Sunday

January 22, 2017
Total # Posts: 1,296

**Algebra**

I still don't understand?

*November 13, 2010*

**Algebra**

One canned juice is 20% orange juice: another is 10% orange juice. How many liters of each should be mixed together in order to get 10L that is 13% orange juice.How many liters of the 20%? How many liters of the 10%?

*November 13, 2010*

**math**

how many 10s are in 1,000?

*November 11, 2010*

**Chemistry**

Ethanol burns to produce 1300.0 kJ/mol and has a heat capacity of 65.6 J/mol·K. If Dr. Porter has 1.00 L of liquid ethanol (density = 0.789 g/mL), what is the minimum mass of fuel that should be removed and burned to heat the remaining ethanol from 25 °C to 90 °...

*November 9, 2010*

**Chemistry**

Hydrofluoric acid etches glass by reacting with the silica in it according to the following equation. H° = 54.5 kJ and S° = 436.5 J/K Calculate G° at 25°C for this reaction.

*November 9, 2010*

**Physics**

Newton's third law says that for every action there is an opposite and equal reaction. Does that mean that the the average thrust force the gas exerts on the engine and rocket would each be 5 N?

*November 7, 2010*

**Physics**

A typical model rocket engine exerts an average force of 5 N on its exhaust gas. How much average thrust force does the gas exert on the engine and rocket?

*November 7, 2010*

**Chem**

2 H2O (l) → 2 H2 (g) + O2 (g) Using the thermodynamic values to calculate accurate values of ΔHr and ΔSr, will the reaction be product favored at high temperature? Why? r stands for reaction

*November 5, 2010*

**Chem. only regarding formula.**

how do do calculate ΔHr and ΔSr?

*November 5, 2010*

**Chem. thankss!!!**

1.0 mol of water (c=4.184 J/g.oC), 1.0 mol of ethanol (c=2.46 J/g.oC), 1.0 mol of carbon tetrachloride (c=0.861 J/g.oC), and 1.0 mol of ethylene glycol (c=2.42 J/g.oC) at 50oC were each placed into a separate coffee cup calorimeter and the temperature recorded. The temperature...

*November 5, 2010*

**Chem**

In an experiment 50 g of a metal was heated to 100oC and placed in 200 g of a liquid at 25oC. Which of the following combinations of metal and liquid will produce the largest temperature increase in the liquid? (Assume that there is no energy transfer to the surroundings.) ...

*November 5, 2010*

**CHEM.**

Zinc is often used to calibrate calorimeters because it undergoes a very sharp phase transition from the solid to the liquid at 419.5oC. Calculate the enthalpy change when 5 g of zinc metal is heated from 100oC to the point where the entire sample is melted. (The heat of ...

*November 5, 2010*

**CHEM. help please**

Consider a system of 3 molecules, A, B, and C. Suppose the 3 units of energy can be distributed over the three atoms where each atom can have no energy, one unit, two units or 3 units of energy. Assume each of the 10 possible arrangements is equally probable. What's ...

*November 5, 2010*

**Chem Help please**

Consider a system of 3 molecules, A, B, and C. Suppose the 3 units of energy can be distributed over the three atoms where each atom can have no energy, one unit, two units or 3 units of energy. Assume each of the 10 possible arrangements is equally probable. What's ...

*November 5, 2010*

**Calculus**

Given the demand function q=173-5p, determine the price where demand has unit elasticity.

*November 4, 2010*

**Calculus**

Given the demand function q=173-5p, determine the price where demand has unit elasticity.

*November 4, 2010*

**Calculus**

the demand for ground chuck(hamburger) in a certain region of the US is given by q= 3.41p^-0.22. is the demand for ground chuck elastic or inelastic

*November 4, 2010*

**Calculus**

a local office supply store has an annual demand for 50,000 cases of photocopier paper per year. it costs $2 per year to store a case of photocopier paper, and it costs $50 to place an order. Find the optimum number of cases of photocopier paper per order

*November 4, 2010*

**CHemistry**

Use the bond energies given in the "Bond Energy" table (can be gained from google) to estimate the delta Ho for the reaction given below. 2ClF3(g) + 2O2(g) Cl2O(g) + 3OF2(g) I did this: 1530 + 996 - (410 + 570) = 1546. But the answer was wrong. I don't know where...

