physical
chemical
nuclear
A physical change occurs when a substance changes phase.
For example, boiling pure water (H₂O) is physical change of substance (from liquid to gaseous state). In physical change, the bonds between oxygen and hydrogen can not be separated.
Sublimation of iodine (from solid to gas state) is also physical change.
Physical property can be observed and measured without any changes in molecular composition. The same substance is present before and after the change.
A physical change occurs when a substance changes phase. In this process, a substance may change from one state of matter to another but its foundational substance remains the same.
A physical change takes place when a substance alters its phase. This means that it shifts from one state of matter (solid, liquid, gas) to another. It's crucial to remember that although the physical characteristics of the substance may change, its substance does not. Let's take an example of water, it can exist as solid (ice), liquid (water), and gas (steam) but in all these states it remains H2O. Therefore, when a substance changes phase, it undergoes a physical change, not a chemical or a nuclear change.
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Which statement describes this change?
(1) It is endothermic, and entropy decreases.
(2) It is endothermic, and entropy increases.
(3) It is exothermic, and entropy decreases.
(4) It is exothermic, and entropy increases.
Answer: (2) It is endothermic, and entropy increases.
Explanation: Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.
Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.
In the given reaction:
The energy is absorbed by the reactants and thus it is endothermic and the solid reactants are converting to gaseous products, thus the entropy increases.
false?
The time taken for the croissant to hit you on the head assuming you are 1.5 m tall is 7.73 s
Considering the question given above, your height was not stated.
Thus, the height of the Eiffel Tower to your head will be:
Total height of tower = 300.5 m
Your assumed height = 1.5 m
Height (h) = 300.5 – 1.5
Finally, we shall determine the time taken for the croissant to hit you on the head.
Height (h) = 299 m
Acceleration due to gravity (g) = 10 m/s²
H = ½gt²
299 = ½ × 10 × t²
299 = 5 × t²
Divide both side by 5
Take the square root of both side
Therefore, the time taken for the croissant to hit you on the head assuming you are 1.5 m tall is 7.73 s
Learn more: brainly.com/question/19168584