Friday

March 6, 2015

March 6, 2015

Total # Posts: 931

**Chemistry**

Please help! I have 30 ml bottle of 5% hydrocholric acid. Ned to dillute to make 200 ml of .01 M hydrocholric acid. I dont know how much of the bottle solution to add to how much distilled water to get 200 ml at .01 M
*March 4, 2015*

**Chemistry**

5% hydrocholric acid in 30ml (1 fl oz) - how to dillute to make 200 ml of .01 M? I think i need to first fin concentration solute /amount of solution x 100 .05/30 x100 = .166 Then i get lost!
*March 4, 2015*

**math**

An airplane travels with a speed of 145 mph in calm air. the wind is blowing with a velocity of 23 mph from N72degreesE. If the plane is headed in a direction N63W, find the magnitude of the speed and the direction of the airplane with reference to the ground. In what ...
*February 24, 2015*

**physics**

i forgot to square the whole set of numbers. u=.5mv^2 and then u=qV
*February 22, 2015*

**physics**

A proton has an initial speed of 7·105 m/s. It is brought to rest by an electric field. a.) What is the magnitude of the voltage difference needed to bring this charge to rest? answer: 365.313*7v, WHY
*February 22, 2015*

**Physics**

A projectile on level ground is launched with a certain speed vi and has a downrange distance of vx what is its new downrange distance if it is launched with a speed of 4vi instead?
*February 19, 2015*

**Physics**

A man is on his apartment balcony 25m above ground level. He has a fire hose aimed directly at another man who is a ground level, a horizontal distance of 35m from the apartment block. The man on the balcony opens the nozzle and water travels with a speed of 18m/s. how far ...
*February 18, 2015*

**Math**

Do i need to replace x to a number? or the question just asking to explain how x can become that equation like your answer ? if x = 0 , 9^x = 1 if x is positive, 9^x > 1 if x is negative 9^x < 1 There is no value of x which makes 9^x = 0 nor can 9^x ever be < 0
*February 8, 2015*

**Math**

identify the conditions on x that make the following statement true, if they can be made true at all: 9^x > 1 9^x < 1 9^x = 1 9^x = 0 9^x < 0 what is the question asking for?
*February 8, 2015*

**Science**

a child mass m slides down a slide 5 m high. the child speed at the bottom of the slide is 3 meters per second. what is the percent of mechanical energy the child has at the top of the slide. converted to kinetic energy
*February 7, 2015*

**math**

You have 100 feet of fencing with which to construct a circular pen. what is the area can you enclose?
*February 5, 2015*

**Math**

An open box is to be made from a flat piece of material 9 inches long and 6 inches wide by cutting equal squares of length x from the corners and folding up the sides. Write the volume Vof the box as a function of x. Leave it as a product of factors, do not multiply out the ...
*January 22, 2015*

**math**

SA = 6 (4.5 cm)^2 = 4.5cm^2 = 20.25cm^2 20.25cm^2*6= 121.5 cm^2
*January 20, 2015*

**Math**

1 mile = 5,280 ft. 5,280 ft. * 15 miles = 79,200 ft.
*January 20, 2015*

**algebra**

It's been a minute since I have done much with algebra, but if you are looking to simplify I believe this is correct. First part cancels out so (b+c+a) / (b+c+a) = 1 Then you can remove the squares by dividing like variables. (1 + (b^2 + c^2 - a^2)) / (2*b*c) = (1 + b + c...
*January 20, 2015*

**Physics 152**

I was able to come up with the answers through trial and error, and the answer for the charge +q makes sense, but I don't understand why the answer for the -q is correct. Please help. A positive point charge +q1, a second point charge q2 that may be positive or negative, ...
*January 20, 2015*

**math**

Two is C. You can multiply any number by the decimal equivalent of the percentage you are interested in (i.e. 40% if 50 is 0.4 * 50) First one has me confused. Are they typed in correctly? 15% of 30 is 4.5 A. 15/30 = x/100 15/30 = 0.5, .5/100 = 0.005 Wrong B. 15/100 = x/30 15...
*January 20, 2015*

**Math (calculus)**

If y = 2x^3 - 4x and dx/dt = 4, find dy/dt when x = 1. Please show me how to solve this problem with steps.
*January 10, 2015*

