Official SAT Subject Test - Chemistry - June 2015

@garybarry i got 10^50 too, because didnt it ask for the largest product or something?

Does anyone know when the scores will be released?

@Luckyrunner5 june 25

what was 10^50 for? I don’t remember that question?

@ErnieBachJr a condensation reaction is not quite a synthesis reaction; it involves the loss of a smaller molecule (such as water), which does not happen in C + O2 -> CO2. Also, the question did not ask about C + CO2, but rather the formation of CO2 from C

MY HUMPS MY LOVELLY LITTLE LUMPS

@Homsar thanks

What was the N2 vs F2 ttce? I got F/F

@Arpeggio206 what was the question? (i didn’t take the test this time, i took it last year. i’m just an ap kid trying to help out :P)

I believe it was the bonds between N2 was stronger than F2 if both double bonds (I’m questioning myself about that ) because N2 is more electronegative than F2. I know that the latter is false but i dont remember if i read the first part correctly because N2 is usually a triple bond

Can someone confirm that the question stated that both bonds were double bonds.

@Arpeggio206 n2 and f2 usually have triple and single bonds, respectively. but yes, usually n2 bonds are stronger than f2 bonds.

Ik but i think it said in the directions for us to assume that both bonds were double bonds (maybe i derped)

@Arpeggio206 to be safe, i looked up bond enthalpies online. the n2 double bond enthalpy is somewhere around ~400 kj. i couldn’t find the bond enthalpies for the f2 double bond, but i think it’s weaker.

@apactstudent When CO2 dissolves in water, it forms H2CO3, which then dissociates to form an acidic solution. This is true for nearly all nonmetal oxides.
Adding a strong acid to an aqueous solution of the carbonate ion forms H2CO3. However, because of the strong acid, the H2CO3 is unable to dissociate as it would like, so it instead breaks down into CO2 and H2O.

@xexvc0302 I love questions like this because they trip up those who only memorize formulas.
Density = (mass) / (volume). Obviously, the amount does not change. In a rigid container, the volume will remain constant, regardless of temperature. Changes in temperature in a rigid container, however, will change the pressure. By Guy Lussac’s Law, the ratio of P to T must be constant. Looking back at your equation, P is in the numerator and T is in the denominator. Note that the other terms are constant as well.
So, in a rigid container with a fixed volume, the density will not change.
@Arpeggio206 Increasing the temperature of a system increases the average speed of the particles. This corresponds to an increase in the energy of the system.

F is the most electronegative element, so f2 is stronger than n2

@Arpeggio206 @michelle426 The reason you can’t find the double-bond energy for F2 is that the F nuclei are too small to make a double-bond viable. The nuclei repel each other too much to get that close.
@i2400ezpz While it is true that F is more electronegative, the F2 nuclei repel each other so much that a pi bond forms instead of a sigma bond. This bond readily breaks when electrons are available.

What do you guys think the lowest score would be to get a 700? And anyway ya’ll got the question all mixed up. The first statement: The bonds in F2 are easier to break than the bonds in N2.
Statement 2: F is more electronegative than N.
So it’s TT.

A raw score of 61-64, i’d say