Answer:
It is known that 1 mol of a molecule contains 6.023×1023 6.023 × 10 23 number of molecules. So, 0.25 moles of CO2 C O 2.
"I" symbol means the current goes through the system (imagine the 'I' being a line, like a circuit connecting [power to the device]) "O" symbol means the current does not go through the system. ( the circle is an open circuit, having no power flowing through it
Answer:
32.7 kilograms of aluminium oxide will be produced.
Explanation:

Mass of aluminum = 17.3 kg = 17300 g (1 kg = 1000 g )
Moles of aluminium = 
According to reaction, 2 moles of aluminum gives 1 mole of aluminum oxide,then 640.74 moles of aluminum will give:
of aluminum oxide
Mass of 320.37 moles of aluminum oxides:
320.37 mol × 102 g/mol = 32,677.74 g = 32.67774 kg ≈ 32.7 kg
32.7 kilograms of aluminium oxide will be produced.