Indicate which of the following reactions results in a positive ASsys. 2 Na(s) +Cl, (g) NaCl(s) b. Zn(s)+2 HCl(aq) 5 ZnCl, (aq) +H, (g) 4 Fe(s) + 3 0, (g) 5 2 Fe,O,(s) d. 2 H, (g)+0,(g) 5 2 H,0(g) Ba(NO,),(aq) + Na, SO,(aq) 5 BaSO,(s) + 2 NaNO, (aq) a. c. e.

Balance the following reaction. If a reactant or product is not present, put a zero (0) in the blank. 1.  H+(aq) + H2O(l) + Cr+4(aq) + e-1 <--> Cr+3(g) + H+(aq) + H2O(l) 2. H+(aq) + H2O(l) + I-1(aq) + e-1 <--> I-1(g) + H+(aq) + H2O(l)

One way to determine the hardness of a water sample is to precipitate the calcium out of solution as a carbonate.  The net ionic reaction for this precipitation is:                         Ca2+(aq)  +  CO32-(aq)  →  CaCO3 (s)   A 1.00 L sample of water is drawn from a Phoenix, AZ well and 0.534 g of calcium carbonate is recovered using the above reaction. What was the Ca2+ concentration of the original water sample in ppm? Show your work and include units.  Hint:  ppm stands for parts per million, and in the case of an aqueous solution, this is equivalent to mg/L.

Balance the following reaction. If a reactant or product is not present, put a zero (0) in the blank.  H+(aq) +  H2O(l) +  ClO-13(aq) +  e-1 <-->  Cl-1(g) +  H+(aq) +  H2O(l)

Which reaction below is NOT a redox reaction O 2H2 (g) + O2 (g) →2H2 O(1) O H2 SO4 (aq) + 2 N2OH(aq) →2H2 O(1) + Na2 SO4 (aq) O Cu(s) + 2AGN03 (aq) →2Ag(s) + Cu(NO3)2(aq) 2CO(g) + O2 (g) –→2CO2(g)

Aspirin can be synthesized in the lab by combining salicylic acid (C,H,O,) and acetic anhydride (C,H,0,) to form aspirin ( C,H,O,) and acetic acid (C, H, 0,). The balanced equation for this reaction is C,H,O, + C,H,0, C,HgO, + +C,H,O, A student started with 3.49 mL acetic anhydride (density = 1.08 g/mL) and 2.09 g salicylic acid. The student synthesized 2.14 g of aspirin. Select the limiting reactant. acetic anhydride (C,H,O,) acetic acid (C,H,O,) O salicylic acid (CH,O,) O aspirin (C,HO,) Calculate the theoretical yield of aspirin (C, HO,). theoretical yield: Calculate the percent yield for aspirin (C,H,O). percent yield:

Classify each chemical reaction: reaction Na, S (aq) + FeCl, (aq) → 2NaCl(aq) + FeS (3) CuSO, (aq) + ZnCro, (aq) ZnSO₂ (aq) + CuCrO₂ (s) KOH(aq) + HBrO(aq) - KBrO(aq) + H₂O(1) CH,(CH,),CH_() + 8O,(8) -- 5CO,(g) + 6H,O(g) type of reaction (check all that apply) combination single replacement double replacement decomposition combination single replacement double replacement decomposition combination single replacement double replacement decomposition combination single replacement double replacement decomposition precipitation combustion acid-base precipitation combustion acid-base precipitation combustion acid-base precipitation combustion acid-base

Balance the following reaction. If a reactant or product is not present, put a zero (0) in the blank. H+(aq) + H2O(l) + ClO-13(aq) + e-1 <--> Cl-1(g) + H+(aq) + H2O(l)

Aspirin can be synthesized in the lab by combining salicylic acid (C,H,0,) and acetic anhydride (C,H,O,) to form aspirin ( C, H,O,) and acetic acid (C,H,O,). The balanced equation for this reaction is C,H,O, + C,H,O, → C,H¿O4 + C,H,O, A student started with 4.02 mL acetic anhydride (density of aspirin. = 1.08 g/mL) and 2.41 g salicylic acid. The student synthesized 2.41 g Select the limiting reactant. acetic anhydride (C,H,O,) salicylic acid (C,H,0,) O acetic acid (C,H,O,) aspirin (C,H¿O,) Calculate the theoretical yield of aspirin (C,H,O4). theoretical yield: g Calculate the percent yield for aspirin (C,H,O4). percent yield:

Write the net ionic equation, including phases that corresponds to the reaction  Cu(ClO4)2(aq) + K2CO3(aq) yields to CuCO3(s) + 2KClO4(aq)