Monday

December 22, 2014

December 22, 2014

Total # Posts: 1,716

**Chemistry**

Calucluate the pH of 100 mL of buffer that is 0.075 M NH4Cl and 0.175 M NH3 before and after the addition of 1.00 mL of 5.05 M HNO3 I have no idea where to even start. HELP!
*February 20, 2012*

**physics**

With brakes fully applied, a 1660 kg car decelerates from a speed of 74.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car?
*February 20, 2012*

**physics**

A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...
*February 20, 2012*

**physics**

thank you
*February 18, 2012*

**physics**

A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...
*February 18, 2012*

**chemistry**

At 25 °C, the equilibrium partial pressures for the following reaction were found to be PA = 6.30 atm, PB = 7.20 atm, PC = 6.40 atm, and PD = 9.10 atm. 2A(g) + 2B(g)-->C(g) + 3D(g) What is the standard change in Gibbs free energy of this reaction at 25 °C.
*February 17, 2012*

**physics**

With brakes fully applied, a 1660 kg car decelerates from a speed of 74.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car?
*February 17, 2012*

**physics**

A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...
*February 17, 2012*

**Chemistry**

A flask containing a gas was connected to both a closed-end and an open-end manometer. In the closed-end manometer, the mercury in the sealed arm was 755 mm above the level in the arm connected to the fax. In the open-end manometer,the arm connected to the gas was 17 mm higher...
*February 16, 2012*

**chemistry**

A flask containing a gas was connected to both a closed-end and an open-end manometer. In the closed-end manometer, the mercury in the sealed arm was 755 mm above the level in the arm connected to the fax. In the open-end manometer,the arm connected to the gas was 17 mm higher...
*February 16, 2012*

**chemistry**

Write the balanced chemical equation for each of these reactions. Include phases. However, when additional aqueous hydroxide is added the precipitate redissolves forming a soluble [Pb(OH)4]2–(aq) complex ion.
*February 13, 2012*

**chemistry**

Which of the following will be more soluble in an acidic solution than in pure water? AgBr Be(OH)2 RbClO4 CaCO3 PbSO4
*February 13, 2012*

**chemistry**

Silver chromate is sparingly soluble in aqueous solutions. The Ksp of Ag2CrO4 is 1.12× 10–12. What is the solubility (in mol/L) of silver chromate in 1.00 M potassium chromate aqueous solution?
*February 13, 2012*

**chemistry**

At a certain temperature, the solubility of strontium arsenate, Sr3(AsO4)2, is 0.0510 g/L. What is the Ksp of this salt at this temperature?
*February 13, 2012*

**chemistry**

At 25 °C only 0.0580 mol of the generic salt AB3 is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?
*February 13, 2012*

**chemistry**

A generic salt, AB2, has a molar mass of 159 g/mol and a solubility of 3.30 g/L at 25 °C. What is the Ksp of this salt at 25 °C?
*February 13, 2012*

**chemistry**

Write the balanced chemical equation for each of these reactions. Include phases. When aqueous sodium hydroxide is added to a solution containing lead(II) nitrate, a solid precipitate forms. However, when additional aqueous hydroxide is added the precipitate redissolves ...
*February 13, 2012*

**chemistry**

Copper(I) ions in aqueous solution react with NH3(aq) according to Cu+(aq) + 2NH3(aq) -->Cu(NH3)2^+ Kf = 6.3x10^10 Calculate the solubility (in g·L–1) of CuBr(s) (Ksp = 6.3× 10–9) in 0.41 M NH3(aq).
*February 13, 2012*

**chemistry**

thank you
*February 13, 2012*

**chemistry**

I posted a few questions and they all disappeared so i reposted.
*February 13, 2012*

**chemistry**

At 25 °C only 0.0990 mol of the generic salt AB is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?
*February 13, 2012*

**Chemistry**

What additional information would be needed to calculate the rate in units of concentration per time?
*February 9, 2012*

**math**

multiply 6sqrt25x^3*sqrt4x^3
*February 8, 2012*

**algebra**

multiply 6sqrt25x^3
*February 8, 2012*

**physics**

Two blocks with masses m1 = 20.7 kg and m2 = 55.5 kg, shown in the figure, are free to move. The coefficent of static friction between the blocks is 0.74 but the surface beneath m2 is frictionless. What is the minimum force F required to hold m1 against m2?
*February 8, 2012*

**Chemistry**

20.7mL of ethanol (density=0.789g/mL) initially at 8.2 degrees Celsius is mixed with 37.1 mL of water (density=1.0g/mL) initially at 25.7 degrees Celsius in an insulated beaker. Assuming that no heat is lost, what is the final temperature of the mixture? This is how I set up ...
*February 7, 2012*

