The SI unit for the amount of substance present is the mole.
The mole is defined as the amount of substance that has the same amount of particles as there are atoms in 12 grams of carbon-12. Mathematically, the moles of a substance may be computed using:
moles present = mass of substance / molecular mass of substance
Where x represents the number of hours working as a babysitter and y represents the number of hours working as a cashier...
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True, a lunar eclipse occurs when the Moon is between the Sun and Earth