Thursday

January 29, 2015

January 29, 2015

Total # Posts: 301

**Science **

A sample of steam with a mass of 0.530g and at a temperature of 100 ∘C condenses into an insulated container holding 4.40g of water at 5.0∘C.( ΔH∘vap=40.7 kJ/mol, Cwater=4.18 J/g⋅∘C). What is the final temperature of the mixture, assuming no ...
*January 20, 2015*

**maths**

I am fraction they say i m nt proper i may be improper but when u solve me u get number seven my number is 21.wht fraction am i?
*December 25, 2014*

**physics**

A helicopter flies south at 185km/hr relative to the ground. The wind is blowing 60km/hr to the west compared to the ground. What is the helicopter's speed to an observer on the ground?
*December 12, 2014*

**Math**

Yes C is my answer. I'm I correct.
*December 10, 2014*

**Math **

Ken planted 8 flowers and 4 shrubs in his mother's garden. He ran out of fertilizer before he planted 2 of the flowers and 1 of the shrubs, so he planted them without fertilizer. What percentage of plants were planted without fertilizer? A. 12.5% B.25% C. 50% D. 75% My ...
*December 10, 2014*

**physics**

A student fires a rocket at 24 degrees above the horizontal. The 10kg rocket comes out of the gun barrel at 1000 m/s, and accelerates 15 m/s^2 uniformly until it burns out 2 seconds later. It then is acted apon by gravity until it hits the ground. I need to see a drawn out ...
*November 20, 2014*

**Chemistry (urgent)**

1.Using Nerst, find the E of the cell for the dicromate redox system: A.under standard conditions. B.under neutral solutions instead of acid solutions. 2.Use Nerst and the hydrogen half equation to obtain an expression for pH.
*October 29, 2014*

**Chemistry**

1.Using Nerst, find the E of the cell for the dicromate redox system: A.under standard conditions. B.under neutral solutions instead of acid solutions. 2.Use Nerst and the hydrogen half equation to obtain an expression for pH.
*October 29, 2014*

**math**

How many packs of DVDs can you buy with 198 dollars if one pack costs 18 dollars
*October 23, 2014*

**Chemistry (urgent)**

Hydrolysis of a compound A, C7H6cl2 was carried out by refluxing with excess potassium hydroxide solution. the resulting solution was acidified with dilute HNO3 acid and excess silver nitrate was added to precipitate the chloride ions as silver chloride. 0.718g of silver ...
*October 23, 2014*

**alegbra**

This isosceles triangle has two sides of equal length, a, that are longer than the length of the base, b. The perimeter of the triangle is 15.7 centimeters. The equation 2a + b = 15.7 can be used to find the side lengths. If one of the longer sides is 6.3 centimeters, what is...
*October 13, 2014*

**sixth grade math**

3 3/5 * 5/6 = 90/45 Do I have correct answer?
*September 24, 2014*

**sixth grade math**

Multiply. Write each product in simplest form. 1. 2 3/8 * 1 3/5 = 3 4/5 2. 1 5/6 * 2/3 = 11/10 3. 7/8 * 3 1/3 = 35/27 Do I have the correct answers? If not can someone show how to solve them?
*September 17, 2014*

**sixth grade math**

Can somebody please help me?
*September 17, 2014*

**sixth grade math**

Multiply. Write each product in simplest form. 1. 2 3/8 * 1 3/5 = 3 4/5 2. 1 1/5 * 3/5 = 18/25 3. 1 5/6 * 2/3 = 11/10 Do I have the correct answers? If not can someone show me how to solve them?
*September 17, 2014*

**Math**

What is the sum of all the positive numbers smaller than 100,000 where all digits can only be 1 or 0.
*September 11, 2014*

**chemistry 12**

a chemical reaction released 50.0kJ of energy as it heated a sample of water from 17.0 degrees celsius to 75.0 degrees Celsius, what mass of water was heated? I have no clue as to how to do this! can anyone help?
*September 4, 2014*

**chemistry**

How many grams of glycolic acid are needed to react with 30 mL of 0.1 M NaOH?
*July 2, 2014*

