[caseykai]

Test for Chemistry chapter 3   8 problems   60 minutes         8-4-12

3.28  Urea [(NH2)2CO] is used for fertilizer and many other things. Calculate the number of N, C, O, and H atoms in 1.68 x 104 g of urea.








3.42 All of the substances listed below are fertilizers the contribute nitrogen to the soil. Which of these is the richest source of nitrogen on a mass percentage basis?

(a) Urea, (NH2)2CO

(b) Ammonium nitrate, NH4N03

(c) Guanidine, HNC(NH2)2

(d) Ammonia, NH3


3.44 Peroxyacylnitrate (PAN) is one of the components c smog. It is a compound of C, H, N, and O. Determine the percent composition of oxygen and the empirical formula from the following percent tom position by mass: 19.8 percent C, 2.50 percent H 1.6 percent N. What is its molecular formula give that its molar mass is about 120 g?









3.60   Balance the following equations using the method outlined in Section 3.7

(h)  Al +  H2SO4 -->  Al2 (SO4) 3 +  H2

(k)  Be2C +  H2O -->  Be(OH)2 +  CH4

(l)  Cu +  HN03 -->  CU(N03) 2 +  NO +  H2O

(n)  NH3 +  Cu0 -->  Cu +  N2 +  H2O
3.70 When baking soda (sodium bicarbonate or sodium hydrogen carbonate, NaHCO3) is heated, it releases carbon dioxide gas, which is responsible for the rising of cookies, donuts, and bread.
(a) Write a balanced equation for the decomposition of the compound (one of the products is NaHCO3)
(


b) Calculate the mass of NaHCO3 required to produce 20.5 g of CO2.




3.72 Fermentation is a complex chemical process of wine making in which glucose is converted into ethanol and carbon dioxide:
C6H12O6 ---> 2C2H5OH + 2 CO2
glucose   ethanol
Starting with 500.4 g of glucose, what is the maximum amount of ethanol in grams and in liters that can be obtained by this process? (Density of ethanol = 0.789 g/mL.)








3.86   Consider the reaction
MnO2 + 4HCl --> MnCI2 + Cl2 + 2H2O
If 0.86 mole of MnO2 and 48.2 g of HCl react, which reagent will be used up first? How many grams of Cl2 will be produced?








3.98 The aluminum sulfate hydrate [Al2(SO4)3 • xH2O] contains 8.20 percent Al by mass. Calculate .x, that is, the number of water molecules associated with
each Al2(SO4)3 unit.

[Arkcon]

Thank you for sharing with us a set of sample questions.  They will certainly come in handy when we need some to practice with.  Might I suggest you take some time to peruse the Forum Rules{click}.  Dumping a bunch of questions, with no work of your own, and expecting use to solve them for you is poor form, indeed.  Although, I have to admit, you didn't even ask us to solve them for you, so anyway, can you try to solve one, as best you can, so we can see what pointers you may need?