**Accounting**

On Sept. 1, 2012, Parsons Company purchased $84,000 10 year 7% government bonds at 100 plus accrued interest. The semi-annual interest payment dates are June 30 and Dec. 31. Journalize the entry to record the bond purchase.
*January 8, 2015*

**Chem**

So I corrected my errors but am still confused. Should I convert torr to ATM or KPa to get R?
*December 18, 2014*

**Chemistry**

Ok thanks for your help!
*December 17, 2014*

**Chemistry**

Oxygen gas can be generated by heating KClO3 in the presence of a catalyst. KClO3 KCl + O2 (unbalanced) What volume of O2 gas will be generated at T = 35°C and P = 764.0 torr from 1.51 g of KClO3? I got .414 L and used 22.4 L for moles of O2 What's going on??
*December 17, 2014*

**Stats**

Consumption of alcoholic beverages by young women of drinking age has been increasing in the United Kingdom, the United States, and Europe (The Wall Street Journal, February 15, 2006). Data (annual consumption in liters) consistent with the findings reported in The Wall Street...
*December 16, 2014*

**Calculus**

Find the derivative of 1/(1+(x-3)^2) Steps would be appreciated.
*December 15, 2014*

**Physics**

In an electricity experiment, a 0.900g plastic ball is suspended on a 50.0cm long string and given an electric charge. A charged rod brought near the ball exerts a horizontal electrical force F⃗ elec on it, causing the ball to swing out to a 23.0∘ angle and remain ...
*December 15, 2014*

**Trig**

Jane has a bike with a 22-inch rear wheel. The wheel sprocket is 3 inches in diameter and the pedal sprocket is 4 inches in diameter (the sprockets hold the chain.) How fast in miles per hour is she going if she pedals at a rate of 100 revolutions per minute?
*November 17, 2014*

**science**

thanks
*November 17, 2014*

**science**

if you get cut a type of metal in two pieces do they both have the same density
*November 17, 2014*

**Geometry**

What is the formula for finding the central angle of a sector when given the radius and arc length?
*November 11, 2014*

**physics**

A 1.2 lead ball is launched off a cliff top at 16 m/s Determine the balls kinetic energy at position P. Ignore friction
*November 6, 2014*

**chemistry**

I am not understanding what you are saying? So what would be the answer? Li is a solid and Fe(NO3)3 is aqueous
*November 3, 2014*

**chemistry **

Not sure how to complete this chemical reaction: Li + Fe(NO3)3 --->
*November 3, 2014*

**Chi-Test explaination**

Can someone explain how to conduct a Chi-test in depth?
*October 13, 2014*

**Math**

Question If there is a Part B. Like Using the following information: B(s)--B(aq) Delta H=+23.8 KJ/mole 2B(aq)---A (aq) Delta H= -1.25 KJ/mole Calculate ÄH°rxn for the following reaction (in kJ/mol). A(s)---2B(s) How exactly would you do that?
*October 5, 2014*

**physics**

Three forces act on a moving object. One force has a magnitude of 62.6 N and is directed due north. Another has a magnitude of 45.9 N and is directed due west. What must be (a) the magnitude and (b) the direction of the third force, such that the object continues to move with ...
*October 3, 2014*

**Math**

Mr Kim mix cement and sand to make a mixture.He uses 2 pails of cement for every 5 pails of sand. (A) Find the ratio of the number of pails of cement to the number of pails of sand. (B) If he uses 24 pails of cement,how many pails of sand does he use? (C) If he uses 35 pails ...
*October 2, 2014*

**Physics-Intro**

Find the total force necessary to give a rocket of mass 25,000 slugs an acceleration of 28.0 ft/s2.
*September 30, 2014*

**computers**

Is there a way to find out some information about an e-mail address without actually sending a message? As in, is it still in active use? Or, who is the person using it?
*September 29, 2014*

**physics**

A sprinter starts from rest and accelerates for 5s. He then travels at a constant velocity for 10s. Finally he slows down to a stop in 5s. Draw a distance time graph to represent his motion.
*September 17, 2014*

**Physics please help**

So i just find the slope of the curve
*September 16, 2014*

**Physics please help**

How do I convert a distance time graph into a velocity time graph. I am given a distance time graph with three curves but i am not sure how to calcualte the area of them to get the velocity time graph.
*September 16, 2014*