**math**

Thanks
*April 27, 2014*

**math**

is 100 over 1000 10%?
*April 27, 2014*

**Math**

Solve: -23m-(-35m)= -48
*March 11, 2014*

**math**

Justin is 10 years less than half his father's age. If Justin is 12 years old, how old is his father?
*March 5, 2014*

**Calc Help :(((((**

Solve it step by step so I can't do the rest. lim x->-infinity (ax^2+b)/(cx+d) Thank you! Answer th
*February 23, 2014*

**Calc Help :(((((**

Solve it step by step so I can't do the rest. lim x->-infinity (ax^2+b)/(cx+d) Thank you!
*February 23, 2014*

**statistics**

Use a table of t-values to estimate the P-value for the specified one-mean t-test. Left-tailed test, n=12, t= -3.412. a=p<0.005. b= p>0.005. c= 0.005<p<0.01.
*February 21, 2014*

**Angle of elevation**

A rocket fired straight up is tracked by an observer on the ground a mile away. a)Show that when the angle of elevation is theta, the height of the rocket in feet is h=5280tan(theta).
*February 6, 2014*

**Angle of elevation**

John stands at 12 feet from the foot of a tree. The angle of elevation to the top of the tree is 60°. What is the height of the tree?
*February 5, 2014*

**health**

What physical symptoms often accompany social phobia? A. Difficulty talking B. Trembling C. Nausea D. All of the above
*December 26, 2013*

**Math**

What is the number of different squares which can be inscribed in a given equilateral triangle?
*December 13, 2013*

**math**

A recipe for cooking a turkey states to allow 15 minutes for each pound of turkey and to add 5 minutes per pound if the turkey is stuffed. Our turkey weights 18 pounds and will be stuffed. It takes half an hour for the turkey to cool. What time should the turkey go in the oven...
*December 1, 2013*

**economics**

What is the opportunuity cost if you make 15 a hour but you decide not to work for a 1 hour and go to the movie which cost 10 what is the opportunity cost?
*November 2, 2013*

**chem**

A 1L flask is filled with 1.25 g of argon at 25 degrees celcium. A sample of ethane vapor is added to the same flask until the total pressure is 1.45 atm. What is the partial pressure of argon in the flask? Chemistry - DrBob222, Tuesday, October 5, 2010 at 9:00pm mols Ar = 1....
*October 24, 2013*

**Quantum Physics**

I bet "Cheaters" don't have answer to this question...
*October 12, 2013*

**Quantum Physics**

Yes, I was trying to say it should be the answer, but the question required 0<=thetha<=pi... this doesn't satisfy for any answers mentioned above by me... I feel this question is tricky... can someone find the answer?
*October 12, 2013*

**Quantum Physics**

8(d) the answer should be thetha = -2*B*t phi = pi/2 I tried thetha = -2*B*t, 2*pi-2*B*t (although this mayn't be always between 0 and pi), 2*B*t (i know its wrong but i tried)
*October 12, 2013*

**Quantum Physics**

8(d) I tried everything... I can't get any value for 0<=thetha<=pi
*October 12, 2013*

**Calculus**

(cos πx + sin πy)4 = 54
*October 9, 2013*

**Calculus**

(cos πx + sin πy)4 = 54; Implicit Differentation
*October 9, 2013*

**Math**

Casper bought some pencils at $.50 each. He had $3 left after the purchase. If he wanted to buy the same number of note pads at $.80 each, he would be short $1.50. Write a linear equation for the number of pencils he purchased. Then solve it.
*September 30, 2013*

**math**

a local summer baseball team plays 20 games each season. so far, they have won 9 games and lost 2. how many more games must they play win this season to win at least 75% of all their games?
*September 21, 2013*

**Chemistry help please**

How many milligram of lysozyme (MW=14,600 g/mol) are needed to make 3 liters of a 10^-6 M solution?
*September 16, 2013*

**Chemistry help needed**

How many milligram of lysozyme (MW=14,600 g/mol) are needed to make 3 liters of a 10^-6 M solution?
*September 15, 2013*

