Answer:
![[A]_0=0.400M](https://tex.z-dn.net/?f=%5BA%5D_0%3D0.400M)
Explanation:
Hello.
In this case, since the first-order reaction is said to be linearly related to the rate of reaction:
![r=-k[A]](https://tex.z-dn.net/?f=r%3D-k%5BA%5D)
Whereas [A] is the concentration of hydrogen peroxide, when writing it as a differential equation we have:
![\frac{d[A]}{dt} =-k[A]](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BA%5D%7D%7Bdt%7D%20%3D-k%5BA%5D)
Which integrated is:
![ln(\frac{[A]}{[A]_0} )=-kt](https://tex.z-dn.net/?f=ln%28%5Cfrac%7B%5BA%5D%7D%7B%5BA%5D_0%7D%20%29%3D-kt)
And we can calculate the initial concentration of the hydrogen peroxide as follows:
![[A]_0=\frac{[A]}{exp(-kt)}](https://tex.z-dn.net/?f=%5BA%5D_0%3D%5Cfrac%7B%5BA%5D%7D%7Bexp%28-kt%29%7D)
Thus, for the given data, we obtain:
![[A]_0=\frac{0.321M}{exp(-2.54x10^{-4}s^{-1}*855s)}](https://tex.z-dn.net/?f=%5BA%5D_0%3D%5Cfrac%7B0.321M%7D%7Bexp%28-2.54x10%5E%7B-4%7Ds%5E%7B-1%7D%2A855s%29%7D)
Best regards!
Answer:
109.7178g of H2O
Explanation:
First let us generate a balanced equation for the reaction. This is illustrated below:
2C3H8O + 9O2 —> 6CO2 + 8H2O
Next we will calculate the molar mass and masses of C3H8O and H20. This is illustrated below:
Molar Mass of C3H8O = (3x12.011) + (8x1.00794) + 15.9994 = 36.033 + 8.06352 + 15.9994 = 60.09592g/mol.
Mass of C3H8O from the balanced equation = 2 x 60.09592 = 120.19184g
Molar Mass of H2O = (2x1.00794) + 15.9994 = 2.01588 + 15.9994 = 18.01528g/mol
Mass of H2O from the balanced equation = 8 x 18.01528 = 144.12224g
From the equation,
120.19184g of C3H8O produced 144.12224g of H20.
Therefore, 91.5g of C3H8O will produce = (91.5 x 144.12224) /120.19184 = 109.7178g of H2O
Answer is: a) in the presence of a base.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions.
Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations.
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄).
When solution turns phenolphthalein pink, it means it is basic (pH>7).
The answer is C. They lower the activation energy of an elementary step of a reaction
This makes the reaction rate to increase since less energy is required to make a reaction occur.
