# Jin

Popular questions and responses by Jin-
## chemistry

Predict whether the following solutions are acidic, basic, or nearly neutral: a. NaBr, b. K2SO3, c. NH4NO2, d. Cr(NO3). the answer is neutral, basic, acidic, acidic and i am not sure why

*asked on July 4, 2010* -
## chemistry

How do you know if these solutions are acidic, basic, or nearly neutral? a. NH4NO2 b. Cr(NO3)3

*asked on July 24, 2010* -
## chemistry

how do you solve this problem?? What is the original molarity of a solution of formic acid (HCOOH) whose pH is 3.26 at equilibrium? the answer is 2.3 x 10^-3M.

*asked on July 4, 2010* -
## math

If a ball is thrown straight up into the air with an initial velocity of 95 ft/s, it height in feet after t second is given by y=95t–16t2. Find the average velocity for the time period begining when t=1 and lasting (i) 01 seconds: (ii) 001 seconds: (iii)

*asked on August 11, 2010* -
## physics

In Figure (a), a block of mass m lies on a horizontal frictionless surface and is attached to one end of a horizontal spring (spring constant k) whose other end is fixed. The block is initially at rest at the position where the spring is unstretched (x =

*asked on October 24, 2009* -
## chemistry

lithium + gold(III) chloride +lithium chloride + gold need to balance equation

*asked on December 5, 2010* -
## math

An open box is to be made from a flat piece of material 18 inches long and 2 inches wide by cutting equal squares of length xfrom 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

*asked on August 11, 2010* -
## chemistry

Write balanced equations and solubility product expressions for the solubility equlibria of the following compounds: a. CuBr b. ZnC2O4 c. Ag2CrO4 d. Hg2Cl2 e. AuCl3 f. Mn3(po4)2 can you give me some examples using the compounds given?

*asked on July 19, 2010* -
## PHYSICS

Wile E. Coyote is holding a “HEAVY DUTY ACME ANVIL” on a cliff that is 40.0 meters high. The Roadrunner (beep-beep), who is 1.0 meter tall, is running on a road toward the cliff at a constant velocity of 10.0 m/s. Wile E. Coyote wants to drop the anvil

*asked on November 9, 2009* -
## Algebra

For 1980 through 1990, the average weekly earnings (in dollars)for workers in the United States can be modeled by E= 14.5t + 270, where t is the number of years since 1980. Approximate the average weekly earnings in 1980 and 1990. I am having trouble

*asked on August 25, 2005* -
## Math

How many toothpicks are needed for nth design? Explain how do you figure out.

*asked on May 18, 2018* -
## chemistry

A salt that could decrease the ionization of HCOl in soln is probably a. NaOH b. NaCl c. NaOCl d. NaH e. none of these how would you solve this

*asked on July 27, 2010* -
## chemistry

To have a color, the transition metal complex should have an electron in a d-orbital, and an unoccupied spot in a higher energy d-orbital. • Practice Problem. • Predict whether each of the following complexes could be colored: (a) [Sc(H2O)6]3+ (b)

*asked on July 27, 2010* -
## chemistry

Determine the oxidation state of each transition metal in the following cmpds. (a) Na2MoO4 (b) KAuCl4 (c) MgWO4 and (d) Ni(CO)4

*asked on July 27, 2010* -
## chemistry

how do you solve this? The candy indistry converts sucrose (C11H22O11,table sugar),a crystalline material, to invert sugar, a hydrolzyed [rpdict tjat os 50:50 frutose and glucose. The hydrolysis occurs in water, quite slowly, at an elevated temperature of

*asked on July 27, 2010* -
## chemistry

I had this on a test, not sure how to do it Explain, using balanced chemical reactions with the smallest integer coefficients, why each of following occurs. a. CuI2 (insoluble in pure water) dissolves readily in aqueous ammonia, HN3(aq) b. AgBr (insoluble

*asked on July 24, 2010* -
## chemistry

Explain, with balanced ionic equations, why a. CuI2 dissolves in ammonia solution b. AgBr dissolves in NaCN solution, c. HgCl2 dissolves in KCL solution.

*asked on July 19, 2010* -
## Math

How many toothpicks are needed for nth design? Explain how do you figure out.

*asked on May 18, 2018* -
## Statistic

According to the CDC, 25 % of college students get the flu every year. (a) If 7 college students are selected at random? What is the probability that exactly 6 of them have the flu? (b) What is the mean and standard deviation for this distribution?