*November 2, 2010*

**Chemistry**

Use the bond energies given in the "Bond Energy" table (can be gained from google) to estimate the delta Ho for the reaction given below. 2ClF3(g) + 2O2(g) Cl2O(g) + 3OF2(g) I did this: 1530 + 996 - (410 + 570) = 1546. But the answer was wrong. I don't know where...

*November 2, 2010*

**Chemistry- helpp!**

The equation for synthesis of the poisonous gas COCl2 is CO(g) + Cl2(g)COCl2 If 43.2 kJ of energy is evolved when 39.5 g of COCl2 is synthesized, what is the molar enthalpy for this synthesis? THANK YOU!

*November 2, 2010*

**Chemistry**

Calculation of the sodium chloride (NaCl) content and evaporation: 1. The amount of sodium chloride in the original mixture may be determined indirectly by adding the masses of ammonium chloride and sand together and subtracting the sum from the initial sample mass of 10g. 2. ...

*October 23, 2010*

**Chemistry**

I am doing a lab online and have no clue on how to get started with the following questions? Please Help me! 1. Calculate and record the following (in grams): (a) mass of NaCl by subtraction of other components: (b) measured mass of NaCl after boiling away water: 2. Calculate ...

*October 23, 2010*

**chemistry**

What volume (in Liters) of hydrogen must react to form 17.0L of ammonia according to the following balanced equation: N2(g) + 3H2(g) --> 2NH3(g) Ratio from equation is H : NH3 = 3 : 2 = 3/2 : 1 = 17x3/2 : 17 = 25.5 : 17 17 L of hydrogen can you check my work is this right?

*October 17, 2010*

**college chemistry**

so it would be (1)(.0036)=n(.0821)(273)?

*October 17, 2010*

**college chemistry**

A volume of 0.285 L of a gas at STP weighs 0.537 g. Calculate the molar mass of the gas (1)(0.285) = n(0.0821)(273). .0036 is this correct?

*October 17, 2010*

**English**

make 2 words, first one 8 letters and second work 4 letters out of these s l r t n r u p a e s a

*October 17, 2010*

**english**

I'm doing an analysis on a class text and a self chosen related text and one of the things the sheet says to do is to identify and define the context of my related text. What does this mean?

*October 17, 2010*

**Sociology**

How does studying social institutions help sociologists understand society?

*October 13, 2010*

**Math-Calculus**

If f(x)=5ex+4xe find f'(x) .

*October 11, 2010*

**Help! Physics!!**

Water flows (v = approx 0) over a dam at the rate of 660 kg/s and falls vertically 86 m before striking the turbine blades. Calculate the rate at which mechanical energy is transferred to the turbine blades, assuming 53% efficiency. Express your answer using two significant ...

*October 7, 2010*

**Help! Physics!!**

A 120-kg crate, starting from rest, is pulled across a floor with a constant horizontal force of 400 N. For the first 17 m the floor is frictionless, and for the next 17 m the coefficient of friction is 0.34. What is the final speed of the crate? Express your answer using two ...

*October 7, 2010*

**college physics**

they have the same speed as each other at the instant they hit the ground. Trick question!

*October 5, 2010*

**Algebra**

Write 9850 in scientific notation

*October 3, 2010*

**AP English Literature**

I really like that as a thesis statement. Thank you so much! (:

*October 3, 2010*

**AP English Literature**

No...? I don't think so. I just want to make a point about how it's wrong to take the rights of a newborn baby because their parents sacrificed themselves to cross the border, and have their child be born in America, so it's easier for their child to have a '...

*October 3, 2010*

**AP English Literature**

I looked over it, but for some reason it didn't really help me.

*October 3, 2010*

**AP English Literature**

The thesis can only be in one place, which is the ending of the introduction. My thesis: "Everyone is entitled to their own opinion on how this problem should end, but it must be resolved." This "Illegal immigrants are now having "anchor babies" in the...

*October 3, 2010*

**AP English Literature**

Well so far I have my intro. which is this: Throughout the years, it has been known that if one's newborn is born in America, they have automatic citizenship, regardless of what their parent's situation may be; which is what the 14th Amendment states. Illegal ...

