Energy is required to change the phase of a substance, such as the energy to break the bonds between molecules in a block of ice so it may melt.
During a phase change energy my be added or subtracted from a system, but the temperature will not change. The temperature will change only when the phase change has completed. No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a phase change). For example, consider water dripping from icicles melting on a roof warmed by the Sun. Conversely, water freezes in an ice tray cooled by lower-temperature surroundings. Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart so that the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature.
Answer:
It might cave in on itself or collapse because of the change in pressure.
Answer:
Explanation:
You can calculate the entropy change of a reaction by using the standard molar entropies of reactants and products.
The formula is
The equation for the reaction is
C₂H₄(g) + 3O₂(g) ⟶ 2CO₂(g) + 2H₂O(ℓ)
ΔS°/J·K⁻¹mol⁻¹ 219.5 205.0 213.6 69.9
Answer:
B) Electrons are located in the cloud-like areas around the nucleus.
Explanation:
The quantum mechanical model of the atom does not consider the path through which an electron travels. It rather estimates the probability of where electrons can be found at each energy level.
The region of maximum probability of where an electron is located is sometimes called an electron cloud or orbital. Each orbital of an atom and the electrons accomodated are described completely by a set of four quantum numbers.
16. FALSE
17. TRUE
18. FALSE
19. TRUE
20. TRUE
