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Chemistry Regents January 2008 - Question 72 |
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Written by The Chemistry Wizard
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If you refer to the table of Common acid-base indicators, you can see that bromthymol blue tests blue in a base and yellow in an acid, and methanol is not an acid or a base, so bottle mustbe methanol.
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Last Updated on Friday, 13 March 2009 18:22 |
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Chemistry Regents January 2008 - Question 74 |
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Written by The Chemistry Wizard
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.jpg) If the pH of a solution is great than 4.4 (the only information we receive from the test), it could still be acidic, basic, or neutral. In this case, all three solutions would yield the same evidence which is not enough to distinguish between them.
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Last Updated on Thursday, 05 March 2009 05:00 |
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Chemistry Regents January 2008 - Question 73 |
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Written by The Chemistry Wizard
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.jpg) Bromthymol blue would yield a yellow test result for an acid.
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Chemistry Regents January 2008 - Question 65 |
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Written by The Chemistry Wizard
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About 63 grams.
Refer to Table G and observe the change in the solubility curve for KNO3 when the solution moves from 65C to 15C. Remember that there are originally 90grams of KNO3.
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Last Updated on Friday, 13 March 2009 18:23 |
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Chemistry Regents January 2008 - Question 64 |
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Written by The Chemistry Wizard
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Unlike temperature and concentration, pressure does not have an effect on the solubility. Table G
Solubility Curves shows the correlation between temperature and concentration with solubility.
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Last Updated on Friday, 13 March 2009 18:23 |
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Chemistry Regents January 2008 - Question 14 |
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Written by The Chemistry Wizard
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(1) BaCO3 is the correct answer.
Barium carbonate is insoluble in water. Solubility table F lists ions that form insoluble compounds in water, one of which is carbonate (CO3). The ions which comprise the other choices are all listed as water soluble compounds.
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Chemistry Regents January 2008 - Question 24 |
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Written by The Chemistry Wizard
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(3) H3PO4 is the correct answer.
Phosphoric acid is the correct answer because an Arrhenius acid is a substance that when added to water increases the concentration of H+ ions present. In this case, phosphoric acid will dissociate to produce H+ ions in water.
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Chemistry Regents January 2008 - Question 25 |
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Written by The Chemistry Wizard
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4) KOH is the correct answer.
When added to water, KOH dissociates into K+ and OH- (hydroxide) ions.
You can refer to Table E to review the polyatomic ions.
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Chemistry Regents January 2008 - Question 46 |
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Written by The Chemistry Wizard
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(4) 30 mL is the correct answer.
In this equation, you want an equal number of moles on each side of the equation and since the molar ratio is 1:1, the math is quite simple.
.1M x (xmL) = .2 M x (15 mL)
X= 30
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Last Updated on Wednesday, 04 March 2009 10:22 |
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Chemistry Regents January 2008 - Question 47 |
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Written by The Chemistry Wizard
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(2) bromthymol blue is the correct answer.
If you refer to table M, Common Acid-Base Indicators, you will see that bromthymol blue
changes from yellow to blue between pH of 6.0-7.6.
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Last Updated on Wednesday, 04 March 2009 10:22 |
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