*asked on November 28, 2015* -
## Physics

An orange rolls across a table with a speed of 0.5 m/s and falls off the edge. If it lands 3 m from the edge of the table, from what height does it fall?

*asked on March 6, 2015* -
## algebra

A ball is thrown into the air with an upward velocity of 28 ft/s. Its height (h) in feet after t seconds is given by the function h = –16t² + 28t + 7. How long does it take the ball to reach its maximum height? What is the ball’s maximum height? How

*asked on March 26, 2012* -
## Calculus

find all values of x for which function is differentiable. y=lnx^2 why is the answer= for all x doesn't equal 0?

*asked on October 29, 2010* -
## Calculus

find the derivative y= csc^-1 (secx) 0 less than or equal to x less than or equal to 2¤Ð what did i do wrong? - 1/ secx sqrt(secx^2 -1) * secxtanx

*asked on October 29, 2010* -
## 9 th science

distinguish between tolerance range and optimal range

*asked on September 13, 2010* -
## calculus

find the domain of function f(x)= (5x + 4)/(x^2 + 3x + 2) is the answer.. x can't be -2 or -1?

*asked on August 4, 2010* -
## chemistry

Faraday¡¯s Law of Electrolysis • Practice Problem. • What is the oxidation state of the osmium atom in an unknown salt if 26.7 grams of osmium plate out when a current of 15 amps is passed through a solution of this salt for 1 hour?

*asked on July 27, 2010* -
## chemistry

The values of Ksp for AgBr and AgCl, are 7.7x10^-13 and 1.6 x 10^-10. A solution containing a mixture of 2.0x10^-2 M Br and 2.0 x 10^-2M Cl is a candidate for separating using selective precipitation. Solid AgNO3 is added, with a miniature spatula, and

*asked on July 24, 2010* -
## chemistry

How do you solve this problem? In a certain industrial process involving a heterogeneous catalyst, the volume of the catalyst (in the shape of a shpere) is 10.0cm^3. Calculate the surface area of the catalyst. IF the sphere is broken down into eight

*asked on July 15, 2010* -
## chemistry

how do you solve this problem? consider the reaction A->B the rate of the reaction is 1.6 x 10^-2 M/s when the concentration of A is 0.35 M. Calculate the rate constant if the reaction is a) first order in A and b) second order in A.

*asked on July 15, 2010* -
## chemistry

Find the mass of liquid water required to absorb 4.81×104 kJ of heat energy on boiling. Answer in units of g.

*asked on March 17, 2020* -
## physics

A girl with a 69.2 g yo-yo is swinging it in a horizontal circle at an angular velocity of 6.55 rad/s. If the string is tilted down at an angle of 20.4°, what must the length of the yo-yo string be?

*asked on October 25, 2019* -
## Geography

Sailing west from England on which continent would you first make landfall?

*asked on October 20, 2018* -
## Math

Tickets to the school play cost $4 for adults and $2 for students. If 255 adults and 382 students attended the play, write an expression that shows the total amount of money made on ticket sales. Then evaluate the expression.

*asked on October 1, 2018* -
## English

Is "words are eaten" personification?

*asked on November 11, 2017* -
## Math

Two tourists went on a hike at dawn. One went from a to b and another one went from b to a. They met at noon but did not stop and continued walking maintaining same speed for the whole trip. One finished his hike at 4pm in B and another one came to A at 9

*asked on October 30, 2017* -
## Calculus MATH

Problem statement a) Suppose f(x) is defined on 0 ≤ x ≤ 1 by the following rule: f(x) is the first digit in the decimal expansion for x. For example, f(1/2) = 5 and f(0.719) = 7. Sketch the graph of y = f(x) on the unit interval with appropriate scales

*asked on November 30, 2016* -
## Economics

Suppose that 20 workers were required in 2010 to produce 120,000 bushels of wheat on a 1,000-acre farm. a. What is the average output per acre? (?) bushels per acre What is the average output per worker? (?) bushels per worker b. If in 2020 only 16 workers

*asked on August 20, 2015* -
## math

Draw a picture that represents 3x50=150?

