Explanation:
A change that does not cause any change in chemical composition of a substance is known as a physical change.
For example, mass, density, volume etc are all physical changes.
On the other hand, a change that brings change in chemical composition of a substance is known as chemical change.
For example, combustion, toxicity, reactivity etc are all chemical changes.
Hence, following statements are identified as chemical or physical changes as follows.
(a) Oxygen gas supports combustion : Chemical change
(b) Fertilizers help to increase agricultural production : Chemical change
(c) Water boils below 
on top of a mountain : Physical change
(d) Lead is denser than aluminum : Physical change
(e) Uranium is a radioactive element : Chemical change
2Al₂O₃ ----> 4Al + 3O₂
2 moles 3 moles
2 moles of Al₂O₃ ---------- 3 moles of O₂
26,5 moles of <span>Al₂O₃ ------ X
</span>X = (26,5×3)/2
<u>X = 39,75 moles</u> of O₂
:)
Answer:
Ecological Relationships are of two types - Oppositional Relationships and Symbiotic Relationships. Oppositional Relationships are of two types - Predation and Competititon. Symbiotic Relationships are of four types - Mutualism, Commensalism, Amensalism & Parasitism.
Explanation:
<span>Calculate the standard entropy change for the dimerization of NO2: 2NO2(g)→N2O4(g)at 298 K, if
Sâ—¦ â†Hâ—¦f J/K·mol
NO2(g) 240.06 33.18
N2O4(g) 304.29 9.16
Answer in units of J/K·mol
AP Chemistry - DrBob222 Tuesday, October 29, 2013 at 8:53pm
See your other posts below.
AP Chemistry - fg Monday, April 4, 2016 at 4:19pm
dg4354
2242342
1111
AP Chemistry - Eman Monday, April 25, 2016 at 11:19am
-175.8 j/k.mol</span>
