Answer:
Chemical changes
Explanation:
a)Burning a piece of charcoal - chemical change
b) Heating copper (ii) carbonate strongly - chemical change
c) Heating Zinc oxide strongly - chemical change
The given types of reaction indicates chemical changes. A chemical change is one in which a new kind of matter is formed. It is always accompanied by energy changes. The process is not easily reversible and hence, it is a permanent procedure.
Burning of charcoal produces a new kind of produces in the combustion process.
Both heating of copper(ii)carbonate strongly and zinc oxide will lead to a decomposition reaction in which new compounds are formed.
A. helium, neon and argon, because they are in the same group or column
C = 12 g
O = 16 g
H = 1 g
<h3>Further explanation
</h3>
Conservation of mass stated that
<em>In a closed system, the masses before and after the reaction are the same
</em>
we can calculate the mass of each atom in the compound :
O in O₂ :
mass O₂ = 32
mass O = 32 : 2 = 16 g
H in H₂O
mass H₂O = 18
mass 2.H + mass O = 18
mass 2.H + 16 = 18
mass 2.H=2
mass H = 1 g
C in CH₄
mass CH₄ = 16
mass C + mass 4.H = 16
mass C + 4.1=16
mass C = 12 g
or we can use formula :
Mass of a single C :
This is a difficult task because zinc is much more active than copper and could hardly be passivated. ... The sur- face immediately turns white (the color of copper(I) iodide) and the yellow-brown color of iodine quickly fades. Rinse the coin with water, brighten it with polish and cloth and begin the whole process again.N
Ca +2
At -1
In +3
Sr +2
Ra +2
Fr +1
Ba +2
As -3
