Most of the chemical energy released when gasoline burns in a car engine is not used to

move the car, but is changed into:

a. electricity

b. heat

c. magnetism

d. sound

When gasoline burns in a car engine, the burning is not used to move the car but is changed into heat.

Option B

Explanation:

Energy can be stored as kinetic and potential energy. As potential energy is the object's energy at rest. When gasoline is filled in car, then the car is attaining potential energy and as the gasoline is a chemical compound, the potential energy will be chemical potential energy.

The chemical potential energy releases energy on breakage of chemical bonds, so depending upon the strength of the bond, the energy will be released. Thus , in this case, the gasoline will burn on starting of the engine and the energy released from the burning of gasoline will be mostly changed to heat energy and some of them will be used for moving the car.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.