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 Assume you had a [x] g block of pure iron metal that fully oxidized and the mass of the rust product produced was [y] g.  What must have been the mass of oxygen that initially reacted with pure iron? unbalanced chemical equation is : __Fe(s) + __O2 –> __Fe2O3   Write answer with one place after the decimal.

Copper metal reacts with aqueous hydrobromic acid to produce copper (II) bromide and hydrogen gas.   Cu (s) + 2 HBr (aq) –>  CuBr2 (aq)  +  H2 (g)   What volume of 2.50 M HBr is required to produce 45.0 L of hydrogen gas at a temperature of 298 K and a pressure of 1.00 atm? 

Below are a list of gases.  If 1.4 moles of each gas were placed into a 2.5 L balloon each, which balloon, after several days, will remained filled the most?  Assume that the material that makes up the balloon itself are the same.

Consider the following equation.  2 H2 (g) + O2 (g)  –> 2 H2O (g)   If 8.00 moles of H2 (g) react fully with oxygen how many moles of water will be made? Assume an excess amount of Oxygen.  The answer must have the correct significant figures ( 1 pt) and unit ( 1 point) . Circle your final answer.  All work must be shown for credit. No work=no credit. All work must in your own hand-writing.  

Zinc metal reacts with aqueous hydrochloric acid to produce zinc chloride and hydrogen gas. Zn (s) + 2 HCl (aq) –>  ZnCl2 (aq)  +  H2 (g) What volume of 3.55 M HCl is required to produce 25.5 L of hydrogen gas at a temperature of 298 K and a pressure of 1.20 atm?   

When a gas condenses, it releases heat to its surroundings.  This is a(n)                             process.

Explain the difference between a saturated solution and a concentrated solution. 

Identify the BrØnsted base in this reaction.  H2O (l) + HNO3 (aq)  –>  H3O+ (aq)  + NO3- (aq)

Write  1) complete Ionic equation ( 4pts)  and 2) net ionic equation ( 4pts)  for this neutralization reaction: H2SO4 (aq)  + 2KOH(aq) –> K2SO4(aq)  + 2H2O(l)   All work must be shown for credit. No work=no credit. All work must in your own hand-writing.  

Ozone has the formula O3.  Which statement is correct concerning ozone?