**Chemistry**

How many milligram of lysozyme (MW=14,600 g/mol) are needed to make 3 liters of a 10^-6 M solution?
*September 15, 2013*

**Chemistry**

Thanks!
*September 15, 2013*

**Chemistry**

How man moles of sodium phosphate are there in 0.4 liters of 0.1M Na2HPO4 (MW=141.96 g/mol)? 2.) How many millimoles in 200 ml?
*September 15, 2013*

**Physics**

I am confused, selenium Se, is on the periodic table, but does it combine with other elements on the periodic table? I want to say no because it is a gas. Is that correct.
*August 28, 2013*

**math - geometry**

Austin wants to sketch the graph of a circle represented by the given equation. (x - 4)2 + (y + 7)2 = 64 Using complete sentences, describe the steps used to sketch the circle on a coordinate grid
*August 19, 2013*

**ap chemistry**

BaO2(s) + 2 HCl(aq) H2O2(aq) + BaCl2(aq) What amount of hydrogen peroxide should result when 1.00 g of barium peroxide is treated with 15 mL of hydrochloric acid solution containing 0.0330 g of HCl per mL? So confused... >.<
*August 1, 2013*

**CHEMISTRY**

Bacterial digestion is an economical method of sewage treatment. 5CO2(g) + 55NH4+(aq) + 76O2(g) right arrow Bacteria C5H7O2N(s) + 54NO2-(aq) + 52H2O(l) + 109H+(aq) bacterial tissue The above reaction is an intermediate step in the conversion of the nitrogen in organic ...
*August 1, 2013*

**chemistry**

Nitric acid is produced commercially by the Ostwald process, represented by the following equations. 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) 2 NO(g) + O2(g) 2 NO2(g) 3 NO2(g) + H2O(l) 2 HNO3(aq) + NO(g) What mass in kg of NH3 must be used to produce 4.4 multiplied by 106 kg HNO3...
*August 1, 2013*

**AP CHEMISTRY**

Thank you so much!
*August 1, 2013*

**AP CHEMISTRY**

Okay, it needed four sig figs. the next part of the question is: How could this result be checked without changing the above procedure? What does this mean?
*August 1, 2013*

**AP CHEMISTRY**

i understand where my mistake was. when i went to find the %Cu i did: 100%-8.98%= 91.02 (rounding to three sig figs would give me 91.0) both those answers were wrong on the on the online grader
*August 1, 2013*

**AP CHEMISTRY**

I found the mass of ZnCl2 to be 136.29g I started out: .0953/136.3= 6.9e-4 then I did: 6.9e-4 x 65.39= .046 and multiplied that by a hundred
*August 1, 2013*

**AP CHEMISTRY**

Commercial brass, an alloy of Zn and Cu, reacts with hydrochloric acid as follows. Zn(s) + 2 HCl(aq) ZnCl2(aq) + H2(g) (Cu does not react with HCl.) When 0.5093 g of a certain brass alloy is reacted with excess HCl, 0.0953 g ZnCl2 is eventually isolated. (a) What is the ...
*August 1, 2013*

**ap chemistry**

Thank you very much!
*August 1, 2013*

**ap chemistry**

so is the answer 171 g F2? I did: 4.5 mol F2 x (38 g/1mol) =171g
*August 1, 2013*

**ap chemistry**

the balanced equation is P4+6F2-->4PF3 so i have: 3.01mol PF3 x (6 molF2/4molPF3)=4.5mol2F2 So then i convert it to grams, correct?
*August 1, 2013*

**ap chemistry**

265.66g x (1mol/88) = 3.01 mol PF3 correct?
*August 1, 2013*

**ap chemistry**

i got 88 mol. is that right?
*August 1, 2013*

**ap chemistry**

Consider the following unbalanced reaction. P4(s) + F2(g) PF3(g) How many grams of F2 are needed to produce 212 g of PF3 if the reaction has a 79.8% yield? I did 212/.798=265.66 grams do I convert that to moles next?
*August 1, 2013*