*asked on March 17, 2015* -
## chemistry

I'm working on substitution organic chemistry problems and I just had a question. There's an equation in which a molecule is treated with methanol in an acetone solution. Would the reaction be SN1 or SN2? I thought that it was SN2 because of the aprotic

*asked on November 29, 2014* -
## chemistry

The activation energy, Ea, for a zeroth-order reaction, X-->products, is most readily obtained from the slope of a plot of: (choose from below) -[X] vs time -ln k vs time -rate vs time -[X]^2 vs time -ln[X] vs time -1/[X] vs time -ln k vs 1/T, where T is

*asked on June 18, 2014* -
## chemistry

A reaction has a first order rate constant of (6.25x10^-5 1/s) at T=298.15K and (0.0000538 1/s) at T=338.15K. What is the value of the rate constant at T=316.15K?

*asked on June 18, 2014* -
## chemistry

According to the mechanism below, what is the correct expression for the rate consumption of A? In the mechanism, M is a molecule that collides with A and A* is a highly-energized for of A. Step 1: A+M A*+M : rate constants k1 and k-1 Step 2: A* C : rate

*asked on June 18, 2014* -
## chemistry

The decomposition reaction, x-->products, is second-order with rate constant k=0.0183 L/(s)(mol). How long will it take for the decomposition to be 95% complete, if the intitial concentration of X is 1.25mol/L? Thanks

*asked on June 18, 2014* -
## chemistry

if a college student went into the lab and produced 45 grams of Na2CO3, what is percent yield of this trial?

*asked on February 25, 2014* -
## chemistry

LAST QUESTION: When solid NH4NO3 decomposes, a mixture of gases is obtained: 2 NH4NO3(s)--> 4H2O(g) + O2(g) + 2 N2(g) In an experiment, 5.02 g NH4NO3 decomposes completely in a rigid 5.00-L container. What is the total pressure in the container if the

*asked on February 24, 2014* -
## chemistry

It takes 19.6 mins for a 10.0mL sample of an unknown gas to effuse through a pinhole. A 10.0mL sample of He, required 5.05mins. What is the molar mass of the unknown gas? I got that you have to do : effuse rate of He/Effuse rate of Mx = Square root of

*asked on February 24, 2014* -
## chemistry

Carbon monoxide, CO and hydrogen, H2, react accordingly: 4CO(g)+9H2(g)-->C4H10(g)+4H2O What volume of the EXCESS REACTANT remains if 17.2L CO and 42.1L H2 are allowed to react? Assume both gases are measured at 711 degree celsius and 1.33atm.

*asked on February 24, 2014* -
## chemistry

What is the density of CH4 gas at 32.7 degree celsius and 109kPa? The molar mass of CH4 is 16.042g/mol.

*asked on February 24, 2014* -
## History

Describe and evaluate President Eisenhower’s policy regarding Joseph McCarthy.

*asked on January 8, 2012* -
## calculus

f(x)=8x^3+1x^2–8x+2/–7x^2–4x+9 Find the equation of the non-vertical asymptote. y = Does f(x) intersect its non-vertical asymptote? (yes or no) What is the smallest value of x at which f(x) intersects its non-vertical asymptote? ( Enter No in the

*asked on September 4, 2010* -
## calculus

Consider the function f(x)=–3x3–1x2+1x+1Find the average slope of this function on the interval (–2–1). By the Mean Value Theorem, we know there exists a c in the open interval (–2–1) such that f(c) is equal to this mean slope. Find the value

*asked on September 4, 2010* -
## calculus

se differential, i.e., linear approximation, to approximate (8.4)^(1/3) as follows: Let f(x)=(x )^(1/3). The linear approximation to f(x) at x=8 can be written in the form y=mx+b where m is: and where b is: Using this, we find our approximation for

*asked on August 28, 2010* -
## calculus

The circumference of a sphere was measured to be 78.000 cm with a possible error of 0.50000 cm. Use linear approximation to estimate the maximum error in the calculated surface area. Estimate the relative error in the calculated surface area.

*asked on August 28, 2010* -
## calculus

A street light is at the top of a 16 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 4 ft/sec along a straight path. How fast is the tip of her shadow moving when she is 40 ft from the base of the pole?

*asked on August 28, 2010* -
## math

The horizontal asymptotes of the curve y=12x/(x4+1)^(1/4)

*asked on August 28, 2010* -
## math

he circumference of a sphere was measured to be 78000 cm with a possible error of 050000 cm. Use linear approximation to estimate the maximum error in the calculated surface area.