**Physics**

Heather and Jerry are standing on a bridge 43m above a river. Heather throws a rock straight down with a speed of 12m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance.
*September 11, 2014*

**English**

In wuthering heights, what are the most influential forces in the shaping of a childs values and behaviour? Parents, guardians, or other family members?schooling? Friends? I think the answer would be parents, guardians or other family members
*September 9, 2014*

**Biology please help!**

Is respiratory control more sensitive to small changes in arterial PO2 or in arterial PCO2
*September 8, 2014*

**English**

What role, according to Dessner, does irony play in the story A&P by John Updikes? What levels of irony are at work in the story? For example, what does he identify as " charming irony" as compare to " deeper irony"? Explain
*August 30, 2014*

**Health Part 2**

Thank you much Ms Sue
*August 18, 2014*

**Chemistry**

Using Hess’s Law with the following data: N2(g) + O2(g) = 2NO(g) Del(H) = 180.7kj 2NO(g) + O2(g) = 2NO2(g) Del(H)= -113.1kj 2N2O(g) = 2N2(g)+ O2(g) Del(H)=-163.2kj Calculate Del(H) for the reaction: N2O(g) + NO2(g) = 3NO(g)
*July 29, 2014*

**Chemistry**

Calculate the value of the standard enthalpy change for each of the following reactions (standard enthalpy for Na2SO4(s) is -1375.653 kj/mole): a)4HBr(g) + O2(g) = 2H2O(I) + 2Br(I) b)2Na(OH)(s) + SO3(g) = Na2SO4(s) + H2O(g) c)CH4(g) + 4CI2(g) = CCI4(I) + 4HCI(g) d)Fe2O3(s) + ...
*July 3, 2014*

**Chemistry**

Using standard enthalpies information, calculate the standard enthalpy change for this reaction. a)(thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b)Mg(OH)2(s) = MgO(s) + H2O(I) c)N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d)SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)
*July 3, 2014*

**Chemistry**

Given the Data: N2(g) + O2g) = 2NO(g) delta H = 180.7kj, 2NO(g) + O2(g) = 2NO2(g) delta H = 0113.1kj, 2N2O(g) = 1N2(g) + O2(g) delta H = -163.2kj. Using Hess’s Law calculate delta H for the reaction: N2O(g) + NO2(g) = 3NO(g)
*July 3, 2014*

**Chemistry**

A solution of hydrogen peroxide, H2O2, is titrated with potassium permanganate, KMnO4, according to the following equation: 5H2O2 + 2KMnO4 + 3H2SO4 = 5O2 + 2MnSO4 + 8H2O + K2SO4. It requires 46.0 mL of 0.145 Mol/L KMnO4 to titrate 50.0 mL of the solution of H2O2. What is the ...
*July 3, 2014*

**music**

I think your ideas are great,but you need to decide together. Why don't you talk to them and negotiate the correct song to fit with you. Find a time at school, after school, at a dance studio or all of them. It is great to practice and practice does make perfection. If ...
*June 7, 2014*

**Math**

Please help, I don't understand.
*May 23, 2014*

**Math**

What is the degree of the monomial? 6x^5
*May 23, 2014*

**Physics**

1.How are alternating and direct current different? 2.Who invented direct current? 3.Who invented alternating current? 4.What are some of the advantages of alternating current? 5.Do all devices that plug into the wall run on alternating current? Why/why not? 6.What is the ...
*May 20, 2014*

**chemistry**

20 mL of 0.125 M potassium iodide solution is mixed with 10 mL of 0.1 g L–1 sodium thiosulfate solution and 0.2 g of solid iodine indicator is added. To this solution is added 20 mL of 0.025 M peroxodisulfate solution. After 46 seconds a blue colour appears, indicating ...
*May 9, 2014*

**PHYSICS HELP**

A long, ideal solenoid has a diameter d=12cm and n=1200turns/meter carrying current I=20A. If the current is lowered at 4.33amp/s to zero, what is the magnitude of the induced electric field in V/m at a position 8.2cm from the solenoid's axis
*April 8, 2014*

**Physics**

If an object has a work of 300J and a displacement of 20m, how would I determine the net force?
*April 4, 2014*