**chemistry**

Consider the following unbalanced reaction. P4(s) + F2(g) PF3(g) How many grams of F2 are needed to produce 212 g of PF3 if the reaction has a 79.8% yield?
*August 1, 2013*

**chemistry**

What mass in kg of NH3 must be used to produce 4.4 multiplied by 106 kg HNO3 by the Ostwald process, assuming 100% yield in each reaction?
*August 1, 2013*

**chemistry**

What mass in kg of NH3 must be used to produce 4.4 multiplied by 106 kg HNO3 by the Ostwald process, assuming 100% yield in each reaction?
*August 1, 2013*

**chemistry**

You have a chemical sealed in a glass container filled with air. The glass container has a mass of 200.0 grams and the chemical has a mass of 800 grams. The total mass of the set-up is 1000 grams. The chemical is ignited by means of a magnifying glass focusing sunlight onto ...
*August 1, 2013*

**math**

Q1: If K=In a -In b +In c -t/bc,show that K=(ac/b)e^(-t/bc). Q2:Express log(8)5 in terms of m ,where m=lg 2 Q3:Given that log (4)3 =a and log(4)5 =b ,express log(75)16 in terms of a and/or b . really dont know how to do these qns..please help ! thanks a lot
*July 18, 2013*

**math**

express y=0.1(1000)^x in the form lg y =mx+c ,where m and c are constants ,and x is a function of x . Determine the constants m and c and the function x .
*July 18, 2013*

**math**

evaluate without using a calculator [log(5)4 x log(2)10 ]/ [log(25)√10]
*July 18, 2013*

**Chemistry**

List in increasing order of expected Rf values in a TLC experiment: salicylic acid, toluene, and benzophenone.
*July 1, 2013*

**Chemistry!!! **

1.)The silica that makes up the stationary phase in TLC chromatophraphy is more polar than the mobile phase. What then might the relative positions of the analgesics on the developed TLC plate tell you about the polarity of these molecules? Does this match the expectations ...
*July 1, 2013*

**math**

Sams shoes makes a profit of 38$ on every pair of athletic shoes it sells. How many pairs of shoes must Sam sell to earn a profit of 950?
*June 30, 2013*

**chemistry **

Zn(s) + 2AgNO3(aq) = 2Ag(s) + Zn(NO3)2 (aq) It would require_____g of zinc to produce 5.40g of silver.
*June 12, 2013*

**english**

i need help with my ode poem about mom
*May 29, 2013*

**math**

a 5700 year old bone has 10 c14 atoms. how much c 14 did it have originally?
*May 28, 2013*

**math**

The quotient of p and 5.
*May 28, 2013*

**chem**

Given an aqueous solution in which the [H+] = 2.5EE-7 M, what is the molar hydroxide ion concentration
*May 5, 2013*

**Calculus**

A right circular cone has a constant slant height of 12 feet. Find the radius of the base for which the cone has maximum value
*May 4, 2013*

**Math**

Can you explain why it is yes... Pls.,
*April 23, 2013*

**Math**

On a map John is standing at (11,11). His friend Lucy is standing at (1,11). John took 10 steps to the right. Is he standing with Lucy now?
*April 23, 2013*

**Algebra**

2 questions I need some help with please! 1. Find the partial sum S5. an= -2n+16 2.Solve the system by triangularizing the augmented matrix and using bakc substitution. 7x=y-6 3y= -5-2x
*April 17, 2013*

**Algebra**

I need some help! Determine whether infinite geometric series has a finite sum. If so, find the limiting value. 112+56+28+....
*April 16, 2013*

**Algebra**

I need some help! Determine whether infinite geometric series has a finite sum. If so, find the limiting value. 112+56+28+....
*April 16, 2013*

**Literature**

In I Am Nujood, The urban elites Nujood encounters in the courtroom and at the Yemen Times lead very different lives from those of Nujood and the country people of Yemen. How are these “enlightened” people actually disconnected from the rest of their society? For ...
*April 16, 2013*

**Literature**

In I Am Nujood, what enables Shada to take up Nujood’s cause so quickly and effectively? How does Shada, whom Nujood calls her “second mother,” open up Nujood’s world? Who else teaches Nujood about what a “real” family can be like?
*April 16, 2013*