*asked on August 27, 2010* -
## math

A spherical snowball is melting in such a way that its diameter is decreasing at rate of 0.2 cm/min. At what rate is the volume of the snowball decreasing when the diameter is 12 cm. (Note the answer is a positive number).

*asked on August 27, 2010* -
## math

How do you find the derivative of square root of five /t^5? how do you find the derivative of square root of five /t^5 I know that f=a t^-n f'= -an t^(-n-1) and i tried putting -25/{[2sqrt(5/t^5)]/(t^4)}

*asked on August 20, 2010* -
## math

what is the derivative of f(x)=6sin2x I put 12cosx...

*asked on August 20, 2010* -
## math

If a ball is thrown vertically upward from the roof of 32 foot building with a velocity of 80 ft/sec, its height after t seconds is s(t)=32+80t–16t2. What is the maximum height the ball reaches? What is the velocity of the ball when it hits the ground

*asked on August 20, 2010* -
## math

If f(x)=(x^2+3x+4)^2 how do you find the derivative I tried doing 2 (2x+3)..

*asked on August 20, 2010* -
## math

how do you find the derivative of square root of 5 /t^5

*asked on August 20, 2010* -
## math

how do you find sin7x/4x when lim x goes to 0 the answer is 7/4

*asked on August 19, 2010* -
## math

how does secx(tanx + tan^2x- sec^2x) simplified to sec x (tanx -1)?

*asked on August 19, 2010* -
## math

how do you find the derivative of square root of x

*asked on August 19, 2010* -
## math

I don't know how y-1=-1/3(x-3) is simplifes to x+3y-6=0

*asked on August 17, 2010* -
## math

how do you find the equation of a line knowing (-5,-5) and (-2.-3) so the slope will be 2/3...

*asked on August 14, 2010* -
## math

In the theory of relativity, the mass of a particle with velocity v is m=mo/(square root ((1- v^ 2)/ c^2)) where mo is the mass of the particle at rest and ci s the speed of light. What happens as v goes to c?

*asked on August 13, 2010* -
## math

how do you factor our a cube? x^3 +8

*asked on August 12, 2010* -
## math

evaluate the limit as lim h goes to 0 ((2+h)^3 - 8)/h the answer is twelve but I don't know how to factor out the cube

*asked on August 12, 2010* -
## math

evaluate the limit as lim goes to -1 (x^2 +2x +1)/ (x^4 -1) the answer is zero but i don't know how to get it

*asked on August 12, 2010* -
## math

if f(x)is greater or equal to 10x–42 but less than or equal to x2+2x–26 determine limx4f(x) = What theorem did you use to arrive at your answer?

*asked on August 11, 2010* -
## math

if f(x)is greater or equal to 10x–42 but less than or equal to x2+2x–26 determine limx4f(x) = What theorem did you use to arrive at your answer?

*asked on August 11, 2010* -
## chemistry

Rates of chemical reactions usually depend on temperature and pressure. However, half-life of all radioactive elements is independent of both T and p. How can these decay rates be independent of T if we beleive in the Arrhenius equation?

*asked on July 27, 2010* -
## chemistry

Which of the following salts would show an appreciable pH-dependent solubility? a. AgCl b. Mg(OH)2 c. BaF d. both b and c e. all of the above I put c as my answer (not sure if its right, but can you explain how you would solve this)

*asked on July 27, 2010* -
## chemistry

In titration of a 0.10M soln of Na2Co3 with HCL which of the following will be present in the largest concentration at the first equivalence point? a. Co3^2- b. HCO3- c. H+ d. H2CO3 e. OH-

*asked on July 27, 2010* -
## chemistry

Which of the following when added to 100.0mL of a 0.100M soln of NH4Cl would produce a buffer soln? a.100.0mL of 0.100 M HCl soln b. 100.0mL of 0.050M NaOH soln c. 100.0mL of 0.100M NaOH soln d. 100.0mL of 0.050M NH4No3 soln e.none of the above

*asked on July 27, 2010* -
## chemistry

why is it that [H2O] is NOT included in the rate law, even though it is a reactant?

*asked on July 27, 2010* -
## chemistry

why is it that [H2O] is NOT included in the rate law, even though it is a reactant?

