Answer:
45) the answer is C.
46) The calculation of quantities in chemical reaction is called Stoichiometry
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47) The phase changed from solid to gas so I think the answer is A.
48) The phase changed from solid to gas as well so I think that the answer is A again.
49) Applying the formula n = m/M, we have n = 1.5 moles, therefore the answer is D.
50) C2H4 + 3O2 -> 2H2O + 2CO2
The answer is C.
51) The answer is C.
52) 2NaHCO3 + CaCl2 -> CaCO3 + H2O + 2NaCl + CO2
Hopefully I got all of them correct.
