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@oliviad57 • 4 months ago • Chemistry • 5 pts

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Popular Chemistry Practice Problems

1.560 x 10-4 mol of an unidentified gaseous substance effuses through a tiny hole in 98.8 s.

Under identical conditions, 1.749 x 10-4 mol of argon gas takes 84.9 s to effuse. 

What is the molar mass of the unidentified substance (in g/mol)? 

The percentage C by mass in the above unidentified substance is 53.0%. It may also contain H and/or O, but no other element. 

What is the molecular formula of the substance? 

In typing this formula use the convention of C first, H second and O last. For example, C6H8O2 would be C6H802.) 

Under identical conditions, how many moles of acetylene (C2H2) gas would effuse in 86.5 s? 

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Enter your answer in the provided box. 

The vapor pressure of ethanol is 100 mmHg at 34.9°C. What is its vapor pressure at 64.5°C? 

(ΔHvap for ethanol is 39.3 kJ/mol.) 

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A sample of an ideal gas has a volume of 3.15 L at 10.20°C and 1.50 atm. What is the volume of the gas at 20.80°C and 0.987 atm?  

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For the reaction

H2 (g) + C2H(g) → C2H6 (g)  

ΔG° = -100.7 kJ and ΔS° = -120.7 J/K at 301 K and 1 atm. 

This reaction is (reactant, product) ____________ favored under standard conditions at 301 K.

The standard enthalpy change for the reaction of 2.40 moles of H2(e) at this temperature would be ___________ kJ.

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For the reaction 

Fe3O4 (s) + 4H2 (g) → 3Fe (s) + 4H2O (g) 

ΔH° = 151.2 kJ and ΔS° = 169.4 J/K 

The standard free energy change for the reaction of 2.33 moles of Fe3O4(g) at 311 K, 1 atm would be ___________.

This reaction is (reactant, product) ____________ favored under standard conditions at 311 K.

Assume that ΔH° and ΔS° are independent of temperature. 

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