*asked on July 27, 2010* -
## chem

7.50gram quantity of a diprotic acid was dissolved in water and made up to exactly 250ml. If 25ml of this solution were neutralized by 11.1 mL of 1.0 M KOH then what is the molar mass of the acid? I did 7.50/5.55x10^-3

*asked on July 24, 2010* -
## chemistry

Discuss the spontaneity of an electrochemical reaction in terms of its standard emf (E¨¬cell)

*asked on July 22, 2010* -
## chemistry

Solid NaI is slowly added to a soln that is 0.010M in Cu+ and 0.010M in Ag+. a. Which compound will begin to precipitate first? b. Calculate [Ag+] when CuI just begins to precipitate/ c. What percent of Ag+ remains in solution at this point?

*asked on July 19, 2010* -
## chemistry

The amount of indicator used in an acid-base titration must be small. why??

*asked on July 19, 2010* -
## chemistry

the chapter is about chemical kinetics Reaction mechanisms: What does it mean by mechanism of a reaction? What is an elementary step? what is the molecularity of a reaction?

*asked on July 15, 2010* -
## chemistry

Determine the overall orders of the reactions to which the following rate laws apply: a) rate= k[NO2]^2 b) rate = k c) k [H2][Br2]^1/2 d) k [NO]^2[O2] is it.. a. 2 b. 0 c. 1 1/2 d. 3

*asked on July 15, 2010* -
## chemistry

how do you solve this What is the pH of the solution created by combining 2.60 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)? with 8.00 mL of the 0.10 M HC2H3O2(aq)? mL NaOH 2.60 pH wHCl: _ pH wHC2H3O2 : _ Complete the table below: What are

*asked on July 12, 2010* -
## chemistry

how do you solve this? What is the pH of the solution created by combining 12.30 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)? with 8.00 mL of the 0.10 M HC2H3O2(aq)? mL NaOH pH wHCl pH wHC2H3O2 12.30 Complete the table below: What are the

*asked on July 12, 2010* -
## chemistry

Which reactants in the reactions below are acting as Br©ªnsted-Lowry bases? NH4 +(aq) + OH−(aq) NH3(aq) + H2O(l) H2PO4 −(aq) + H2O(l) H3O+(aq) + HPO4 2−(aq) is the answer H2O and the H3O+

*asked on July 6, 2010* -
## chemistry

The pKa for hydrochloric acid is −6.0. What is the concentration of HCl(aq) we would expect to find in a 1 M solution of hydrochloric acid? What pH would we expect? how do you solve this problem?

*asked on July 6, 2010* -
## chemistry

The pH of a 0.0642 M solution of a monoprotic acid is 3.86. s this a strong acid? the answer is no, can you explain why??

*asked on July 4, 2010* -
## chemistry

how do you solve this problem?? how much NaOH (in grams) is needed to prepare 546mL of solution. What is the pOH of the solution?

*asked on July 4, 2010* -
## chemistry

for SCN- if S-C has a bond order of 1, S=C and C=N have bond orders of 2, and C triple bond N hasa bond order of 3, ... Do the bond length in SCN- point to one resonance structure over the other? Which one?

*asked on June 30, 2010* -
## chemistry

how do you know which bonds have a more pie bonding character than the other bond? and how do you know if it point to one resonance structure over the others?

*asked on June 30, 2010* -
## chemistry

how do you know which resonance structure is more stable according to the energy? does higher energy mean more stable?

*asked on June 30, 2010* -
## chemistry

The Fe(ox)33– complex ion creates an emerald green solution when dissolved. The observed solution color of the complex indicates the size of o is: A. large. B. small. C. in between. D. inconclusive, more information is needed. The observed solution color

*asked on June 30, 2010* -
## physics

A skier leaves the end of a ramp with a velocity of 25.3 m/s and lands 50.3 m from the base of the ramp. How high is the end of the ramp from the ground?

*asked on November 9, 2009* -
## Accounting

How does discounted cash flow differ from the other valuation methods?

*asked on January 14, 2009* -
## Middle school Engllish

My son recently had an English test where he was marked incorrectly, but I think he was correct. I just need some verification. The question: "The whole neighborhood watched him climb in his old pickup and ______ down our street at full speed." The word to

*asked on December 16, 2008* -
## Accounting

How does the frequency of interest compounding, regardless of the rate of interest or period of accumulation, affect the future value of any given amount?

*asked on December 15, 2008* -
## science

Would you expect the dissolved oxygen concentration of water samples taken from a lake at 7 am to be higher or lower than samples takn at 5 pm? I feel like there may be more dissolved oxygen in the sample taken at 7 am because photosynthesis probably took

*asked on May 7, 2008*

## Pages

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