The AP Chemistry Study Thread

I’m guessing it’s Zn, Mg, Ca, Na, K, Cs.



What is Gibbs free energy and if delta S is positive, it is spontaneous?

[stanford_dude]

Gibbs free energy is the energy available in the universe for work. If ΔS is positive, that means the entropy is positive and therefore IS SPONTANEOUS. Entropy is the randomness/disorder of the universe, or as my teacher likes to say...spreadiness.

EDIT: I forgot. It also depends on the ΔH. If ΔH is negative and ΔS is positive, the reaction is spontaneous. If ΔS is positive and ΔH is positive, a process is spontaneous at high temperatures, where exothermicity plays a small role in the balance.

[stanford_dude]

Oh yeah my question.

Name all five tenets of Dalton's Atomic Theory.

* Elements are made of tiny particles called atoms.
* All atoms of a given element are identical.
* The atoms of a given element are different than those of any other element.
* Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers of types of atoms.
* Atoms are indivisible in chemical processes. Atoms are not created nor destroyed in chemical reactions. A chemical reaction simply changes the way atoms are grouped together.

Is delta S is negative, is it automatically nonspontaneous no matter what delta H is?

[mrniceguy]

deltaG = delta H - T delta S

No, as long as delta H is very negative (very exothermic), the reaction can be spontaneous. (rxns are spontaneous if delta G is negative).

Q: Alpha, beta, and gamma particles: which type is most penetrating?

gamma particles

Describe Rutherford's experiment.

[Oboesmrtguy40]

his atomic theory describes the atom as having a central positive nucleus surrounded by negative orbiting electrons.

1. A two bulbed flask contains four particles. What is the probability of finding all four particles in only one of the bulbs?


A 0.0625 %

B 0 %

C 6.25 %

D 11.3 %

E 25 %

1/16 or 0.0625.




Four of the following factors can affect the forward rate of a chemical reaction.
Which one cannot affect this rate?
1) temperature
2) particle size of solid reactants
3) concentration of reactants
4) presence of a catalyst
5) removal of some of the products

[Oboesmrtguy40]

^^^ wrong, it was 6.25

(so ur question cant be answered yet)

1. Which of the following statements is true?


A In a spontaneous process, DG has a positive value

B The entropy of the universe is increasing

C Exothermic reactions are always spontaneous

D A system at constant temperature cannot experience entropy changes

E For a process to be spontaneous, the number of moles of product must exceed the number of moles of reactant

0.0625 = 6.25%

[Oboesmrtguy40]

oh sorry lol im out of it

[Oboesmrtguy40]

answrr to ur question quickquiz is choice 2) particle size of solid reactants

It’s ok. Yeah I put 2 for that one too. You can the next question ...

[Oboesmrtguy40]

1. Which of the following statements is true?


A In a spontaneous process, DG has a positive value

B The entropy of the universe is increasing

C Exothermic reactions are always spontaneous

D A system at constant temperature cannot experience entropy changes

E For a process to be spontaneous, the number of moles of product must exceed the number of moles of reactant

[stanfordream]

how would you calculate the probability? assuming the 2 bulbs are the same, i would think that at equilibrium, all gases are present in both bulbs, with the denser gases at the bottom.