimal places so you would get 13180

*September 17, 2011*

**Trig**

how do i find the exact value of s [pie/2, pie] sin s = radical2/ whole number 2 what is s in radians? how do i figure this out without the use of a calculator. I drew the graph and located it in the second quadrant and i think the triangle is a 45-45-90 but i don't how to...

*September 15, 2011*

**chemistry**

combustion analysis of a hydrocarbon produced: 33.01 g CO2 and 13.51 g H2O Calculate the empirical formula of the Hydrocarbon. I got CH5 but that doesn't seem right? how do i do this problem?

*September 11, 2011*

**Chemistry**

well you have dipole-dipole London Dispersion and hydrogen bonds. you just classify which forces each are by reading your definitions of the three. LD are the weakest forces Hydrogen bonds are when two hydrogen bond with one another which is strong dp-dp forces are between one...

*September 9, 2011*

**Math**

...you multiply 4 by 3 to get 12 for your total of face cards.

*September 9, 2011*

**Math**

since there is 52 cards in a deck and you know there is 4 of each kind. you just set it as a fraction.

*September 9, 2011*

**Chemistry**

oops...* Assuming no other rxn's what mass of CO2 was produced in this rxn?

*September 9, 2011*

**Chemistry**

You carefully weigh out 19.00 of powder and add it to 76.95 of solution. You notice bubbles as a reaction takes place. You then weigh the resulting solution and find that it has a mass of 88.16 . The relevant equation is CaCO3+2HCl ----> H2O + CO2 + CaCl2 Assuming no other ...

*September 9, 2011*

**Math**

you plug in -8 for r. I -15- (-8) l + l -8 l l -7 l+ l-8 l since you have absolute value bars anything in absolute value turns positive and you take away the bars. soo....... 7+8 =15

*September 9, 2011*

**Scientific Notation**

For scientific Notation, when expressing the number it cannot be greater then10. You usually put the decimal in the tenths spot such as 1.0, 2.0, 3.0 etc. you would imagine that your decimal is at the end of the number and then move your decimal toward the end. the exponent ...

*September 9, 2011*

**Trigonometry**

You draw a triangle and label all of your given information. so you subtract 90 from 38degree35' to get angle A. then you use SOH CAH TOA tan 38degree35'= b/6.434mi to solve for side b. then use cos38degree35' = 6.434mi/c to solve for side c.

*September 9, 2011*

**math**

A: -1/2= 1/2 #: 4 = 1/4 C: 0=0

*September 9, 2011*

**CHEMISTRY!!!!!!! HELP PLEASE:)**

How many kilograms of chlorine are in 24 kg of each of the following chlorofuorocarbons (CFCs)? 1) CF2CL2 express answer using two sig figs how would i solve for this problem??? thanks!

*September 7, 2011*

**Chemistry**

you would use 1 Hz =299792458wavelength meters so using that you would convert kHz to Hz, then Hz to meters. for the radio wave in meters then you would continue using the same conversion as the one above and then convert meters to nanometers using 1m= 1X10^-9 nm. for the last...

*September 7, 2011*

**math**

thats correct.

*September 7, 2011*

**chemistry**

you would divide the grams of each molecule produced by the smallest ratio to find the subscripts.

*September 7, 2011*

**chemistry**

empirical formula is the smallest whole number ratio molecular formula is the empirical doubled i believe.

*September 7, 2011*

**Math**

you would do... combine the i"s and the whole numbers together. (8-4)+(-i+i)= 4

*September 7, 2011*

**PreCal**

Combine the whole numbers and the i's (7+-8) + (-7i+-2i) =-1+-9i

*September 7, 2011*

**mathematics**

Area of what kind of shape? it depends on the shape for the formulas for area. A=pie X r^2 for a square. V= LXWXH so to find your area you would need the radius.

*September 7, 2011*

**trig**

nevermind, figured it out.

*September 6, 2011*