CHEMISTRY COMMUNITY

Yi Ying Chen 3N

Here, "n" represents the number of electrons in the balanced half reactions. In this question, our half reactions are: (Fe \rightarrow Fe^{2+} + 2e^{-}) \times 2 <-- we multiply this one by 2 to balance out the electrons and 4e^{-} + 2H_{2}O + O_{2} \rightarrow 4OH^{-} Hope that he...

Yi Ying Chen 3N

Hello, I have a question regarding one of the questions in quiz 2. The question is: Consider the following reaction at equilibrium. A\rightleftharpoons B+C The equilibrium concentration were measured as follows: [A] = 0.0100M, [B] = 0.500M, [C] = 2.50M In a kinetic experiment, the rate constant of t...

Yi Ying Chen 3N

ATTENTION! A new element has been discovered!

Yi Ying Chen 3N

I hate dealing with triple bonds. They cause alkyne-ds of problems.

Yi Ying Chen 3N

It cannot be cyclopropane, because all cycloalkanes have the general molecular formula of $C_{n}H_{2n}$
Meanwhile, CH3-CH2-CH3 has 3 carbons and 8 hydrogens, so it is a propane, which follows the general formula of $C_{n}H_{2n+2}$ for alkanes.

Yi Ying Chen 3N

No, the units for reaction rates do not change. They remain as M/sec or M/min (depending on what unit you use to measure time)
On the other hand, the units for rate constants (k) do change depending on the order of the reaction.

Yi Ying Chen 3N

Ea and temperature are related by the Arrhenius equation:
$lnk = lnA - \frac{Ea}{RT}$
The higher the activation energy, the stronger is the temperature dependence of the rate constant k.

Yi Ying Chen 3N

The "2.303" comes from writing the Nernst equation in log base 10 rather than in ln:

$lnQ = \frac{logQ}{loge} = \frac{logQ}{\frac{lne}{ln10}} = ln10\times logQ = 2.303logQ$

It's sometimes more convenient to use log base 10, like when you're dealing with pH.

Yi Ying Chen 3N

Yeah, I'm also getting 1.21 x 10^-22.
Perhaps there's an error in the course reader?

Yi Ying Chen 3N

My high school chemistry teacher taught me this trick to remember that reduction takes place at the cathode and oxidation takes place at the anode.

reduction, cathode = RED CAT
anode, oxidation = AN OX

Yi Ying Chen 3N

A bomb calorimeter measures the heat released in a reaction. A sample is placed in the sealed metal container (the "bomb"), which is immersed in water. The bomb is ignited electrically by a fuse wire, allowing the sample inside to combust. Once combustion has begun, energy released as heat...

Yi Ying Chen 3N

For that diagram, A refers to the area of the top of the cylinder (the circular part).
If you multiply that area by the distance the piston moves due to external pressure, you'd get the change in volume.

Yi Ying Chen 3N

The 40.7 degrees celsius value would be used when we're dealing with water at its boiling point (100 degrees celsius), as mentioned at the bottom of pg 283. The standard reaction enthalpy only indicates that the reactants and products are in their standard state (pure form at 1 bar/atm). Since tempe...

CHEMISTRY COMMUNITY

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