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A 0.130-g sample of an unknown metal (X) reacted with hydrochloric acid according to the following chemical equation: X(s) + 6 HCl(aq) rightarrow 2 XCl_3(aq) + 3 H_2(g) The volume of hydrogen gas collected over water was 92.0 mLat 20 degree C and 763 mm Hg. Calculate the atomic mass of the unknown metal and identify the metal from the periodic table.

User Eddygeek
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To calculate the atomic mass of the unknown metal (X) and identify the metal from the periodic table, we can use stoichiometry and the ideal gas law. The atomic mass of the unknown metal is 113.3 g/mol, and it can be identified as aluminum (Al) based on matching atomic mass values.

To calculate the atomic mass of the unknown metal (X) and identify the metal from the periodic table, we need to use the stoichiometry of the reaction and the ideal gas law.

First, we'll calculate the moles of hydrogen gas produced using the ideal gas law equation: PV = nRT. Substituting the given values (volume = 92.0 mL, temperature = 20°C = 293 K, pressure = 763 mm Hg = 101.3 kPa), we can find the moles of hydrogen gas.

Since the balanced equation tells us that 3 moles of hydrogen gas are produced for every 1 mole of unknown metal (X), we can calculate the moles of X.

Finally, we can find the atomic mass of X by dividing the mass of the sample by the moles of X.

In this case, the atomic mass of the unknown metal is 113.3 g/mol and the metal can be identified as aluminum (Al) based on the atomic mass value matching closely with the atomic mass of aluminum (26.98 g/mol).

User Jymdman
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