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Weighing Gases Lesson 8. The electrolysis of water is used to generate 0.250 g of H 2 (g) . If the hydrogen was generated at a rate of 1.500 amps over a period of 4.46625 hours , calculate Avogadro’s number (the number of atoms of H in 1 gram )
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The electrolysis of water is used to generate 0.250 g of H2 (g). If the hydrogen was generated at a rate of 1.500 amps over a period of 4.46625hours, calculate Avogadro’s number (the number of atoms of H in 1 gram) 1 amp is defined as the number of coulombs per second. There are 6.24 x 1018 electronsin a coulomb. It takes 1 electronto make 1 H atom 4.46625 h x 60 min x 60 s x 1.500 coul x 6.24 x 1018 el x 1 at H 1 el s 1 coul 1 h 1 min = 1.505 x 1023 at H = 6.02 x 1023 at H 0.250 g
If you weigh the volumes 1.0 L of CO2 Avogadro’s hypothesis states that equal volumes of gases have the same number of particles. 2.56 g = = = 22 0.116 g 1.0 L of H2 Note that the mass ratio is the same as the molar mass ratio CO2 = 44 g/mole = 22 H2 2.02 g/mole
A volume of an unknown gas weighs 0.563 g. An equal volume of H2 gas weighs 0.01774 g. Calculate the molar mass of the unknown gas. Gas X = 0.563 g = 31.7 x 2.02 g/mole = 64.1 g/mole H2 0.01774g This means the molar mass of gas X is 31.7 x heavier than H2 If the gas is a byproduct of burning coal and causes acid rain, what is the gas? SO2
x 30.06 g/mole = 4.02 g/mole Gas X = 2.365 g = 0.1336 A volume of an unknown gas weighs 2.365g. An equal volume of C2H6 (ethane) gas weighs 17.7g. Calculate the molar mass of the unknown gas. C2H6 17.7 g This means the molar mass of gas X is 0.1336 x C2H6 If the unknown gas is an element, what gas is it? Helium Rock me Avogadro