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Chemistry help please
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1) Alkanes combusts to CO2 and H2O, and Methane(CH4) has 1 C, and 4 H's, so it can make one CO2 and two H2Os, requiring a total 4 Oxygen atoms per one CH4 molecule combusted. Since CH4's molar weight is 16 grams, 32 grams would have 2 moles of CH4, which means that 2x4 = 8 moles of Oxygen atoms are needed. Since each KCLO3 makes 3 Oxygen atoms, a total of 8/3 moles of KClO3 is needed. The answer is C.
2) SO2 has a pair of unbound electrons on the S atom, so it is the polar on e(similar logic to NO2's polarity). The answer is A.
3) Boron has 3 valence electrons, and in BCl3 it is bound to 3 Cl's, so you need 3 equal orbitals. The only answer that hybridizes to 3 equivalent orbitals is sp2. The answer is B.
2) SO2 has a pair of unbound electrons on the S atom, so it is the polar on e(similar logic to NO2's polarity). The answer is A.
3) Boron has 3 valence electrons, and in BCl3 it is bound to 3 Cl's, so you need 3 equal orbitals. The only answer that hybridizes to 3 equivalent orbitals is sp2. The answer is B.
4) A 25% decrease in pressure means the new P is 3/4 the old P, which would cause the volume to increase by a factor of 4/3. Doubling requires the volume to increase by a factor of 2, which is 6/3. This means that it has to increase by an additional factor of (6/3) / (4/3) = 6/4 = 3/2. Since volume and temperature are directly proportional, an increase of 3/2 for volume would require an increase of 3/2 for temperature. The temperature at STP is 273, and 3/2 x 273 ~= 410. The answer is D.
5) You need to find out the ionic concentration of each molecule/compound, and the one with the highest ionic concentration would have the greatest boiling point elevation and therefore the highest boiling point. A has 0.4m after Na and Cl dissociate, B has 0.4m as well, C does not dissociate so it's still 0.1m, D dissociates to 0.4m(an H comes out, though its relatively low acidity would actually make it far less than 0.4m), E dissociates to 0.6m. Thus, E is the answer.
6) The hydration of CO2 does not involve exchange of H or OH of any sort, so you can rule out the Bronsted-Lowry choices. As for which one is a Lewis base and which is a Lewis acid, I always use a simple little trick. I consider electrons to be "opposites" of H+ ions, so we all know many acids donate a H+, so they would accept(the opposite of donate) electrons. Now, since the carbon in CO2 doesn't have any electron to donate, water must be the donator of electrons. And since donators of H+'s would be acids, donators of electrons must be bases. Thus, water donates electrons, and acts as a base, giving you D as the answer.
There's an easier way to do this. After eliminating the Bronsted-Lowry choices, and since acids and bases occur in pairs, A and E would have to both be true if either is true, thus you can eliminate them. That leaves D as your answer.
5) You need to find out the ionic concentration of each molecule/compound, and the one with the highest ionic concentration would have the greatest boiling point elevation and therefore the highest boiling point. A has 0.4m after Na and Cl dissociate, B has 0.4m as well, C does not dissociate so it's still 0.1m, D dissociates to 0.4m(an H comes out, though its relatively low acidity would actually make it far less than 0.4m), E dissociates to 0.6m. Thus, E is the answer.
6) The hydration of CO2 does not involve exchange of H or OH of any sort, so you can rule out the Bronsted-Lowry choices. As for which one is a Lewis base and which is a Lewis acid, I always use a simple little trick. I consider electrons to be "opposites" of H+ ions, so we all know many acids donate a H+, so they would accept(the opposite of donate) electrons. Now, since the carbon in CO2 doesn't have any electron to donate, water must be the donator of electrons. And since donators of H+'s would be acids, donators of electrons must be bases. Thus, water donates electrons, and acts as a base, giving you D as the answer.
There's an easier way to do this. After eliminating the Bronsted-Lowry choices, and since acids and bases occur in pairs, A and E would have to both be true if either is true, thus you can eliminate them. That leaves D as your answer.
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d
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- Pre-Medical
What chemistry resources are you using? When are you taking your MCAT? You should be able to answer these questions quite easily using a chem text. Are you asking us to do your homework? 
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she's wanting us to help her get a job at TPR
Good luck getting past training....you won't make it if you have to poll SDN for the answers
Good luck getting past training....you won't make it if you have to poll SDN for the answers
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Seriously? Are those tests not timed and taken in a classroom?
At any rate, posts deleted. Thanks.
At any rate, posts deleted. Thanks.
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They are supposed to be taken under timed conditions but sometimes the pdf's are sent out. It's not a big deal because the master trainer would never clear someone like this that tried to get certified
