CHEMISTRY COMMUNITY

Anuk Burli 2C

Hi When drawing a chair structure especially for a ring flip is it necessary to draw in all the hydrogens?

Anuk Burli 2C

Hi 7E on 2014 asks to draw the most stable Newman projection for 3-chloro-4,4,4- trihydroxy-3-methylbutanenitrile. The answer key says that the C(OH)3 has to be gauche to both hydrogens but I drew this. Why is this incorrect?

Anuk Burli 2C

When you draw the line structure for propene does it matter where you put the double bond? Is there a specific reason the answer key put the double bond between the second and the third carbon?

Anuk Burli 2C

I'm not sure about part a but for part b I believe that inert noble gases don't affect the rate of the reaction so they wouldn't be included. I don't think you ever add noble gases because they're inert similar to how they didnt affect equilibrium

Anuk Burli 2C

we would use the method of half reactions to solve this problem so our two half reactions would be F2 +2e- = 2F- which has a value of 2.87 V and F2+2H+ + 2e= 2HF which has a value of 3.03 V HF is a weak acid so does not dissociate completely so it dissociates into HF=H+ +F- so the Ka for this reacti...

Anuk Burli 2C

I know Hess's Law is generally given in kJ, bond enthalpies tend to be given in kj/mol, I think Gibb's free energy is given in KJ in a hess's law type of calculation, standard reaction enthalpies in kj/mol, standard reaction entropies in j/mol.

Anuk Burli 2C

Are isothermal processes always reversible? If the question doesn't specify if the process is reversible but it says it's isothermal do we assume that it's reversible?

Anuk Burli 2C

Hi

So PV=nRT and density = mass over volume and n=mass (m)/ molar mass (M) so PV=m/M (RT) so divide both sides by RT and then divide both sides by V so you get P/RT=m/M *V and m/v is density so you get P/RT=D/M so multiply both sides by M to get MP/RT = Density

Anuk Burli 2C

Hi

They're not saying the specific heat is negative they're using q system + q surroundings =0 so q system= - q surroundings so they just distributed the negative sign in q surroundings to the specific heat of water.

Anuk Burli 2C

Hi,

I think the units should be kj/mol for standard enthalpy of reaction. However, in calorimetry problems where it is not asking for standard enthalpy of reaction the unit can just be kj.

Anuk Burli 2C

Hi,

I think it's just a typo because if you leave entropy and enthalpy both as negative and plug it in you get the same answer of 55.40 kj/mol

Anuk Burli 2C

Hi

Yah I think if they don't give you temperature assume it to be 25 degrees C or 298 K

Anuk Burli 2C

correct me if I'm wrong but I'm pretty sure Delta E has the same formulas as delta U which is q+w

Anuk Burli 2C

The way to remember any problem like these kind of calorimeter problems is to think of it in terms of the first law of thermodynamics where any heat released by the system has to be absorbed by the surroundings or aka q system + q surroundings=0. As long as you correctly identify the system and the ...

Anuk Burli 2C

Hi I believe that the larger the molecule for similar types of bonding such as HCN and HBR the larger the molecule the higher the heat capacity. You also have to take into account that certain equations can predict heat capacities. For example Cp for monatomics is 5/2 R where R is the ideal gas cons...

Anuk Burli 2C

also an important implication of state functions is that according to hess's law a series of reactions of state functions can be summed up to generate a new value for the overall reaction. Examples of these state functions would be enthalpy, entropy, and Gibb's free energy (H, S, and G). However, yo...

Anuk Burli 2C

Hi Net Ionic equations are where you remove spectator ions in a reaction or the ions that are exactly the same on both sides of the reaction aka they were present in the reaction but did not actually participate in the reaction. To write a net ionic equation: Write the balanced molecular equation, t...

Anuk Burli 2C

Hi,

The graph would look like a plateau as in the concentration of the products (aka K+) would start at 0 and then rise and level off at the middle of the graph.

Anuk Burli

Anuk Burli 2C

Hi

I'm not sure if they will be on the final but some other solvents could be methanol, isopropanol, benzene.

Anuk Burli

Anuk Burli 2C

Hi!

I believe that that's correct where Arrhenius and Bronsted is a reaction with water but I believe that lewis acids and bases don't necessarily have to be in water. For example PF5 +F- = Pf6 is a lewis acid-base reaction.

Anuk Burli 2C

Hi There are 3 definitions of acids and bases. Arrhenius, Bronsted Lowry, and Lewis. If you draw the lewis structure and it can accept an electron then it is a lewis acid but if it can donate an electron it is a lewis base. If it is a Bronsted-Lowry acid it is a proton donor and if it is a base it i...

Anuk Burli 2C

Hi. If the reaction is endothermic, then heat is absorbed which means that heat is on the reactant's side. If temperature is increased then the reaction would shift to the right favoring production of the products.

Anuk Burli 2C

Hi
I think you use the net ionic equation when most of the reactants and products are ions or in aqueous solution

Anuk Burli 2C

In case you wanted to know though, I think if Delta G or Gibb's free energy is negative then K is larger and if Delta G is positive then K will be small. This is due to the equation Delta G= -RTln(K)

Anuk Burli 2C

Hi, From what I think, the molecule is made up of 5 sp3d orbitals. three of these orbitals are arranged around the center which contain the 3 lone pairs. However 2 of the orbitals are arranged at 90 degrees from the three other orbitals. So while the electron arrangement is trigonal bipyramidal, the...

Anuk Burli 2C

Hi,

The most stable lewis structure is the one where each element has the lowest formal charge or the formal charge closest to 0.

Anuk Burli 2C

Hi,

We use resonance because of the limitations of a single lewis structure. The bonds aren't actually alternating between single, double, and triple bonds but resonance structures are a way to show the average bond length that a single lewis structure cannot show.

Anuk Burli 2C

Hi, if the quantum number n is equal to 6 and the quantum number l is equal to 3 then you know that those two quantum numbers correspond with 6f. There are 7 orbitals for f. You add 2 orbitals for each level. For example s has 1 orbital, p has 3 orbitals, d has 5 orbitals and f has 7 orbitals.

Anuk Burli 2C

Hi, The magnetic spin quantum number refers to the angular momentum of an electron. Angular momentum is a vector so it has magnitude (1/2) and direction (+/-). The electrons "spin" a certain direction because electrons tend to fill orbitals before they pair up. If there are two electrons i...

CHEMISTRY COMMUNITY

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