69.9%
Explanation:
To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound.
Mass percentage = 
x 100
Molar mass of Fe = 55.85g/mol
Molar mass of O = 16g/mol
Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7g/mol
Mass percentage = 
= 69.94% = 69.9%
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Answer 2, because when you add salt to something, it cools faster (ex. When you add salt to an ice chest so that it stays cold) and it takes longer to boil (ex. When you boil salt out of ocean water so that its safe to drink) therefore, the more NaCl in the solution, the more it will exibit these properties
Chemicals that’s and ghebreziqbiher
The substance which has definite composition with definite physical and chemical properties is said to be pure substance. These substances are not separated by the different physical techniques such as filtration, distillation, evaporation etc.
The clear water pumped from a deep aquifer is a pure substance because water is a pure compound which consist of constant single type of atoms or group of atoms and water has specific value of boiling and melting point. Water is also not separated into units or constituents by physical technique.
Hence, clear water pumped from a deep aquifer is a pure substance.
Answer:
Thus,there are 0.2 mole in 8 g of calcium.
