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ID: 1038644 • Letter: I
Question
Insert Format ToolsTable WindowHelp Post Lab Gases(1) Design Layout References Mailings Review View 1 u .abex, x2 A, ? . A,'? ! :-.d ,-, styles Styies Pane Gwinnett Technicall College CHEM 1211 Laboratory Post Lab: Gases Name: . Date: Submit this page at the beginning of the lab period If the total pressure of water vapor and hydrogen gas is 1.02 atm and the partial pressure of the water at 22.0 C is 0.13 1. m, what is the pressure of the hydrogen gas? 2. a. Calculate the theoretical yield of hydrogen gas (in L) at 295 K for a reaction of 1.50 s magnesium with excess hydrochloric acid b. If1.205 L of gas is produced, what is the percent yield of the reaction? 3. What is a possible (non-human) error that could lead to a low percent yield? 4. What is a possible (non-human) error that could lead to a percent yield over 100? 130 words English (US)Explanation / Answer
1) P(total) = 1.02 atm; P(H2O) = 0.13 atm
P(H2) = P(total) - P(H2O) = 0.89 atm
2a) Mg + 2HCl ----> MgCl2 + H2
1 mole of Mg = 1 mole of H2
24.3 g of Mg = 22.4L of H2 (molar volume at STP)
1.5g of Mg = 22.4×1.5/24.3 = 1.382 L
2b) given actual yeild = 1.205L,
% yeild = (1.205/1.382)×100 = 87.19%
3. Possible errors are : reactions may be incomplete; side reactions may have occurred giving undesired product; loss of product during separation and purification from reaction mixture; impurities in reactant itself which do not react.
4. Possible errors: yeild over 100% indicates product obtained is not pure. The impurity contributes to the weight of the product measured.