Ch. 9 & 13 stoichiometry & gas [50 points] Honors Chemistry
For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.
1. What is the mass of the precipitate formed by mixing aqueous solutions containing 100.0 g silver nitrate and 100.0 g copper (II) nitrate ? [15 points]
2. A 2.0 L container at STP has 4.0 g H2 , 40. g O2 , and 60. g N2 . What is the partial pressure of O2 ? [10 points]
3. H2 O2 (aq) --> H2 O (l) + O 2 (g)
How many grams of H2O2 would decompose if there was 5.0 L O2 at 25 °C and 1.0 atm formed in the above reaction ? [15 points]
4. What is the % yield in the chemical reaction: excess N2 + 5.0 g H2 --> 20.0 g NH3 ? [10 points]
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Ch. 9 & 13 stoichiometry & gas retest [50 points] Honors Chemistry
1. What is the mass of the precipitate formed by mixing aqueous solutions containing 100.0 g calcium nitrate and 100.0 g sodium phosphate ? [15 points]
2. A container at STP has 4.0 g H2 , 40. g O2 , and 60. g N2 . [10 points]
a. What is the partial pressure of O2 ?
b. what is the volume of the container ?
3. A 35 mg sample containing copper and magnesium was added to HCl, where
Mg (s) + excess HCl (aq) --> MgCl2 (aq) + H2 (g)
where got 35 mL gas (assume PH2O = 20 mm Hg & ΔP = 0) at 22 °C and 0.95 atm; HCl does not react with Cu.
What is the % Cu in the sample before HCl treatment ? [15 points]
4. The % yield in the chemical reaction: N2 + H2 --> NH3 is 80 %. How much H2 (there is excess N2 ) is needed to form 15.0 grams of NH3 ? [10 points]