Answer:
They went from atoms to oxygen molecule.
Explanation:
I'm not sure if this is the answer your teacher is looking for, but in simple terms you had 2 oxygen atoms. Together they make an oxygen molecule, which is the stuff we breathe.
Answer:
Pressure will increase by the direct ratio of the volume change. Therefore, since volume changes from 145 to 80, pressure will go up by the ratio change 145÷80 times the original pressure 125 kPa. Sure, you can use the more complicated gas law equation PV = nRT but we are only varying volume so the question boils down to the change in one simple variable.
Putting them together we have: 145÷80 x 125 = 226.5625 or just 226 kPa since the accuracy of the figures and the equation are not great.
A catalyst is a chemical substance that hastens the chemical reaction. This does not participates in the creating the product(s) but allows it to be formed easily. With this, it is now known that the rate of the reaction becomes relatively higher compared to the uncatalyzed reactions.
Therefore, the answer to this item is the rate of the reaction becomes faster.
Silicon generally forms at least polar covalent bonds, like carbon, as befits its status as a Gropu 4A nonmetal. The only obvious exception I can think of is SiC, which despite the similarity you might expect to graphite or diamond does, I think, have significant ionic or metallic character to its bonding in the solid state.
Answer:
D. A is a metal from group 2, and X is a nonmetal from group 7