posted by Anonymous .
1. Balance the reaction below, then use it to answer the following questions.
a) How many grams of oxygen are needed to make 4.84 moles of water? Is the correct answer 387 grams of O2?
b) How many grams of water will be produced from 3.0 moles of C2H2? Is the correct answer 54 grams of H2O?
2. Aqueous solutions containing 10.0 grams of cupric nitrate and 10.0 grams of ammonium phosphate are mixed together.
a) Write a balanced chemical equation for this double-replacement reaction. Is this correct?: Cu(NO3)3(aq)+(NH4)3PO4(aq)---->3NH4NO3(aq)+CuPO4(s)
b) How many grams of cupric phosphate will be produced? Is the correct answer 6.35 CuPO4?
c) What is the limiting reactant? Is it Cu(NO3)3?
d) Which reactant is in excess and by how much?Is this correct?: (NH4)3PO4; 4.03grams of (NH4)3PO4 remaining
3. Covert,showing proper dimensional analysis and using significant figures: 12.0L=___ mL
My answer is 12,000mL, but there must be 3sig figs.My answer has only 2 sig figs.
4. What is the chemical formula for hydronium?
5. An unknown compound is composed of 71.0% silver, 7.9% carbon, and 21.1% oxygen.
a) Determine the empirical formula for this compound. Is AgCO correct?
b) What is the molecular formula and name of this compound if it has been determined to have the molar mass of 303.8 grams? Is Ag2C2O2 correct?
6. Write a balanced chemical equation (including phases) that represents the reaction that occurs when aluminum metal is dropped into acetic acid. Please show work for this one!!!!!!!!!!
1 a & b are right.
2. Nope. Cupric nitrate is Cu(NO3)2.
3. 12.0 L x (1000 mL/1L) = 12,000 mL. To obtain 3 s.f. you must write it as 1.20E4 mL.
4. I don't know of anything that is simply hydronium (no compound, that is). There is a hydronium ion which is H3O^+.
5a. AgCO is not correct.
Take 100 g sample which give you
71.0 g Ag
Now convert to mols.
71.0/107.90 = about 0.66 mols Ag.
7.9/12 = about 0.66 mols C.
21.l/16 = about 1.32 mol O.
Find the ratio from that. I think it is AgCO2 BUT there is no such compound. This must be a "made up" problem.
b. empirical formula mass AgCO2 = 151.9
303.8/151,l9 = 2 so molecular formula is Ag2C2O4. You know Ag2C2O2 can't be right because that only adds up to 271.8.
6HC2H3O2(aq) + 2Al(s) ==> 2Al(C2H3O2)3(aq) + 3H2(g)