Official SAT Subject Test - Chemistry - June 2015

Guys, I think I understand the density question. Density CAN affect the temperature, because Charles’s law states that temperature and volume are directly related. Since density is mass/volume, we can change the density by changing the volume, which we can do by changing the temperature. However, IF VOLUME IS CONSTANT, I don’t think density will be effected by volume. So I think the answer was density, but I’m not sure.

Density = mass/volume. At constant volume, the mass will never change due to temperature. Thus the mass and volume are both constant. So yea, just admit you answered a question wrong. There’s no need to argue on over like 5 pages.

Yeah I don’t know why we are spending so much time over one question. I thought it was a relatively straightforward question and I’ve seen something similar in a Practice test I took

There was a ttce question about the bonding in f2 being different from n2. What did you guys put?

N2 is triple bond f2 is single

I don’t think that was ttce, nitrogen has triple bonds and fluorine only has single. I think it was either FT or TF @ssapbio

Ok good. I couldn’t tell if it was referring to covalent vs ionic or triple bond vs. single bond.

Oh shoot. I got another question wrong.

Yep, definitely not getting an 800.

@topaz116 I don’t think colleges will see much of a difference between a 770-800, at least most of them

The Nitrogen and Fluorine bonds were both the same bonds (it said so in the problem). My answer was therefore F/F

I think 750+ is all around the same but if you submit 2 or 3 subject tests and all of them are 800 that definitely looks more impressive

Do you guys know about the question where it said N2is hard to break up or something and what was the force? It was one of the questions where the next question’s answer was covalent bond.

I think it said N2 can be made into a solid. It was dispersion forces. There was an exactly similar question(except with H2) in the blue book, and the answer to that was dispersion as well. @SnickerShaker

Ok awesome! What about the question where it said a solution with a pH above two but below 6…I wrote HC2H3O2

To address the above questions:

  1. The enthalpy change is -795 kJ. 2(-240) + (-400) - (-85) = -795
  2. C + CO2 is an example of a CONDENSATION reaction. The key here is that condensation is another word for synthesis, not liquid turning into a gas. I got this question wrong and looked it up afterward.
  3. N2 only forms dispersion forces since it is nonpolar.
  4. You can't heat a graduated cylinder because it will crack
  5. H2 and O2 can be used in water separation techniques, however HCL cannot because it dissolves in water.

I also got two more questions wrong and later found out that:

  1. Cl2 is not the strongest oxidizing agent, flourine is the strongest oxidizing agent
  2. Adding salt to water does affect the vapor pressure

Hope this helps!

To add on:

  1. Temperature is definitely a function of kinetic energy. The definition of temperature is literally average kinetic energy, so if temperature increases, so does energy. Think about this logically: a burning hot fire has more energy than a piece of ice.

Adding salt does affect vapor pressure. It decreases it.

Was it tt ce? For the vapor pressure one

No

Was 10^50 an answer for one