**chemistry**

Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.
*February 5, 2012*

**chemistry**

A cook wants to heat 1.10kg of water from 33 C to 100 C. If he uses the combustion of natural gas which is exothermic to heat the water, how much natural gas will he need to burn? Natural gas produces 49.3 kJ/gram.
*February 4, 2012*

**chemistry**

Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.
*February 4, 2012*

**Physics**

A car that weighs 14600.0 N is initially moving at a speed of 58.0 km/hr when the brakes are applied and the car is brought to a stop in 4.7 s. Find the magnitude of the force that stops the car, assuming it is constant.
*February 3, 2012*

**math**

While riding your motorcycle, you break to miss hitting a dog. your tires leave a skid mark as you come to a stop. the skid mark forms four angles when it crosses the painted line on the side of the road. one angle formed a 62 degree angle. what other angles are formed?
*February 1, 2012*

**chemistry**

At 20 °C, chloroform (CHCl3) has a density of 1.489 g/mL. What is the mass of 7.52 mL of chloroform at 20°C?
*January 31, 2012*

**chemistry**

When 15.5 + 0.125 + 2.55 are added, the answer with the correct number of significant figures is
*January 31, 2012*

**ANATOMY**

the three major vessels of the portal triad are the hepatic artery, hepatic portal vein and bile duct. What is the location of the triad relative to the liver lobules?
*January 29, 2012*

**science**

Circle the term that does not belong in each of the following groupings. 1. HC1 secretion Acetyicholine Histamine Secretin Gastrin 2. Gastric emptying Slowed by fats Enterogastric reflex Solid foods 3. Cephalic phase Reflex phase Intestinal phase Psychological stimuli 4. ...
*January 29, 2012*

**Physics**

A ball is thrown horizontally from the roof of a building 29.7 m high at 39.6 m/s. (a) What is the vertical velocity of the ball when it lands? (use down as the positive y-axis direction)b) What is the ball’s total velocity (speed and direction) when it lands?
*January 23, 2012*

**physics**

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (as shown in the figure below). Suppose that you loft the ball with an initial speed of v = 15.6 m/s, at an...
*January 22, 2012*

**chemistry**

What is the pH of a 2.8 M solution of HClO4?
*January 22, 2012*

**chemistry**

What is the pH of a 2.8 M solution of HClO4?
*January 22, 2012*

**chemistry**

i didnt know ph could be greater than 14 and poh less than 0
*January 22, 2012*

**chemistry**

A solution of NaOH(aq) contains 6.2 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.
*January 22, 2012*

**chemistry**

A solution of NaOH(aq) contains 6.2 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.
*January 22, 2012*

**science/anatomy**

common pathways for food and air are the (1), which connects to the mouth, and (2), which connects to the larynx. Epithelium in this region is (3), which provideds good protection from friction. Three bands of skeletal muscle, the (4) propel food into the (5). Entrance to the ...
*January 19, 2012*

**ENGLISH**

I have to write an essay about whether or not Jonathan Swift's "A Modest Proposal" was effective as a satire. one quote i have is "I have been assured by a very knowing American of my acquaintance in London, that a young healthy child well nursed, is, at a ...
*January 17, 2012*

**science**

how is eating breakfast important to prevent fainting
*January 16, 2012*

**SCIENCE**

what are the physiological benefits of eating breakfast. what are the physiological occurances or causes of fainting (syncope). how are these two ^ related and what is the significance
*January 16, 2012*

**ANATOMY**

what are the physiological benefits of eating breakfast. what are the physiological occurances or causes of fainting (syncope). how are these two ^ related and what is the significance
*January 16, 2012*

**math**

yo mama
*January 8, 2012*

**Math**

Please check- I got 10 4(9-2)/2^2+3
*January 5, 2012*

**MATH**

Look at this inequality 4m-9<2m-3 Solve the inequality for m. PLEASE HELP ME! CAN YOU PLEASE DO IT STEP BY STEP?
*December 30, 2011*

**algebra**

haaaa
*December 15, 2011*

**Business Statistics**

Instructions: Prepare your answers using Excel and show your work to get full or partial credit. Question 1: Using the file Wages.xlsx which contains information of working individuals, for a nationwide firm (Value 7 points). a) Run Descriptive Statistics for the variables ...
*December 14, 2011*

**College English**

How can I compare "Mother Night" by Vonnegut and "Song of Solomon" by Morrison in terms of Postmodernism?
*December 11, 2011*

**Statistics**

A shipment of portable radios contains 14 good radios and 3 defective ones. If two are randomly selected (without replacement) and tested, find the probability that at least one will be defective.
*December 10, 2011*

**Statistics**

A shipment of portable radios contains 14 good radios and 3 defective ones. If two are randomly selected (without replacement) and tested, find the probability that at least one will be defective.
*December 10, 2011*

