s10q09 - 1. Chem 171 Quiz 9 Version A (Key Antacid...

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Chem 171 Quiz 9 Version A (Key Antacid Enthalpy) 1. A student adds 2.500 x 10 -2 moles of HCl to an antacid tablet whose mass is 1.500g. To back-titrate the sample, the student uses 5.000 x 10 -3 moles of NaOH. If the bottle of antacid tablets cost $2.50 and contains 50 tablets what is the cost effectiveness of this tablet (per one cent). Write the relevant molecular equation (show the states). Na =22.99. O = 16.00. H = 1.008. HCl (aq) + NaOH (aq) Æ NaCl (aq) + H 2 O (l) Moles of HCl used to neutralize the antacid = 2.500x 10 -2 - 5.000 x 10 -3 = 2.000 x 10 -2 Cost per tablet = 250 cents / 50 tablets = 5 cents per tablet C = 2.000 x 10 -2 mol HCl / 5 cents = 4.000 x 10 -3 moles HCl/cent 2. What is the definition of Enthalpy of a system? What is the definition of Change in Enthalpy? The enthalpy of a system is defined as the internal energy plus the product of the pressure and volume, H = E + PV The change in enthalpy is the change in internal energy plus the product of the constant pressure and the change in volume, Δ H = E+P V Chem 171 Quiz 9 Version B 1. The active ingredient in Rolaids is dihydroxyaluminum sodium carbonate, Al(OH)
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This note was uploaded on 03/08/2011 for the course CHEM 171 taught by Professor Several during the Spring '08 term at Rutgers.

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s10q09 - 1. Chem 171 Quiz 9 Version A (Key Antacid...

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