*October 3, 2010*

**AP English Literature**

I basically want to solve this problem and I want to talk about people's reaction, pros & cons, etc.

*October 3, 2010*

**AP English Literature**

I'm doing a research essay about "anchor babies", or in other words, babies born from illegal immigrants. How would you write a good thesis?

*October 3, 2010*

**Physics**

An airplane flies at 200.0 km/h relative to the air. What is the velocity of the plane relative to the ground if it flies during the following wind conditions? a. a 50.0-km/h tailwind b. a 50.0-km/h headwind.

*October 3, 2010*

**Physical chemistry**

Estimate the vapor pressure of sea water at 20C given that the vapor pressure of pure water is 2.338 kPa at that temperature and the solute is largely Na+ and Cl- ions, each present in about .50 mol/dm^3. I'm pretty sure the formula to use is pj=xjpj'. Where pj' is...

*September 30, 2010*

**Medical Terminology**

Treatment that's designed to reduce the intensity of painful symptoms but that doesn't produce a cure is

*September 28, 2010*

**Physics**

So in solving the answer it would be F=(8.99E9)*(2.5E13*1.6E-19)*(2.5E13*1.6E-19)/.50^2? If so, I don't think I did it right. I ended up with an answer of .57536

*September 26, 2010*

**Physics**

Two very small spheres are initially neutral and separated by a distance of 0.50 m. Suppose that 2.50 x 10^13 electrons are removed from one sphere and placed on the other. What is the magnitude of the electrostatic force that acts on each sphere?

*September 26, 2010*

**Mastering Chemistry**

Molarity(M)=amount (mol) of solute/volume (L)of solution. im gonna guess you have 11.0g and 75.0 mL convert ml to L -> 75/1000=0.075L ->177 molar mass of Luminol 11.0 x(1/177)/0.075 = your answer in units of M

*September 25, 2010*

**Calculus**

If h(t) represents the height of an object above ground level at time t and h(t) is given by h(t) = −16t2 + 96t + 1, find the height of the object at the time when the velocity is zero.

*September 22, 2010*

**geometry**

If m<PQR=(10x-7),m<RQT=5x, and m<PQT=(4x=6)

*September 20, 2010*

**Chemistry**

What is the molecular, ionic and net ionic formula for Acetic acid and sodium nitrate Molecular: Ionic: Net Ionic:

*September 20, 2010*

**physics**

When it says magnitude of velocity is that the same as the final velocity before impact? The word "magnitude" threw me off.

*September 19, 2010*

**physics**

A child throws a ball with an initial speed of 8 m/s at an angle of 40 degrees above the horizontal. The ball leaves her hand 1 m above the ground. How long is the ball in flight before it hits the ground? What is the magnitude of the ball's velocity just before it hits ...

*September 19, 2010*

**physics**

Richard is driving home to visit his parents125 mi of the trip are on the interstate highway where the speed limit is 65 mph Normally Richard drives at the speed limit, but today he is running late and decides to take his chances by driving at 80 mph.how many minutes will he ...

*September 19, 2010*

**Chemistry**

A mixture contains only NaCl and Al2(SO4)3. A 1.45-g sample of the mixture is dissolved in water and an excess of NaOH is added, producing a precipitate of Al(OH)3. The precipitate is filtered, dried, and weighed. The mass of the precipitate is 0.107 g. What is the mass ...

*September 18, 2010*

**physics**

Mary needs to row her boat across a 120 m -wide river that is flowing to the east at a speed of 1.4 m/s. Mary can row the boat with a speed of 2.0 m relative to the water. 1. How long does it take Mary to reach the opposite river bank ? 2.If Mary rows straight north, how far ...

*September 15, 2010*

**Chemistry**

How many moles of H2 can be produced from 7.74g SrH2? equation:SrH2 + 2H2O = Sr(OH)2 + 2H2

*September 14, 2010*

**Physical chemistry**

Calculate the pressure exerted by 1.0 mol C2H6 behaving as a perfect gas

*September 13, 2010*

**Calculus**

If h(t) represents the height of an object above ground level at time t and h(t) is given by h(t)=-16t2+11t+1 find the height of the object at the time when the speed is zero.

