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These physical changes could be classified based on their energy requirements: endothermic or exothermic. Endothermic reaction need to absorb energy, while exothermic reaction need to release the energy in order to achieve spontaneous reactions.
Exothermic: Condensation, Freezing, Deposition
Endothermic: Sublimation, Evaporation, Melting
Mr. Roentgen's x-rays allowed scientists to measure the size of the atom. The x-rays were small enough to discern the atomic clouds. This was done by scattering x-rays from atoms and measuring their size just as Rutherford had done earlier by hitting atoms with other nuclei starting with alpha particles.
Answer:
Explanation:
The density of an object is given by
where
m is the mass of the object
V is its volume
In this problem,
m = 42 kg
V = 22 m^3
Substituting into the equation, we find the object's density:
<span>the heated filament will react with the oxygen in the air but now with the argon, which is a noble gas and hardly ever reacts.</span>
