Answer:
Determining how many ozone molecules are lost in the atmosphere.
Explanation:
Answer:
A. a new substance is being produced.
Explanation:
The bubbles most likely indicates that a new substance is being produced by this reaction. In essence, we describe this sort of change as chemical change.
In a chemical change, new substances are usually produced. They are accompanied by the evolution or absorption of energy.
The reaction of Zinc with a strong acid to produce bubbles on the surface of the metal indicates a chemical change and the formation of a new kind of substance.
Take for example, let zinc reacts with hydrocholoric acid, HCl;
Zn + 2HCl → ZnCl₂ + H₂
Since Zn is higher than Hydrogen in the activity series, it will displace it from HCl and liberate hydrogen gas as a product. This will cause the bubbles observed in the reaction.
This is a chemical change and new products have been formed.
B and D are wrong because they are both physical changes.
C is wrong because no information about such is provided by the problem statement.
So, when a piece of zinc metal combines with a strong acid, a new kind of substance is produced.
Given :
An atom of a certain element has 12 protons, 14 neutrons, and 2 valence electrons.
To Find :
The name of this element.
Solution :
We know, element with atomic number ( number of protons ) 12 and valance electrons is Magnesium.
Now, isotope of magnesium of proton with 14 neutrons is Mg-16 .
Therefore, name of element is Mg-16 .
Hence, this is the required solution.