*September 13, 2010*

**Calculus**

ignore the "d=". Sorry!

*September 13, 2010*

**Calculus**

Let F(s)=5s2+5s+4 . Find a value of d greater than 0 such that the average rate of change of F(s) from 0 to d equals the instantaneous rate of change of F(s) at s=1. d=

*September 13, 2010*

**Chemistry**

I am really having trouble answering this question, can someone help? A binary compound between an unknown element E and hydrogen contains 91.27% E and 8.73% H by mass. If the formula of the compound is E3H8, calculate the atomic mass of E.

*September 12, 2010*

**Chemistry**

Fungal laccase, a blue protein found in wood-rotting fungi, is 0.390% Cu by mass. If a fungal laccase molecule contains four copper atoms, what is the molar mass of fungal laccase?

*September 11, 2010*

**Chemistry**

Consider equation 3A+B=C+D. You react 4 moles of A with 2 moles of B. Which of the following is true? 1) Limiting reactant (L.R.) is one with higher molar mass 2) A is L.R. because you need 6 moles of A and have only 4 moles 3) B is L.R. because you have fewer moles of B than ...

*September 11, 2010*

**ELAC**

Consider equation 3A+B=C+D. You react 4 moles of A with 2 moles of B. Which of the following is true? 1) L.R. is one with higher molar mass 2) A is L.R. because you need 6 moles of A and have only 4 moles 3) B is L.R. because you have fewer moles of B than A 4) B is L.R. ...

*September 11, 2010*

**9th grade math**

x to the 2nd power if x = 3/4 how do you find 3/4th to the 2nd power? 3/4th times 3/4th right? so the answer would be 9/16ths.. right?

*September 9, 2010*

**math**

You drove 2695 miles in 35 hours. (1) What is your average rate of change? (2) Suppose you can drive that distance at a legal 75 mile per hour rate. How long should it take you to complete the trip? (3) Suppose you are driving that distance at an illegal 86.8 miles per hour ...

*September 7, 2010*

**College Mathematics**

You drove 2695 miles in 35 hours. (1) What is your average rate of change? (2) Suppose you can drive that distance at a legal 75 mile per hour rate. How long should it take you to complete the trip? (3) Suppose you are driving that distance at an illegal 86.8 miles per hour ...

*September 7, 2010*

**english**

In the sentence: Hello, my name is Melissa. What is the predicate?

*September 1, 2010*

**algebra**

a student writes 5y.3 to model the relationship the sum of 5y and 3.explain the error

*August 29, 2010*

**The elements and Principles of Design**

9-D just took the test

*August 19, 2010*

**Math**

How do you do a division problem?

*August 16, 2010*

**pre-algebra**

2/x-5=1/x+2 the teacher said i got it wrong when i got -1/7 he got -9 if that is please explain.

*August 2, 2010*

**accoutning**

what is an advantage of the partnership form of business organization is? 1. unlimited liability 2. mutual agency 3. ease of formation 4. limited life

*July 30, 2010*

**Math-Stats**

The Acme Candy Company claims that 60% of the jawbreakers it produces weigh more than .4 ounces. Suppose that 800 jawbreakers are selected at random from the production lines. Would it be unusual for this sample of 800 to contain 418 jawbreakers that weigh more than .4 ounces?

*July 28, 2010*

**geometry**

you are building a ramp that will be in the shape of a perfect right-angled triangle. The vertical height of th ramp will be 10 feet. the horizontal base of the ramp will be 15 feet. what will be the length of the downward sloping side of the ramp?

*July 8, 2010*

**Chemistry**

Write the chemical formulas for the compounds containing each of the following: a) one calcium atom for every two iodide atoms. b) two nitrogen atoms for every four oxygen atoms. c) one silicon atom for every two oxygen atoms. d) one zinc atom for every two chlorine atoms

*July 1, 2010*

**Chemistry**

Write the chemical formulas for the compounds containing each of the following: a) one calcium atom for every two iodide atoms. b) two nitrogen atoms for every four oxygen atoms. c) one silicon atom for every two oxygen atoms. d) one zinc atom for every two chlorine atoms

*July 1, 2010*

**Statistics**

Using the major League Baseball Data set available through the "Data Sets" lin in the materials section, answer the research question of whether the number of wins of a team can be explained linearly by the size of stadium, ERA, and stolen bases. Prepare a 750-1,050 ...

