Answer:
Option (A) : Positive
Explanation:
A combustion reaction will always be associated with a change in entropy that is Positive due to the gaseous products released. Hence, there is a large positive entropy change.
Answer:
A
Explanation:
increase in energy - hotter and/or more reactive
decrease in energy - colder and/or less reactive
Since it is going from a liquid to solid it will have a tighter arrangement of particles.
Silicon dioxide is SiO2. Silicon has 4 valence electrons, while each oxygen has 6 valence electrons. This can be shown as
** * *
** O * * Si * * O **
* * **
At points where there is one valence electron, represented by a lone *, the electrons will be 'shared' between the atoms. This will make silicon dioxide appear as
** *--------------- *
** O *--* Si * ------ * O **
*------- * **
, as the lines with no arrows indicate that each electron moves between the atoms, and does not stay with one forever.