**chemistry**

Plan how you would make 100mL of a buffer solution with a pH of 10.80 to be made using only sodium carbonate, sodium hydrogen carbonate and water. You should specify the amount of sodium carbonate and sodium hydrogen carbonate that you would use. Below is what i got up to then...
*April 4, 2014*

**chemistry/science**

Not sure if i posted this but Need help with my pH calculations? 0.10 mol of solid sodium hydrogen carbonate and 0.20 mol of solid sodium carbonate are dissolved in the same beaker of water, transferred to a volumetric ﬂask and made to 250.0 mL. The Ka for HCO3 – ...
*April 4, 2014*

**chemistry**

Need help with my pH calculations? 1) 0.10 mol of solid sodium hydrogen carbonate and 0.20 mol of solid sodium carbonate are dissolved in the same beaker of water, transferred to a volumetric ﬂask and made to 250.0 mL. The Ka for HCO3 – is 4.7 x 10–11. a) ...
*April 4, 2014*

**Physics**

A satellite is given a boost of 540 MJ of energy to move it from its initial orbit at an altitude of 150 km to a higher altitude orbit. If the satellite has a mass of 1.16 ✕ 10^3 kg, what is the new altitude it reaches? Take the mass of the Earth to be 5.97 x 10^24 kg ...
*April 2, 2014*

**Physics-Gravitational Potential Energy**

A satellite is given a boost of 540 MJ of energy to move it from its initial orbit at an altitude of 150 km to a higher altitude orbit. If the satellite has a mass of 1.16 ✕ 103 kg, what is the new altitude it reaches? Take the mass of the Earth to be 5.97 x 10^24 kg ...
*April 1, 2014*

**Physics**

A snowmobile, with a mass of 530 kg, applied a force of 410 N backwards on the snow. a) What force is responsible for the snowmobile’s resulting forward motion? (Hint: Think action–reaction force pairs.) b) If the force of friction on the snowmobile is 187 N ...
*March 28, 2014*

**Physics( Explain and choose right answer) **

A ball on the end of a rope is moving in a vertical circle near the surface of the earth. Point A F T is at the top of the circle; C is at the bottom. Points B and D are exactly halfway between A and C. Which one of the following statements concerning the tension in the rope ...
*March 24, 2014*

**Physics( Explain and choose right answer) **

A 3 kg cat sitting on a 1.5 kg piece of cardboard on a frozen lake wants to jump to shore without touching the ice. If there is no friction between the cardboard and the ice, when the cat jumps. the cardboard will move in the opposite direction with a velocity: A. half as ...
*March 24, 2014*

**Chem**

The density of ethanoic anhydride is 1.092 g/mL. Use this value, and the amount that you used in the laboratory to show that ethanoic anhydride is in excess for your preparation of ASA?, 2.5ml of ethanoic anhydride was used.
*March 14, 2014*

**English**

Which implicit element of the analogy in these lines is analogous to "family worship"? Breakfast over, Aunt Polly had family worship: it began with a prayer built from the ground up of solid courses of Scriptural quotations, welded together with a thin mortar of ...
*March 6, 2014*

**Please help with Chemistry?????**

5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the mixed ...
*February 26, 2014*

**Please help with Chemistry?????**

A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
*February 26, 2014*

**Chemistry**

A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
*February 26, 2014*

**Chemistry**

5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the moxed ...
*February 26, 2014*

**Math**

Interest is a concept familiar to most people: every credit card in existence has a term called annual percentage rate (APR), which is an interest rate. Suppose you charged $1,000 to a credit card that has a minimum payment each month equal to the interest owed. Can you figure...
*February 18, 2014*

**Math**

The formula for simple interest is where I is the amount you will pay in interest, r is the rate at which interest will accrue, P is the principal (amount borrowed), and m is the number of times the interest is applied. To solve for the interest rate of your credit card, you ...
*February 18, 2014*

**Math**

Gabe is the human resource manager for the Advanced Scientific Research Lab. He has to record the heights (in centimeters) and weights (in pounds) for each of the scientists in the lab. Height distribution (cm): 178, 163, 174, 186, 154, 167, 167, 181, 159, 165, 177, 191, 158 ...
*February 18, 2014*

