Answer: It is called a Crookes Tube, and he used it to discover cathode rays, which were later determined to be electrons.
Answer:
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Answer: Option (A) is the correct answer.
Explanation:
A covalent bond is formed when there occurs sharing of electrons between atoms.
For example, in hydrogen atom there is one electron in its orbit and in a chlorine atom there is 7 valence electron. So, in order to attain stability both hydrogen and chlorine share electrons when they come close to each other.
Whereas except hydrogen and chlorine rest of the given atoms will form ionic bond, that is, bond formed by transfer of electrons.
Thus, we can conclude that a pair of hydrogen and chlorine will form a covalent bond.
Answer:
ΔHrxn = [(1) -1675.5 ( kJ/mole) + (2) 0 ( kJ/mole)] - [(1) -824.3 ( kJ/mole) + (2) 0 ( kJ/mole)]
Explanation:
ΔHrxn = 2ΔHf (Al₂O₃) - ΔHf (Fe₂O₃)
Remember that for pure elements in their standard state of temperature and pressure by definition their standard heats of formation are zero.
ΔHrxn = 2(-1675.7) - (-824.3) kJ/mol
ΔHrxn = 2527 kJ/mol
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