**Literature**

In I Am Nujood, Nujood says that when her family was driven from Khardji, they lost “a small corner of paradise.” How do the injustices endured by Nujood’s father and brother, Fares, show that life in a patriarchal society can be hard not just for women, but for...
*April 16, 2013*

**Math**

I need some help. A biologist finds that the population of a certian type of bacteria double seach half-hour. An initial culture has 60 bacteria. 1. What is the population after 3 hours? 2. How long will it take for the number of bacteria to reach 983,040?
*April 9, 2013*

**Algebra Recursive sequence help**

I need some help as I'm totally lost! I need to find the first five terms of each recursive sequence. The n-1 on the problem shows it below the a. 1. A1=3 An=2a n-1- 3 2. C1=64, C2=32 Cn= Cn-2 - Cn-1/2
*March 31, 2013*

**Algebra Multiple Choice help!!**

I need help with these! I got B for 1. C for 2. and D for 3. Thanks for the help! 1.) Find the values of a, b, and c that will make the statement true. [5 a -2] [5 102] [3 4 –b] = [-3 -4 3] [2c 5 9] [-2 5 9] a.) 8R1-R2--> =R2 b.) -8R1-R2 -> =R2 c.) –8R1 +R2 -&...
*March 28, 2013*

**Algebra Multiple choice!!! Help**

1.) Find the values of a, b, and c that will make the statement true. [5 a -2] [5 102] [3 4 –b] = [-3 -4 3] [2c 5 9] [-2 5 9] a.) 8R1-R2--> =R2 b.) -8R1-R2 -> =R2 c.) –8R1 +R2 -> =R2 d.) 8R1-R2 -> =R2 2.) Solve the system by triangularizing the augmented ...
*March 28, 2013*

**Algebra Multiple choice revised!! HELP**

I have a few questions I need help with! Please explain if my answer was not right how you got to it. I got 1.) B 2.) A 3.) C 1. Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in ...
*March 28, 2013*

**Algebra help needed please!!**

I have a few questions I need help with! 1. Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in terms of a parameter. -3x+y-z=-4 6x-2y+2z=8 -12x+4y-4z=-16 2. Solve the system by ...
*March 28, 2013*

**Algebra Multiple Choice**

Hello, This is the last of questions I have for my practice assignment. Again I will put what I got. Thanks for your help. 1.) Solve the system using substitution. Write answer as an ordered pair. 4x+2y=8 -5x-2=y A.) First equation (-2,8) B.) Second equation (-2,8) I put A 2...
*March 21, 2013*

**Algebra-Multiple choice**

Hello, I have some practice math I'm working through and I'm unsure about the answer. I will also put what I got. Thanks for the help. 1. Solve using any method and identify the system as consistent, inconsistent, or dependent. -2x+y=8 2x+2y=-8 A.) (-4,0); consistent/...
*March 21, 2013*

**maths**

I think that what they mean is to lay out something to count the number, they give you the number 5, find something (beans, legos, something) to act as a counter. Use those counters to count to the number 5, or the number 3, use more counters to count above those numbers. ...
*March 10, 2013*

**GEN CHEM**

A solution of CaCl2 is prepared by dissolving 1.004 g of the solid in approximately 30 mL of water. How many moles of CaCl2 does this solution contain?
*March 3, 2013*

**4th grade math**

Instead of having an "x" for multiplying, the "*" represents multiplication as well. So 93 times 18. The answer would then be 1,674. Hope I helped!
*January 30, 2013*

**Chemistry**

Describe how proteins are manufactured in the ribosomes (include discussion of codons and anti-codons).
*December 19, 2012*

**Chemistry**

I understand but I thought maybe someone could explain it.
*December 19, 2012*

**math**

If x,y,p,q are points on the circle with radius 6 and xp=yq what is pq? I think the answer is cannot be determined Thanks.
*December 3, 2012*

**CHEMISTRY**

WHAT IS THE PH OF 0.50 M HC10? KA OF HC10 IS 3.5X10-8
*December 3, 2012*