A. <span>Standing is health-enhancing because it uses energy.
Because standing can burn a lot of calories.</span>
Answer:
The sum of positive and negative charges in a unit of Al2O3 equals zero.
Aluminium has a charge of +3 while Oxygen has a charge of -2 on each ion.
Al203 has 2 Al atoms and 3 O atoms.
Charge on Al2O3 = 2(charge on Al ion) + 3(charge on O ion)
= 2(3) + 3(-2)
= 6 - 6
= 0
Explanation:
Aluminium has 3 electrons in the outermost shell and has the tendency to lose those 3 electrons to form a positive ion and have a complete outermost shell.
Whereas, Oxygen has 6 electrons in the outermost and has the tendency to accept two more electrons to form a negative ion and have a complete outermost shell.
Answer:
<em>The comoving distance and the proper distance scale</em>
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Explanation:
The comoving distance scale removes the effects of the expansion of the universe, which leaves us with a distance that does not change in time due to the expansion of space (since space is constantly expanding). The comoving distance and proper distance are defined to be equal at the present time; therefore, the ratio of proper distance to comoving distance now is 1. The scale factor is sometimes not equal to 1. The distance between masses in the universe may change due to other, local factors like the motion of a galaxy within a cluster. Finally, we note that the expansion of the Universe results in the proper distance changing, but the comoving distance is unchanged by an expanding universe.