**calculus II**

Do a u substitution. u= 1- sqrt(x) du = -(1/(2*sqrt(x)))dx Change your limits by plugging them into the u equation. u= 1 - sqrt(0) = 1-0 = 1 u= 1 - sqrt(9/16) = 1-(3/4) = 1/4 Substitute the u values in for x. The new integral is -2*sqrt(u) du from [1,1/4] OR 2*sqrt(u) du from...
*December 10, 2011*

**------college algebra division**

Whoops, some of it didn't line up, but I used the long division method
*December 10, 2011*

**------college algebra division**

5x^2 -3x -18 +((12x+71)/(x^2+4)) ___________________________ x^2 +4| 5x^4 -3x^3 +2x^2 +0x -1 -5x^4 -20x^2 --------------------------- -3x^3 -18x^2 +0x -1 +3x^2 +12x --------------------- -18x^2+12x -1 +18x^2 +72 --------------- 12x +71
*December 10, 2011*

**statistics**

The claim: mean < 900 other option: mean > or = 900 The null hypothesis is the one with an equal sign... Your null hypothesis would be mean=900 Your alt. hypothesis would be mean<900 The alt. hypothesis is the claim.
*December 9, 2011*

**history**

Levy's purpose in the film Crimes and Misdemeanors
*December 8, 2011*

**Math**

On a grid, an upright square is a square that is well, upright, on one of its sides, with the sides going along the grid points.
*December 5, 2011*

**Math**

I need help on this question, I know the answer (or, at least I think I know it), but I can't think of the rest. Bobby claims that only upright squares can have rational numbers for side lengths. Is he correct? Explain. I got yes, he is correct, but I can't hink of an ...
*December 5, 2011*

**Science**

Well, you can write down what your phenotypes are (how you look, ex: eye color, hair color, hair type, etc.) and then by using that, you canfigure out your genotypes by researching whether each of your traits are dominant or recessive. For example, I have a straight hairline, ...
*December 5, 2011*

**Chemistry**

Suppose 33.5 g of ClF3(g) and 29.1 g of Li(s) are mixed and allowed to react at atmospheric pressure and 25 C until one of the reactants is used up, producing LiCl(s) and LiF(s). Using the NIST value for the enthalpy of formation of ClF3 (webbook.nist.gov), calculate the ...
*December 4, 2011*

**Chemistry**

A 2.3 g sample of C5H10O is burned completely in excess oxygen to yield CO2(g) and H2O(l) at 25 C, releasing 83.42 kJ of energy. What is the enthalpy of formation of C5H10O?
*December 4, 2011*

**chemistry**

Calculate the volume of natural gas (methane) required to bring 2.6 L of water to a boil. Assume the initial temperature of the water is 21 C, and the methane is at 1 bar and 25 C. Assume that methane is an ideal gas, the specific heat capacity of water to be constant and ...
*December 4, 2011*

**Thermochemistry**

Hint: Write the balanced combustion reaction. You can find the standard enthalpies of formation for O2, CO2, and H2O from many sources, including the CRC Handbook of Chemistry and Physics. Solution: Balanced combustion reaction: C8H18 + 12.5 O2 --> 8 CO2 + 9 H2O From the ...
*December 4, 2011*

**Physics**

Pam has a mass of 44.0 kg and she is at rest on smooth, level, frictionless ice. Pam straps on a rocket pack. The rocket supplies a constant force for 22.0 m and Pam acquires a speed of 58.0 m/s.
*December 1, 2011*

**Science 7R (Lab questions) **

Animal cells lack in a cell wall. Plant cells have it.
*December 1, 2011*

**trig**

pi/3 is 7 square root 3/ 2 pi is - 7 square root 3 / 2 and 7pi/6 is -7
*November 29, 2011*

**trig**

i didn't realize it was just plugging in! thanks! i just need to figure out how to subtract fractions with pi in them now
*November 29, 2011*

**trig**

For the following expression, find the value of y that corresponds to each value of x, then write your results as ordered pairs (x,y). y=7cos(x-pi/6) for x=pi/6, pi/3, 2pi/3, pi, 7pi/6
*November 29, 2011*

**chemistry**

Which of the following sets of solute and solvents will make a homogeneous solution? (naphthalene is a non-polar organic molecule) 1. Water and benzene 2. Benzene and ammonium nitrate 3. Benzene and naphthalene 4. Water and naphthalene
*November 29, 2011*

**chemistry**

What is the molecular geometry for SH2? 1. Bent 2. Trigonal planar 3. Tetrahedral 4. Liner
*November 29, 2011*

**chemistry**

What volume of a 7.00 M solution of Ca(OH)2 is needed to neutralize 37.2 mL of a 3 M solution of nitric acid? 1. 15.9 mL 2. 37.2 mL 3. 7.97 mL 4. 24.2 mL
*November 29, 2011*

