CHEMISTRY COMMUNITY

aristotelis1H

When solving for q water = -nC p,water ΔT, why is ΔT solved by doing (T f - 20 o C), when we should convert the 20 o C to 293K in order to cancel out units of the molar heat capacity of water (75.5 J/Kmol)?? I tried doing the calculation with 293K, in order to properly cancel out the units, and I ge...

aristotelis1H

When using the calculation ΔG = -RTlnK will we be given the energy values for the different confirmations. For example, when solving for Gauche Butane ↔ Anti Butane, will we be told that Gauche Butane is 0.9 kcal/mol and anti butane is 0? Or should we have some values memorized?

aristotelis1H

For a reaction to be considered an electrophilic aromatic substitution (EAS), does it have to involve a benzene ring? Or would the reaction without a benzene ring (but still a cycloalkene) be considered an electrophilic addition reaction? Basically I am wondering if the two reaction terms are the sa...

aristotelis1H

The answer would be 2-isopropyl-1,1-dimethylpentane because it is better to have two 1's rather than two 2's (we want the lowest possible numbers in the answer). Alphabetical order does not determine the numbering and the first substituent does not need to have the lowest number.

aristotelis1H

When drawing the electron-flow arrows for reaction mechanisms, do we always have to indicate the dipole of the molecule(s) (by writing either δ - or δ + ) to explain why we are drawing the arrows if the question just states to "complete the reaction mechanism" or "used curved arrows t...

aristotelis1H

"Determine the rate constant for each of the following first-order reactions, in each case ex[ressed for the rate loss of A: ... (b) A->B, given that the concentration of A decreases from 0.67 mol/L to 0.53 mol/L in 25 s" Why would you use ln\left ( \frac{[A]_{o}}{[A]_{t}} \right )...

aristotelis1H

"Suppose 64.0 gram each of methyl alcohol, CH 3 OH (MW 32.0 g/mol) and ammonia, NH 3 (MW 17.0 g/mol) are allowed to react according to the above equation at 298 K and constant pressure. What is the heat q of the reaction?" I understand that we must first calculate the moles of the reaction...

aristotelis1H

"Q7B. Determine the equilibrium constant for the reaction: Mn (s) + Ti +2 (aq) --> Mn 2+ (aq) + Ti (s) " After balancing the half reactions, I got: Mn (s) -> Mn 2+ (aq) + 2e - 2e - + Ti +2 (aq) --> Ti (s) When using lnK = \fra...

aristotelis1H

When askedd to balance skeletal equations by using oxidation and reduction half-reactions, these half-reactions will be given to us? Because in some of the homework questions I could not find certain half-reactions. For example, the following half-reaction is not in Appendex 2, A 18 C 2 H 5 OH (...

aristotelis1H

I thought this was a cute image :)

aristotelis1H

Because a change in temperature, whether in Kelvin or in Celsius, will still result in the same difference (since changing to Kelvin you just add 273 to both temperature values, it will make no difference in your answer).

aristotelis1H

"9.45 Use the information in Table 8.3 to calculate the changes in entropy f the surroundings and of the system for (a) the vaporization of 1.00 mol CH 4 (l) at its normal boiling point; (b) the melting of 1.00 mol C 2 H 5 OH(s) at its normal melting point; (c) the freezing of 1.00 mol C 2 H 5 ...

aristotelis1H

In some homework questions, the value of n in q = nCΔT is assumed to be equal to 1; however, when using w = $-nRT\mathit{ln}\frac{V2}{V1}$ you must solve for n by PV = nRT.
Why is this and is this always the case?

aristotelis1H

"8.25 A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q = -3.50 kJ), resulting in a temperature rise of 7.23 o C. In a subsequent experiment, 100.0 mL of 0.200 M HBr (aq) and 100.0 mL of 0.200 M ...

aristotelis1H

"8.3 Air in a bicycle pump is compressed by pushing in the handle. If the inner diameter of the pump is 3.0 cm and the pump is depressed 20. cm with a pressure of 2.00 atm, (a) how much work is done in the compression? (b) is the work positive or negative with respect to the air in the pump (c)...

aristotelis1H

HW question 8.65 asks "Calculate the standard enthalpy of formation of dinitrogen pentoxide from the following data, 2NO(g) + O 2 (g) -> 2NO 2 (g) ∆H o = -114.1 kJ 4NO 2 (g) + O 2 (g) -> 2N 2 O 5 (g) ∆H o = -110.2 kJ and from the standard enthalpy of form...

CHEMISTRY COMMUNITY

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2010 Final Q1A

Confirmation Energy Differences

EAS vs. Electrophilic Addition Reaction

Re: Naming Structures

Drawing Reaction Mechanisms & Arrows

Homework 15.23 part (b)

Winter 2014 Midterm 1B

Winter 2012 Midterm Question 7B

Half-Reactions

Re: Chemistry Jokes

Re: Homework Question 8.25

Homework 9.45

value of n in w= -nRT*ln(V2/V1) vs. q=nCΔT

Homework Question 8.25

Homework Question 8.3 part (c)

HW 8.65