Copper metal (Cu(s)) is immersed in an aqueous solution of silver nitrate (AgNO3). The solution turns light blue and a silver coating appears on the copper.
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First need to determine the species originally present and their formulae:
Cu(s), Ag+(aq), NO3-(aq), Cu2+(aq), Ag(s). -
From the description, silver metal is made, so we can write the unbalanced reaction:
Cu(s) + Ag+(aq) + NO3-(aq)
Cu2+(aq) + NO3-(aq) + Ag(s) -
By inspection we see that the atoms are balanced, however charges are not. Balancing charge we get:
Cu(s) + 2 Ag+(aq) + NO3-(aq) Cu2+(aq) + NO3-(aq) + 2 Ag(s) -
Finally, canceling species present on both sides gives:
Cu(s) + 2 Ag+(aq) Cu2+(aq) + 2 Ag(s)
Dilute solutions of antimony(III) chloride and sodium sulfide are mixed to give a precipitate.
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First need to determine species originally present and their formulae:
Sb3+(aq), Cl-(aq), Na +(aq), S2-(aq). -
Since we know sodium chloride is soluble we can write the unbalanced reaction:
Sb3+(aq) + 3 Cl-(aq) + Na +(aq)+ S2-(aq) 3 Cl-(aq) + Na +(aq) + Sb2S3 (s) -
By inspection we see that the atoms are not balanced, we need to add one antimony and two sulfides on the left:
2 Sb3+(aq) + 3 Cl-(aq) + Na +(aq)+ 3 S2-(aq) 3 Cl-(aq) + Na +(aq) + Sb2S3 (s) -
Finally, canceling species present on both sides gives:
2 Sb3+(aq) + 3 S2-(aq) Sb2S3 (s)
Dilute solutions of silver nitrate and potassium iodide are combined and give a yellow precipitate.
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We know that potassium nitrate is soluble (there are no insoluble nitrates nor potassium salts), so the precipitate must be silver iodide:
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Ag+(aq) + NO3-(aq) + K +(aq) + I-(aq)
K +(aq) + NO3-(aq)+ AgI(s) -
Ag+(aq) + I-(aq)
AgI(s)
Dilute solutions of aluminum chloride and sodium hydroxide are mixed, giving a gelatinous precipitate.
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We know that sodium chloride is soluble, so the precipitate must be aluminum hydroxide:
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Al3+(aq) + 3 Cl-(aq) + Na +(aq) + OH-(aq)
3 Cl-(aq) + Na +(aq) + Al(OH)3(s) -
Al3+(aq) + 3 OH-(aq)
Al(OH)3(s)
Dilute solutions of calcium chloride and sodium phosphate are combined to give a precipitate.
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We know that sodium chloride is soluble, so the precipitate must be calcium phosphate:
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Ca2+(aq) + 2 Cl-(aq) + 3 Na +(aq) + PO43-(aq)
2 Cl-(aq) + 3 Na+(aq) + Ca3(PO4)2 -
3 Ca2+(aq) + 2 PO43-(aq)
Ca3(PO4)2
Dilute solutions of nitric acid and sodium hydroxide are mixed, generating heat.
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This is an acid-base reaction, so water will be formed.
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H+(aq) + NO3-(aq) + Na+(aq) + OH-(aq)
NO3-(aq) + Na+(aq) + H2O(l) -
H+(aq) + OH-(aq)
H2O(l)
Dilute solutions of sulfuric acid and sodium hydroxide are mixed, generating heat.
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This is an acid-base reaction, so water will be formed. Bisulfate is a weak acid.
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H+(aq) + HSO4-(aq) + Na+(aq) + OH-(aq)
SO42-(aq) + Na+(aq) + H2O(l) -
H+(aq) + HSO4-(aq) + 2 OH-(aq)
SO42-(aq) + 2 H2O(l)
A dilute solution of hydrochloric acid is poured over limestone (calcium carbonate) and a non-flammable, odorless gas is released as the rock dissolves.
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From the description, the most likely gas is carbon dioxide.
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H+(aq) + Cl-(aq) + CaCO3(s)
Ca2+(aq) + Cl-(aq) + CO2(g) + H2O(l) -
2 H+(aq) + CaCO3(s)
Ca2+(aq) + CO2(g) + H2O(l)
Dilute solutions of lead(II) nitrate and sodium chloride are combined and give a white precipitate.
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We know that sodium nitrate is soluble (there are no insoluble nitrates nor sodium salts), so the precipitate must be lead chloride:
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Pb2+(aq) + 2 NO3-(aq) + Na+(aq) + Cl-(aq)
Na+(aq) + 2 NO3-(aq + PbCl2 (s) -
Pb2+(aq) + 2 Cl-(aq)
PbCl2 (s)
Dilute solutions of barium chloride and sodium sulfate are combined to give a white insoluble precipitate.
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We know that sodium chloride is soluble, so the precipitate must be barium sulfate:
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Ba2+(aq) + 2 Cl-(aq) + 2 Na +(aq) + SO42-(aq)
2 Cl-(aq) + 2 Na+(aq) + BaSO4 -
Ba2+(aq) + SO42-(aq)
BaSO4