<p>I would be happy to help anybody who needs help with SAT II Chemistry. Ask away.</p>
<p>How can you tell if a compound is an acid or base?
Specifically,
Na2S + H2SO4 ----> H2S + Na2SO4,
2Na3PO4 + 3H2SO4 -----> 2H3PO4 + 3Na2SO4,
Na2CO3 + H2SO4 -----> H2CO3 + Na2SO4
NaOH + H2SO4 -----> H2O + Na2SO4</p>
<p>How am I supposed to know Na2S, Na3PO4, and Na2CO3 are bases?</p>
<p>I can never tell if a substance is acid or base when it doesn’t contain an H. Can you please provide me a general rule?</p>
<p>…AlCl3(aq) + …NH3(aq) + …H2O -></p>
<p>Which of the following is one of the products obtained from the reaction above?
A) AlN
B) AlH3
C) Al
D) Al(NO3)3
E) Al(OH)3</p>
<p>Answer is E. You know why? </p>
<p>A 0.1 molar solutiuon of hich of the following compounds has the lowest hydrogen ion concentration?</p>
<p>A) HCl
B) AlCl3
C) NaHCO3
D) NaOH
E) HC2H3O2</p>
<p>Why isn’t the answer B? It doesn’t even have an H.</p>
<p>Thanks a lot in advance</p>
<p>To tell if something is an acid or a base, look at the anion and cation.
For example, NaCl is neutral because NaOH is strong and HCl is strong
Na2S is a base because NaOH is strong and H2S is weak
The strong bases are the alkali and alkaline cations with -OH
Strong acids are HCl HBr HI H2SO4 HClO4 H3PO4 and HNO3</p>
<ol>
<li>HCl + H20 –> H3O^+ + Cl^-
This is the Bronsted Lowry method of acid base chemistry
H3O^+ is called the hydronium ion it is often shortened to H^+
When an acid or a base dissociated, it forms hydronium ions or hydroxide ions. It is a base if it forms OH^- and an acid if it forms hydronium. Strong acids and strong bases dissociate completely. Weak acids and weak bases dissociate partially. NaOH is a strong base, so it will form no hydronium ions. Don’t be fooled by hydrogens meaning hydrogen atoms.
pH = -log[H3O^+] in other words, the concentration of hydronium ions. NaOH will have the lowest concentration of hydronium ions, that is why it is basic.</li>
</ol>
<p>I can almost guarantee that you will have a question on the test that says something like this:
H2SO4 is a stronger acid than HF because H2SO4 has more hydrogen atoms
It would be true true but not CE. Don’t get fooled by this.</p>
<p>AlCl3 + 3H2O + 3NH3 -> Al(OH)3 + 3NH4Cl</p>
<p>1) Wait so you’re saying… to figure out if compound is an acid or base, I need to separate the said compound to an anion and cation (say NaCl to Na+ and Cl-), add an OH and H to the anion and cation, respectively, and calculate the pH from there?</p>
<p>If so, using that logic would mean
strong acid + weak base -> weak acid
strong base + weak acid -> weak base
strong acid + strong base -> neutralization
weak acid + weak base -> neutralization</p>
<p>right?</p>
<p>I’m sorry if I’m confusing you lol. It’s just that I’ve never heard of your explanation before. Please tell me if I successfully comprehended what you were saying. If I didn’t, please elaborate more, or link me a site that explains how to differentiation between acid/base.</p>
<ol>
<li><p>I guess my question is really, how did you know the answer would be E in the first place? Sure you can balance everything out, and then say “it makes sense!”, but is there a quicker way to identify the answer’s E?</p></li>
<li><p>Gotcha</p></li>
</ol>
<p>Nevermind, I just read [SparkNotes:</a> SAT Chemistry: Acid?Base Reactions: Neutralization Reactions](<a href=“SparkNotes: Today's Most Popular Study Guides”>SparkNotes: Today's Most Popular Study Guides), and I understand how to tell if a compound is an acid or base w/o an H or OH.</p>
<p>I still don’t know how you would approach #2 though.</p>
<p>I’ll post up more questions, if I have any (or if you’re still around).</p>
<p>How many oxygen atoms are there in 0.50 moles of KHSO4
The answer is 1.2*10^24</p>
<p>There are 6.02X 10^23 atoms in a mole of Oxygen, so there are 3.01X10^23 atoms in .5 moles. Just divide by two. Next, you multiply it by for, because that is how many Oxygen atoms are in KHSO4. That will give you 1.2X10^24</p>
<p>Sorry to answer this so late.</p>
<p>This is probably one of the hardest actual SAT Subject Test Chemistry questions I’ve seen…</p>
<p>In an electrolysis cell, the passage of 6.02x10^23 electrons can produce
(A) 22.4 liters of H2 gas (measured at standard conditions) from dilute H2SO4 solution
(B) 22.4 liters of O2 gas (measured at standard conditions) from dilute H2SO4 solution
(C) 1 mole of Cl2 gas from HCl solution
(D) 1 mole of metallic silver from AgNO3 solution
(E) 1 mole of metallic copper from CuSO4 solution</p>
<p>Help would be appreciated if you can get this one. :)</p>
<p>6.02x10^23 electrons is just one mole of electrons.</p>
<p>Half reaction of the formation of Ag is Ag + electron –> Ag^-</p>
<p>That is one electron. Is the answer D?</p>
<p>Would you recommend Barrons to study for this test? I have a solid 3 weeks to study from it and am looking at a 600-800 score. Took the class a while ago, only remembering subtly some concepts.</p>
<p>A 0.1 molar solutiuon of hich of the following compounds has the lowest hydrogen ion concentration?</p>
<p>A) HCl
B) AlCl3
C) NaHCO3
D) NaOH
E) HC2H3O2</p>
<p>First of all, imagine each of these placed in water (the question says its dilute). Choice (B), AlCl3, ionizes and thus the partial charges attract H+ ions. Choice (C) doesn’t ionize.</p>
<p>[C]</p>
<p>The answer is actually D. As far as books go, I am really not sure which one is best.</p>
<p>Yes, it was D. Thanks.</p>
<p>SAT is coming up. Anyone need anymore help?</p>
<p>Please if you can help where I can get practice questions or provide suitable link.</p>
<p>Many thanks in advance</p>
<p>I hear some people use sparknotes. I have never actually used sparknotes though.</p>
<p>i’m practicing with a sparknotes book, and i came across this question
the following hydrogen halides (HF, HCl, HBr, and HI) are all polar. The strength of the acid each forms in water is based on which of the following?</p>
<ol>
<li>the polarity of the molecule
II. the size of the molecule
III. the strength of the bond</li>
</ol>
<p>I answered I and III, but the book says its II and III…could someone please help me? thank youu</p>
<p>could someone please answer this question and the one above…</p>
<p>which of these actions will cause more kno3 to be dissolved in a saturated potassium nitrate solution?
I. grind the potassium nitrate and then add to mix while stirring.
II. add more kno3 while using a magnetic stirrer.
III. add more kno3 and heat the solution.</p>
<p>the book says its only II…but I thought it would be I and III…what do you guys think?</p>