Answer: remains constant.
Justification:
1) The phase changes are:
i) Boiling: pass from liquid to gas (absorbs heat energy)
ii) Condensation: pass from gas to liquid (release heat energy)
iii) Melting: pass from solid to liquid (absorb heat energy)
iv) Freezing: pass from liquid to solid (release heat energy)
v) Sublimation: pass from solid to gas (absorbs heat energy)
vii) Deposition: pass from gas to solid (release heat energy)
2) When a phase change occurs, whichever it is, the heat energy related with the process, either absortion or release, is used, to overcome the intermolecular forces (in the case of heat energy absortion) or to create stronger intermolecular forces (in the case of heat energy release).
Because of that, the heat energy exchange does not change the temperature of the substance.
Answer:
ex.1
1.The water in the test tube expands as it is heated. There is only one direction to expand in, the glass tube. This glass tube is narrow so that a small change in volume will result in a considerable change in height; your signal is amplified. This is the same phenomenon as in thermometers with a glass bulb on the lower end.
2. there will be a thermal expansion will happened.
When NH3 is dissolved in water, it dissociates partially producing NH4+ ions and OH- ions. It has an equation:
NH3 + H2O → NH4+ + OH-
<span>We use the Kb expression to determine the [OH-] concentration,
</span>
<span>Kb = [NH4+] [OH-] /* [NH3] </span>
We can write NH4+ as OH- since they are of equal ratio.
<span>(1.76*10^-5) = [OH-]² / 0.188
</span><span>[OH-]² = 3.3088*10^-6 </span>
<span>[OH-] = 1.819*10^-3 </span>
We calculate for H+ concentration as follows:
<span>[H+] [OH-] = 10^-14 </span>
<span>[H+] = 10^-14 / [OH-] </span>
<span>[H+] = 10^-14 / (1.819*10^-3) </span>
<span>[H+] = 5.50*10^-12 </span>
<span>pH = -log [H+] </span>
<span>pH = -log (5.5*10^-12) </span>
<span>pH = 11.26</span>
Fossils are great for providing evidence for an evolutionary change! Scientists can see how long life has existed on Earth by studying fossil records. Any living organism that is preserved, is considered a fossil, including plants! Fossils take 10,000 years to be formed, showing that, yes, fossil evidence supports that these cycles of evolution take quite a long time.
Hope this helps!
-Moiselle