**AP chem**

Mostly just setting up my reaction to use for each problem
*February 5, 2014*

**AP chem**

Consider the titration of 50.00 ml .250 M HBr with .100 M Ba(OH)2. What is the pH after the following additions of Ba(OH)2 to the 50 ml of hydrobromic acid? 0 ml. 15 ml. 25 ml. 50ml. 51ml.
*February 5, 2014*

**programming**

using pseudocode debug the following 3 programs // A high school is holding a recycling competition // This program allows a user to enter a student's // year in school (1 through 4) // and number of cans collected // Data is entered continuously until the user wants to ...
*January 13, 2014*

**Physics**

I got it!!! Thank you!!!
*December 24, 2013*

**Physics**

I dont understand it, can you please explain it to me?.. Thanks
*December 24, 2013*

**Physics**

I think it is. and it's not one person, we study in a group. Thank You.
*December 24, 2013*

**Physics**

A pilot, whose mass is 91.0 kg, makes a loop-the-loop in a fast jet. Assume that the jet maintains a constant speed of 125 m/s and that the radius of the loop-the-loop is 0.478 km. What is the apparent weight that the pilot feels (i.e., the force with which the pilot presses ...
*December 24, 2013*

**Physics**

Thank you so much Elena!!
*December 24, 2013*

**Pre-Calc**

Using the difference for formula, find the tan 255. Step by step would be appreciated
*December 18, 2013*

**Math Quiz**

Math Quiz please help fast Write the following ratio in simplest form: 32 min:36 min (1 point) 8:9 8:36 32:9 128:144 2. Marie saved $51. On Wednesday, she spent $8 of her savings. What ratio represents the portion of her total savings that she still has left? (1 point) 43:8 8:...
*December 12, 2013*

**Maths**

Will it be 16x^2-40x+25
*November 18, 2013*

**Maths**

(4x-5)^2
*November 18, 2013*

**Maths**

(5x+4)(5x-4)=
*November 18, 2013*

**physics**

You apply a potential difference of 5.00 V between the ends of a wire that is 2.65 m in length and 0.654 mm in radius. The resulting current through the wire is 17.6 A. What is the resistivity of the wire?
*October 20, 2013*

**Math**

Carla and Candice left from the same place at the same time and rode their bikes in the same direction along a straight road . Candice biked at an average speed that was three-quarters of Carla's average speed. After 2 hours they were 28 miles apart. What was the average ...
*October 7, 2013*

**Math**

The area of each trapezoid is 3 times the area of one triangle. The area of one triangle is six square units. What is the total area of the figure in square units?
*September 23, 2013*

**Algebra word prob**

If you graph the table of values and draw a line through the coordinates, the graph will look like a parabola. Thus the equation is quadratic. Since you don't have a graphing calculator, I will give you the resulting a/b/c values that it comes up with, but the rest is for ...
*September 10, 2013*

**Math**

2. True or false. Suppose the slope of a straight line L is -3/4 and P is a given point on L. If Q is a point on L lying 2 units to the right of P, then Q is situated 3/2 units below P. Prove why.
*August 27, 2013*

**physics **

The Hyperloop is a hypothetical new fast transport system between cities, which works by launching pods that carry people through a very low air pressure tunnel. The Hyperloop reduces friction between the pods and the tunnel by supporting the pod on a cushion of air. This air ...
*August 22, 2013*

**Statistics**

Hola ¿Cuál es el P - value en este problema que escribiste?
*July 29, 2013*

**Math**

A circle of radius 1 is drawn in the plane. Four non-overlapping circles each of radius 1, are drawn (externally) tangential to the original circle. An angle γ is chosen uniformly at random in the interval [0,2π). The probability that a half ray drawn from the centre...
*June 24, 2013*

**Math**

There are 100 runners, each given a distinct bib labeled 1 to 100. What is the most number of runners that we could arrange in a circle, such that the product of the numbers on the bibs of any 2 neighboring runners, is less than 1000?
*June 23, 2013*

**Math**

γ is a permutation on eight elements, though you are not told which permutation it is. If γ is applied to an 8-element set, what is the minimum number of additional times we must apply γ to the resulting set in order to guarantee the set is back in its original ...
*June 18, 2013*

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