*June 30, 2010*

**algebra**

1800 kilometers ?

*June 22, 2010*

**algebra**

A stack of $10 bills is worth $90 billion dollars. What is the height of the stack in kilometers? Assume each bill is .2 millimeters high.

*June 22, 2010*

**math**

how long will it take for $7600 to double if invested at 4.2%,componded continously

*June 18, 2010*

**business**

Ziggy’s Famous Yogurt blends regular yogurt that is 3% fat with its no-fat yogurt to obtain lowfat yogurt that is 1% fat. How many pounds of regular yogurt and how many pounds of no-fat yogurt should be mixed to obtain 60 pounds of low-fat yogurt

*June 15, 2010*

**business**

Donna invested her $33,000 bonus and received a total of $970 in interest after one year. If part of the money returned 4% and the remainder 2.25%, then how much did she invest at each rate

*June 15, 2010*

**Science**

If neons atomic number is 10 how many electrons are in the outer energy level?

*June 10, 2010*

**math**

An actuary at an insurance company estimates from exsiting data that on a $1000 policy an average 1 and 100 policyholders will file a 20000 claim. in average of 1 in 200 policyolders will file a 50000 claim in average 1 in 500 policyholders will file a 100000 claim. a. what is...

*May 22, 2010*

**statistical reasioning**

An actuary at an insurance company estimates from exsiting data that on a $1000 policy an average 1 and 100 policyholders will file a 20000 claim. in average of 1 in 200 policyolders will file a 50000 claim in average 1 in 500 policyholders will file a 100000 claim. a. what is...

*May 21, 2010*

**technolgy and society**

one skill that's generally expected of technology workers is

*May 16, 2010*

**Geography**

What geographic features might create differences in France's and Germany's economies?

*May 13, 2010*

**Math**

A pan of cold water with a temeprature of 35 degrees F is brought into a room with a temperature of 75 degrees F. After one hour, the temperature in the pan is 45 degrees F. a) Write a formula for the temperature (T) as a function of time (according to Newton's Law of ...

*May 12, 2010*

**geography**

Germany and France are located next to eachother. What geographic advantages do they have in common that would help their economies prosper? what geographic features might create differences in their economies?

*May 10, 2010*

**chem**

Use this percentage to calculate the mass of fluorine in grams contained in 29.0 g of copper (II) fluoride

*April 25, 2010*

**english**

using these words : animate, dogged, gravity,indomitable,retaliate 1.This is what people do by dettling a score, getting even, and given other people a dose of their own medicine. which word describes this

*April 15, 2010*

**organic chemistry**

if sodium iodoacetate is used instead of sodium chloroacetate, how will the rate of reaction be affected? explain.

*April 14, 2010*

**Mathematic**

v-8<35

*April 13, 2010*

**3rd grade**

one dividend in my fact family is 18 one of my divisors is twice one of myquotients what three numbers are in my fact family

*April 1, 2010*

**Organic Chemistry**

When 2-methyl-2-butene is bubbled into dilute sulfuric acid at room temperature, it appears to dissolve. what new substance has been formed?

*March 30, 2010*

**Chemistry**

Calculate the electrical voltage of an electrochemical cell using Pb(s) and Co(s) as electrodes along with their appropriate solutions. Co2+(aq) + 2e- --> Co(s) -0.28 V Pb2+(aq) + 2e- --> Pb(s) -0.13 V The oxidation reaction is Co(s) --> Co2+(aq) + 2e- +0.28V E0 net(...

*March 18, 2010*

**Chemistry**

What does it mean to have a percent yield over 100?

*March 5, 2010*

**Psychology 202**

Neurologists involved in animal research studies of cognitive function see analogies in humans that suggest mental exercise reduces loss of brain mass. Which of the following statements describe their findings? (Points :1) Older adults who continue complex mental activities ...

*March 4, 2010*