17) 8.4 / 20 x 100
18) 20 . 0.5150
19) 6,50% because (as you said) the law of definite proportions states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
Carbon atoms are saturated with (surrounded by) Hydrogen atoms
Answer:
Please see Explanation and Attachment (Heating Curve for Water)
Explanation:
Energy change associated with phase change in substances is either endothermic (energy added to system) or exothermic (energy removed from system). Condensation is but one term in six (6) describing phase change occurring when energy change is involved. The following table, in general, summarizes the related effects of energy change as applied to phase change.
Process Phase Change Energy Change*
Condensation gas => liquid Exothermic
Evaporation liquid => gas Endothermic
Freezing liquid => solid Exothermic
Melting solid => liquid Endothermic
Sublimation solid => gas Endothermic
Deposition gas => solid Exothermic
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* Energy Change terms:
Endothermic => Addition of heat energy
Exothermic => Removal of heat energy
Answer:
part a: How much of the isotope will you have left after 10 years?
part b: How much of the isotope will you have left after 20 years?
part c: How many half-lives will occur in 40 years?