<p>okay so I have a question:</p>
<p>Which of the following are true regarding the aqueous dissociation of HCN, Ka = 4.9 x 10-10 at 25 oC?
i. At equilibrium, [H+] = [CN-]
ii. At equilibrium, [H+] = [HCN]
iii. HCN is a strong acid
a. i only
b. ii only
c. i and ii only
d. ii and iii only
e. i, ii and iii</p>
<p>Also,</p>
<p>What is the H3O+ concentration of a 0.100 M acetic acid solution (Ka = 1.8 x 10-5)?
a. 1.8 x 10-5
b. 1.8 x 10-4
c. 1.3 x 10-2
d. 1.3 x 10-3
e. 0.9 x 10-</p>
<p>It says the answer is D </p>
<p>HOW COME?!?!
LIKE ISN’T the conc equal k of a? so it should be choice a!!?!</p>
<p>@Savvy123
Do you mean when am I taking the Sat II? In November. Good luck on your SAT Physics!</p>
<p>A. Radioactive isotope
B. Monoclinic crystal
C. Sulfur trioxide
D. Sulfate salt
E. Allotropic form
19. A substance that exhibits a resonance structure.</p>
<p>I answered C simply because I remembered seeing a resonance diagram of SO3. Otherwise, I wouldn’t know how to identify which compound has a resonance structure. Is there a way to do that? </p>
<p>I’m also confused about how pressure affects temperature of water. How come when you answered this question:
When the pressure drops sufficiently, the water starts to boil.
BECAUSE
At the boiling point, the vapor pressure of the water equals the pressure inside the bell jar.</p>
<p>You said that as pressure drops, molecules will be free to move around, so water will boil. Is it because the temperature will increase, or this doesn’t affect the temperature? Normally, the temperature should decrease if pressure decreases. (P/T = k). Also, “changes in pressure are directly related to the boiling point of water” so boiling point of water should be lowered if pressure is lowered. This is so confusing!</p>
<p>Also, how do you know if salt is strong acid or not? Do you look at each element and what it forms? For example, NaNO3. You say, Na will form NaOH, and NO3 will form HNO3. Therefore, strong acid+weak base; so the salt is acidic? If you have KF. You say K will form KOH, and F will form HF, therefore strong base+weak acid = basic salt? </p>
<p>For which of the following is pH likely to affect solubility?
BaSO4
BaF2
CaCO3
MnS
AuCl3</p>
<p>Answer is only the three middle ones. Why?</p>
<p>Question asks to balance this:
Cu(s) + HNO3(aq) → Cu(NO3)2 (aq) + H2O(l) + NO(g)
Is there an easier method, because it’s too hard…</p>
<p>A gas at STP that contains 6.02*10^23 atoms and forms diatomic molecules will occupy
A. 11.2 L
B. 22.4 L
C. 33.6 L
D. 67.2 L
E. 1.06 qt</p>
<p>I don’t understand what they’re asking… Wouldn’t it be clearer if they said: "a gas that contains 6.02*10^23 in its diatomic state will occupy in its monoatomic state: "</p>
<p>“The position from which silver that is plated out emerges” This is talking about electroplating of a metallic spoon. So, Ag+ are provided by the anode, and they are attracted to the cathode, where they become reduced, and plate the spoon. Right? But what does “plated out” mean? Answer is: “Solution of Ag+ ions”. But I don’t understand how silver that is “plated out” emerges from the solution of Ag+ions?? If anything, silver is the “plator” not “plated”.</p>
<p>HCl has polar covalent bond? How would I know that? Do they give you the electronegativities on the test?</p>
<p>The reaction of CaCO3 and HCl goes to completion
BECAUSE
reactions that form a precipitate tend to go to completion.</p>
<p>Answer is T,T btw.
So, is the gaseous product formed: CaCl2 ? or HCO3 (bicarbonate) ?</p>
<p>A student measured 10 mL of an HCl solution into a beaker and titrated it with a standard NaOH solution that was 0.09M. The initial NaOH burette reading was 34.7 mL while the final reading showed 49.2 mL. What is the molarity of the HCl solution?
I don’t understand; during titration, does the NaOH volume increase? why did it go from 34.7 mL to 49.2mL, and why does the book say that the difference of those two numbers is the amount of volume of NaOH used?</p>
<p>Which of the following does NOT react with a dilute solution of sulfuric acid?
NaNO3
Na2S
Na3PO4
Na2CO3
NaOH</p>
<p>I thought NaOH won’t react because it’s a strong base. Strong base + Strong acid = No Reaction, right? Why is the answer NaNO3? Book says because it requires heat to react. How would I know what requires heat to react…There’s another question where they eliminated SO3 because it requires heat to react. I want to know how they know what requires heat to react and what does not.</p>
<p>Is it just me, or are my questions totally invisible?</p>
<p>Which of the following are true regarding the aqueous dissociation of HCN, Ka = 4.9 x 10-10 at 25 oC?
i. At equilibrium, [H+] = [CN-]
ii. At equilibrium, [H+] = [HCN]
iii. HCN is a strong acid
a. i only
b. ii only
c. i and ii only
d. ii and iii only
e. i, ii and iii</p>
<p>Is it C? I is true because in HCN -> H+ + CN-, the two products have the same mole number, and so will have the same number of moles in 1L, which is another way of saying same Molarity, or same concentration. II is true because at equilibrium, the concentration of the products and reactants are almost equal. III I believe is wrong because Ka is relatively small; for strong acids Ka > 1.</p>
<p>What is the H3O+ concentration of a 0.100 M acetic acid solution (Ka = 1.8 x 10-5)?
a. 1.8 x 10-5
b. 1.8 x 10-4
c. 1.3 x 10-2
d. 1.3 x 10-3
e. 0.9 x 10-</p>
<p>Make a table.
HC2H3O2 → H3O+ + C2H3O2-
Initial 0.1 0 0
Change -x +x +x
Final 0.1 - x x x</p>
<p>Ka = (x<em>x)/(0.1-x) = 1.8</em>10^-5
x = 1.33 * 10^-3
D is the answer.</p>
<p>Now, can someone please answer My invisible questions.</p>
<p>Which of these pieces of laboratory glassware should NEVER be heated with a Bunsen burner?
A. Beaker
B. Graduated cylinder
C. Flask
D. Test tube</p>
<p>Can we say that in general, boiling point increases, freezing point decreases with increased molar mass?</p>
<p>The colors in compounds are due to the compound not absorbing a certain wavelength or are they due to the compound’s electrons moving to a higher level and then going back to their energy level??</p>
<p>Come on, please someone answer this and my other questions (on the third page)! The test is in 3 days…</p>
<p>“Which of these pieces of laboratory glassware should NEVER be heated with a Bunsen burner?
A. Beaker
B. Graduated cylinder
C. Flask
D. Test tube” </p>
<p>B</p>
<p>never heat a graduated cylinder. The heat can crack the glass destroying the measurements.</p>
<p>So…no one’s gonna answer? C’mon, please…</p>
<p>Which of the following are true regarding the aqueous dissociation of HCN, Ka = 4.9 x 10-10 at 25 oC?
i. At equilibrium, [H+] = [CN-]
ii. At equilibrium, [H+] = [HCN]
iii. HCN is a strong acid
a. i only
b. ii only
c. i and ii only
d. ii and iii only
e. i, ii and iii</p>
<p>^Answer is A. HCN is a weak acid.
HCN → H+ + CN-
The concentration of the product ions, in this case, [H+] and [CN-] will be the same.</p>