When a substance changes into a different substance, you are observing its chemical properties.
In a physical change, the substance must <em>not </em>change into a different substance.
The physical and chemical properties of a substance do <em>not</em> change.
Answer:
You didn't give any options/statements, so I'm just going to give you context on what catalysts does. Catalysts decrease the activation energy needed, allowing more particles for successful reactions.
I know my colleague tried doing an experiment by using hydrogen peroxide as a catalyst and seeing how rates of reactions were affected. It ended up with a stain on our chemistry lab and him re-doing his entire lab.
Plate tectonics is the theory that Earth's crust is composed of many plates that are moving slowly over time.
Your answer is D. :)
Answer : The correct option is, (B) no double bonds.
Explanation :
Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.
In the Lewis-dot structure the valance electrons are shown by 'dot'.
As we are given that the structure of the compound containing 1 carbon and 4 chlorine atoms.
Thus, the molecule is, 
As we know that carbon has '4' valence electrons and chlorine has '7' valence electrons.
Therefore, the total number of valence electrons in
= 4 + 4(7) = 32
According to Lewis-dot structure, there are 8 number of bonding electrons and 24 number of non-bonding electrons.
From the Lewis-dot structure we conclude that there are 4 single bonds are surrounding the central atom of this ion there is no double or triple bonds are present.
Hence, the correct option is, (B) no double bonds.
The statement which describes how NO2- reacts in this equilibrium:
<span>H2SO3(aq) + NO2-(aq) HSO3-(aq) + HNO2(aq
is the second option - </span><span>B. as a Brønsted-Lowry base by accepting a proton.
</span>This is because bases take proton H+ in order to become HNO2.