The mass percent composition of aluminum is 52.9% in aluminum oxide.
Mass of the aluminum = 3.53 g
Mass of the aluminum oxide = 6.67 g.
The mass percent of a substance is the mass of the substance divided by the mass of the compound into 100.
Aluminum reacts with oxygen to form aluminum oxide.
The overall balanced equation for the reaction is,


The mass percent composition of aluminum in the aluminum oxide is,



= 52.9 %
Therefore, the mass percent composition of aluminum is 52.9% in aluminum oxide.
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Answer:
Catastrophic theories
Explanation:
The theory of catastrophe is a collection of methods used to analyze and describe the ways in which a system can experience sudden significant behavioral changes when one or more of the variables that govern it are continuously modified.
Georges Louis de Buffon suggested in 1745 the first destructive theory — that a comet pulled material from the Sun to form the planets.
Therefore the answer is -
Catastrophic theories
Answer:
A plane mirror is a mirror with a flat (planar) reflective surface. For light rays striking a plane mirror, the angle of reflection equals the angle of incidence. The angle of the incidence is the angle between the incident ray and the surface normal (an imaginary line perpendicular to the surface).
It really depends on what the bulb is being used for, since efficiency means how much of the output is USEFUL.
If the bulb is being used for light in a dark room, then it produces (8.2% x 21W) = 1.72 joules per second of light energy.
If the bulb is being used to keep a hamster cage or a fish tank warm, then the 8.2% is the useful part, and the light is the other (91.8% x 21W) = 19.28 joules per second.