Question

Сожгли 20 г смеси графита с кремнием. ... Рассчитать массу оксида кремния (2),ЕСЛИ МАССОВАЯ ДОЛЯ кремния в смеси 65%?

Answer 1

Calculation of the Mass of Silicon Oxide (SiO2) from the Burning of a Graphite-Silicon Mixture

To calculate the mass of silicon oxide (SiO2) produced from the burning of a graphite-silicon mixture, we need to consider the mass fraction of silicon in the mixture.

Given that the mass fraction of silicon in the mixture is 65%, we can assume that the remaining 35% is graphite.

To calculate the mass of silicon oxide produced, we need to determine the mass of silicon in the mixture and then convert it to the mass of silicon oxide.

Let's assume that the initial mass of the mixture is 20 grams.

1. Calculate the mass of silicon in the mixture: - Mass of silicon = Mass of mixture * Mass fraction of silicon - Mass of silicon = 20 grams * 0.65 - Mass of silicon = 13 grams

2. Calculate the molar mass of silicon oxide (SiO2): - Molar mass of Si = 28.0855 g/mol - Molar mass of O = 15.9994 g/mol - Molar mass of SiO2 = (2 * Molar mass of Si) + (2 * Molar mass of O) - Molar mass of SiO2 = (2 * 28.0855 g/mol) + (2 * 15.9994 g/mol) - Molar mass of SiO2 = 60.0848 g/mol

3. Calculate the number of moles of silicon: - Moles of silicon = Mass of silicon / Molar mass of Si - Moles of silicon = 13 grams / 28.0855 g/mol - Moles of silicon ≈ 0.463 moles

4. Calculate the mass of silicon oxide produced: - Mass of SiO2 = Moles of silicon * Molar mass of SiO2 - Mass of SiO2 = 0.463 moles * 60.0848 g/mol - Mass of SiO2 ≈ 27.8 grams

Therefore, if the mass fraction of silicon in the graphite-silicon mixture is 65% and the initial mass of the mixture is 20 grams, the mass of silicon oxide (SiO2) produced would be approximately 27.8 grams.

Please note that this calculation assumes complete combustion and neglects any other reactions or impurities that may affect the result.