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Miniature Laboratory Volcano Empirical Formula

63. A miniature laboratory volcano can be made with ammonium dichromate. When ignited it decomposes in a fiery display. (NH4)2Cr2O7(s) N2(g) +4 H2O(g) + Cr2O3(s). If 5.0g of ammonium dichromate are used and if the gases from this reaction are trapped in a 2.0 L flask at 25oC, what is the total pressure of the gas in the flask? What are the partial pressures of N2 and H2O?

85. A xenon fluoride can be prepared by heating a mixture of Xe and F2 to a high temperature in a pressure-proof container made of nickel. Assume that xenon gas was added to a 0.25 L container until its pressure was 0.12 atm at 0.0oC. Fluorine gas was then added until the total pressure was 0.72 atm at 0.0oC. After the reaction was complete, the xenon had been consumed completely and the pressure of the F2 remaining in the container was 0.36 atm at 0oC. What is the empirical formula of compound prepared from Xe and F2?

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(NH4)2Cr2O7(s) = N2(g) + 4H2O(g) + Cr2O3(s)

Molecular weight of (NH4)2Cr2O7 =2*(14+4)+2*52+7*16=252(g/mol)
Number of mole of (NH4)2Cr2O7 =5/252=0.0198 (mol)
The number of mole of N2 produced = 0.0198 (mol)
The number of mole of H2O ...

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