Answer : Chemical energy to thermal energy
Explanation : When the welding torch uses the acetylene fuel for producing flame it is using the chemical acetylene to generate energy in form of light, after the flame is produced the fuel is used for melting a metal which is utilizing the thermal energy. So the ultimate final product is generated from chemical to thermal and so the energy transformation is from chemical energy to thermal energy.
Answer:
Beta emission
Explanation:
In beta emission, a neutron is converted into a proton thereby emitting an electron and a neutrino. A neutrino is a particle that serves to balance the spins.
When a nucleus undergoes beta emission, the mass number of the parent and daughter nuclei remain the same while the atomic number of the daughter nucleus is greater than that of its parent by one unit.
Hence, in beta emission, the daughter nucleus is found one pace to the right of the parent in the periodic table.
I think thee correct answer from the choices listed above is option D. <span>When a physical change in a sample occurs, composition of the sample does not change. It stays the same. Also, the properties of the sample will still be the same. Hope this answers the question.</span>
Answer:- The formula 
tells us that one formula unit of this compound is composed of one calcium atom, two nitrogen atoms, and six oxygen atoms.
Explanations:- Subscripts tell us about the number of atoms of the element for which they are used. For example, here the subscript of Ca is one, it means there is one calcium atom in the given one formula unit.
When we have subscripts inside and outside the parenthesis then they are multiplied and the outside subscript is considered for all the atoms present inside the parenthesis.
Here, for the given chemical formula, the subscript of N is 1 and the subscript present outside is 2. So, 1 x 2 = 2 and for oxygen, 3 x 2 = 6
So, we have one calcium atom, two nitrogen atoms and six oxygen atoms for one formula unit of given compound.
