Questions asked by Yann
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How many grams of sodium sulfate (na2so4) are required to make 4.5 liters of a 3.0M solution?

How many mL of a 3.2M NaOH solution is required to neutralize 74mL of a 12.4M HCl solution?

For the equilibrium reaction X + y > XY, the rate of the forward reaction at equilibrium is equal to 1.75 sec^(1). What is the rate of the reverse reaction?

Hydrofluoric acid, HF, has an acid dissociation constant of #6.8 * 10^(4)# at 25 °C. At equilibrium the concentration of HF is 0.025M.
a. What is the equilibrium constant expression for this dissociation?
b. What is the pH of this solution?

Which of the following has highest bond enthalpies?
HF
C=O
HH
N(triple bond)N

Find entropy, enthalpy, Gibbs free energy of reaction at 298K. Find if it is exothermic and whether it is spontaneous?
C3H8 + 502 > 3CO2 + 4H2O

Use Hess's Law and the following information to calculate the change in enthalpy for the reaction 2C + H2 > C2H2?

Find overall reaction for a galvanic cell that will have the highest cell potential. What is the overall potential of the cell?
Which two equations do I use?

Help!
Let f(x) be a function with domain [3, ∞ ) and range ( ∞ , 2). If g(x) = f^1 (x) (aka. g(x) is the inverse of f(x)), then what is the domain of g(x+4)7 ?

Simplify the following?
csc(arctan(sec(arccos(3/5))))

If cot (π/2  x) = 3/4 , what is sec^2(x)?

Find all angles x [0, 2π), such that cos(2x) = 2sin(x) = 3
?

What is the inverse of the function #f(x) = 7log_4(x+3)  2#?
It is #7log_4 (x+3)  2#, if that clears any confusion.

Use#cos(x/2) * cos(x/4) * cos(x/8)# and the half angle formula #[cos(A/2) = sqrt(1+cosA)/2]# to show #2/π = sqrt(2)/2 * (sqrt(2+sqrt2))/2 ...#
How?

Let z = 1i. Find abs(z) ... How?

Solve for x: tan^3(x)  3tan(x) = 0
Solve for [0, 2π) ... How?

Solve for x:
arctan(x) = arccos(5/13)
Solve for [0, 2π)... How?

Solve: x^(3) = 8 How do I solve for x?

Urgent!
The polynomials #ax^33x^2+2x3# and #ax^25x+a# when divided by #x2# leave remainders of #p# and #q# respectively. Find the value of #a# if #p=3q#. How? Urgent thanks!

Urgent! Help! A cubic polynomial has zeros at x=1, x=1, and x=3. It has a yintercept of 6. What is the remainder when we divide this polynomial by x^2+1 ??

Help! Use GaussJordan elimination (row reduction) to find all solutions to the following system of linear equations?
2x + 3y  z = 3
 x + 4y = 9
4x  y  z = 7
How? Help!

Let P(x) be a real polynomial of degree ≤4 such that there are at least 5 distinct solutions to P(x) = 5. Find P(5). How???

If f(x) = 2x + 1 and g(f(x)) = 4x^2 + 4x + 3 , find g(x), given that g(x) is in the form of ax^2 + bx + c. How?

Urgent! There is a ferris wheel of radius 30 feet. When the compartments are at their lowest, it is 2 feet off the ground. The ferris wheel makes a full revolution in 20 seconds. Using a cosine function, write an equation modelling the height of time?

Help! Rotate the axis to eliminate the xyterm in the equation then write the equation ins standard form.
x^24xy+4y^2+5sqrt(5)+1=0
Help!?

Help! Rotate the axis to eliminate the xyterm in the equation then write the equation ins standard form. #x^24xy+4y^2+5sqrt(5)y+1=0# Help!?

What are [computer] keyboards made of? As in materials used in keys or the board itself.
Thanks!

When ammonium sulfate is heated with solution X, ammonia gas is given off. Is solution X HCl or NaOH?

If you cover the tip of a shoot in opaque black aluminium foil, towards which direction does the shoot grow?
Or does it even grow at all?

Find the area bounded by the curve y=e^(x/3) , the tangent line which is y=1/3 e^(3)x  2e^3 and the xaxis?

There are usually fewer stomata found on the upper surface of a leaf. Suggest why this is beneficial to a plant?

What burns to produce one product?
What does not change litmus paper (either way)?
a. carbon dioxide
b. carbon monoxide

How many even numbers less than 500 can be formed using the digits 1,2,3,4,5? Each digit can only be used once.

The fundamental frequency of a closed tube is the same frequency as the 2nd harmonic of a stretched string. The mass per unit length of the string is 6.10x10^4 kg/m. The tension in the string is 48.0N...?

How do you transform y=1/x to y= (3x2)/(x+1) ?

Assuming that all of the elastic potential energy is transferred to kinetic energy, what speed will a 0.57kg ball leave a spring that is compressed 0.13m?

A 2.6kg car is rolling down a frictionless incline that makes an angle of 23º to the horizontal. The initial speed of the car is 4.3m/s. What is the speed of the car 26m down the incline?

Could someone explain the lewis structure diagram of covalent compound Al2Cl6?

The summit of mount everest can be at a temperature of 50ºC and the pressure at its summit is roughly 1/3 that at sea level. The density of air at sea level is about 1.25kg/m^3. Calculate the density of air at the top of the mountain?

The temperature of a fixed mass of an ideal gas goes from 40ºC to 80ºC at a constant volume. If the initial pressure was x, what is the new pressure?

Calculate the meansquare speed, of krypton atoms in a sample of gas at a temperature of 22ºC?

The molar mass of carbon dioxide is 0.045kg/mol. Calculate the density of the gas when the temperature is 273K and the pressure is 120000Pa..?