Is this chemistry work correct? - A levelWatch this thread
Mass of crucible and lid (g) 22.71 24.78
Mass of crucible, lid and magnesium (g) 22.81 24.83
Mass of crucible lid and product (g) 22.85 22.86
Mass of magnesium for experiment 1 – 0.1g
Mass of magnesium for experiment 2 – 0.05g
Average mass of magnesium = 0.075g
Analysis of results
1.) Calculate the mass of magnesium that you reacted, the magnesium oxide formed and oxygen that reacted.
2Mg (s) + O2 (g) 2MgO (s)
Mass of magnesium reacted = 0.075g
Number of moles of magnesium = Mass / Molar mass
= 0.075/24.3 = 0.0031 mol
Number of moles of oxygen reacted = 0.0031/2 = 0.0015mol
So, as you have correctly worked out, 0.0015 moles of oxygen were formed.
Mass of one mole of O2 = 16 X 2 = 32 g
So the mass of oxygen that reacted on average in EACH of your 2 experiments = 0.0015 X 32 = 0.048g = 48 mg
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