c# barcode reader from image Gases 119 in C#.NET

Recognize Data Matrix 2d barcode in C#.NET Gases 119

You have 20 minutes to do the following question You may use a calculator and the tables at the back of the book A hydrogen gas sample is collected over water The volume of the sample was 1900 mL at 26 C, and the pressure in the room was 754 mm Hg The vapor pressure of water at 26 C is 252 mm Hg a Calculate the number of moles of hydrogen in the sample b Calculate how many molecules of water vapor are present in the sample c Determine the density (in g/L) of the gas mixture d Determine the mole fraction of water

You have 20 minutes to do the following questions You may not use a calculator You may use the tables in the back of the book A sample containing 2/3 mole of potassium chlorate, KClO3, is heated until it decomposes to potassium chloride and oxygen gas The oxygen is collected in an inverted bottle through the displacement of water Answer the following questions using this information a Write a balanced chemical equation for the reaction b How many moles of oxygen gas are produced c The temperature and pressure of the sample are adjusted to STP The volume of the sample is found to be slightly greater than 224 liters Explain d An excess of sulfur is burned in the oxygen Write a balanced chemical equation and calculate the number of moles of gas formed e After the sulfur had completely reacted, a sample of the residual water was removed from the bottle and found to be acidic Explain

a Ptotal = 754 mm Hg Phydrogen = 754 252 = 729 mm Hg P = 729 mm Hg/760 mm Hg = 0959 atm V = 1900 mL = 01900 L T = 26 C = 299 K 1 1 R = 00821 L atm mol K n = PV/RT 1 1 = (0959 atm 01900 L)/(00821 L atm mol K 299 K) = 000742 mol H2 Give yourself 1 point for the correct answer (no deduction for rounding differently) You must include all parts of the calculation (including = )

Give yourself 1 point for the correct equation, or for any other correct calculation Do not give yourself more than 2 points total for this part b Pwater = 252 mm Hg/760 mm Hg = 00332 atm T and V are the same as in part a 23 1 Avogadro s number = 6022 10 molecules mol = N n = PV /RT 1 1 = (00332 atm 01900 L)/(00821 L atm mol K 299 K) 4 = 257 10 mol H2O) 4 23 1 molecules = (257 10 mol) (6022 10 molecules mol ) 20 = 155 10 molecules Give yourself 1 point for the correct answer (no deduction for rounding differently) You must include all parts of the calculation (including = ) Give yourself 1 point for the correct equation, or for any other correct calculation Do not give yourself more than 2 points total for this part c (000742 mol H2) (2016 g H2/mol H2) = 00150 g H2 (257 10 4 mol H2O) (1802 g H2O/mol H2O) = 000463 g H2O total mass = 00150 g H2 + 000463 g H2O = 00196 g density = 00196 g/01900 L = 0103 g/L Give yourself 1 point for the correct answer (no deduction for rounding differently) You must include all parts of the calculation (including = ) Give yourself 1 point for the correct equation, or for any other correct calculation Do not give yourself more than 2 points total for this part

4 d 000742 mol H2 and 257 10 mol H2O 4 total moles = (000742 + 257 10 ) = 000768 mol 4 Mole fraction H2O = (257 10 mol H2O)/(000768 mol) = 00335

Give yourself 1 point for the correct answer (no deduction for rounding differently) You must include all parts of the calculation (including = ) Give yourself 1 point for the correct equation, or for any other correct calculation Do not give yourself more than 2 points total for this part Total score = sum of parts a d If any of the final answers has the incorrect number of significant figures, subtract one point