Answer:
no H2O molecules are produced:)
Explanation:
Answer: The reaction is exothermic
The
value is negative.
Heat is a product.
Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and
for the reaction comes out to be positive.
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and
for the reaction comes out to be negative.
The substances which are written on the left side of the arrow are reactants and the substances which are written on the right side of the arrow are products. Thus heat is a product.
Answer:
Option C. 1
Explanation:
Step 1:
Determination of the Neutron of both isotopes. This is illustrated below.
For isotope y xA:
Mass number = y
Atomic number = x
Neutron =..?
Atomic number = proton number = x
Mass number = Proton + Neutron
y = x + Neutron
Rearrange
Neutron = y – x
For isotope (y + 1) xA:
Mass number = y + 1
Atomic number = x
Neutron =.?
Atomic number = proton number = x
Mass number = Proton + Neutron
y + 1 = x + Neutron
Rearrange
Neutron = y + 1 – x
Step 2:
Determination of the difference between the neutron number of both isotopes. This is illustrated below:
For isotope y xA:
Neutron number = y – x
For isotope (y + 1) xA:
Neutron number = y + 1 – x
Difference in neutron number
=> (y + 1 – x) – (y – x)
=> y + 1 – x – y + x
Rearrange
=> y – y + 1 – x + x
=> 1
Therefore, the difference in the neutron number of both isotopes is 1
A, O2 has to be a reactant for combustion to burn