**chemistry**

What is the mass percent of a solution if 42.9 grams of aspirin is dissolved into 175 mL of ethanol? (Density of ethanol is 0.789 g/mL) 1. 31.1 % 2. 24.5 % 3. 23.7 % 4. 19.7 %
*November 29, 2011*

**chemistry**

How many moles of NaOH are in 23.5 mL of a 1.50 M solution? 1. 0.0353 moles 2. 35.26 moles 3. 16.7 moles 4. 0.0235 moles
*November 29, 2011*

**chemistry**

What is the mass percent of a solution if 42.9 grams of aspirin is dissolved into 175 mL of ethanol? (Density of ethanol is 0.789 g/mL
*November 29, 2011*

**calculus**

Let f''(x)=5x+5 with f'(2)=1 and f(-2)=2. Find f'(x) and f(3)?
*November 28, 2011*

**calculus**

Consider the function whose second derivative is f''(x)=7x+6sin(x). If f(0)=2 and f'(0)=3 , find f(x) .
*November 28, 2011*

**MATH HELP! **

if f(x)+(x-3)^4(2x-1)^3, find the value(s) of x which solve f'(x)=0
*November 28, 2011*

**Physics**

A great white shark with a mass of 3000 kg swimming at 3.00 m/s swallows a 250 kg fish at rest. What is the speed of the great white shark right after swallowing the fish?
*November 28, 2011*

**MATH**

if f(x)=(x-3)^4(2x+1)^3 find the value(s) of x which solve f'(x)=0
*November 27, 2011*

**MATH**

Complete the indefinite integral: ∫(x^2+1)^2 dx
*November 26, 2011*

**SCIENCE**

the brachialis is a short stout muscle inserting cloes to the fulcrum of the elbow joint' the brachioradialis is a slender muscle inserting distally, well way from the fulcrum of the elbow joint. Which is a mechanical advantage and which is a disadvantage
*November 22, 2011*

**anatomy**

In the body, lever systems involve the interaction of __1__, which provide the force, and __2__, which provide the lever arms. The force is exerted where __3__. The site at which movement occurs in each case is the intervening __4__, which acts as a fulcrum. 1. muscles? 2. ...
*November 22, 2011*

**ANATOMY**

place the following in order (1-11): Myosin heads bind to active sites on actin molecules ATP is hydrolyzed Myosin heads return to their high-energy shape(******), ready for the next working stroke Calcium ions bind to troponin Cycling continues until calcium ions are ...
*November 15, 2011*

**MATH**

Find the value of A + B if the A is the first term and B is the common difference of the sequence whose 4th term is 3 and 20th term is 35
*November 7, 2011*

**MATH HELP! **

find all possible values of the common ratio of the geometric sequence a, b, 6, ... if a+b=1
*November 7, 2011*

**Physics**

A wire is frictionless between points A and B and rough between B and C. A is 5m above the ground, B is zero, and C is 2m above the ground. The 0.400kg bead starts from rest at A. If the bead comes to rest at C, find the loss in mechanical energy as it goes from B to C. I can...
*November 6, 2011*

**Physics**

An Alaskan rescue plane traveling 36 m/s drops a package of emergency rations from a height of 137 m to a stranded party of explorers.Where does the package strike the ground relative to the point directly below where it was released
*November 3, 2011*

**MATH**

given the arithmetic sequence 71,65,59 ... if a(n) is -43 what is the value of n
*October 31, 2011*

**MATH**

a pile of bricks has 85 bricks in the bottom row, 79 bricks in the second row, 73 in the third row, and so on until there is only 1 brick in the top row. how many bricks are in the 12th row? how many rows are there in all?
*October 31, 2011*

**chemistry**

If 58g of NaOH are dissolved in water to make a final volume of exactly 400mL, what is the molar concentration of NaOH? (The FM of NaOH = 40.0) How do I set this up?
*October 31, 2011*

**algebra**

i need help with my math for college, im currently a little behind, ive had 2 tutors but the tutors that ive had dont really know what there doing, this is stressful and im hopig someone who knows what there doing can help me
*October 30, 2011*

**HELP**

subtract simplify by removing factor of 1 if possible 3bc/b^2-c^2-b-c/b+C
*October 28, 2011*

**Help**

Solve the equation q+7/4+q-3/3=5/2 I think there is no solution
*October 28, 2011*

**Help**

Divide and simplify x^2-16/x divide by x+4/x+1 I get (x-4)(x+1)/X is this correct
*October 28, 2011*

**Help**

simplify by removing factor of 1 7z-49/7z I have the answer as -7
*October 28, 2011*

**Help**

Find the LCM t^3+8t^2+16,t^2-8t
*October 28, 2011*

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