Achange in means that a chemical reaction has occurred. a) the energy and mass b) the kinds of atoms involved c) the properties and identity of the reacting substances d) the energy and kinds of atoms of the reacting substances

 c) the properties and identity of the reacting substances

Explanation: A chemical change is one in which the chemical composition of the atoms change. Every change follows law of conservation of mass and energy i.e. the mass and energy of the system remains conserved.

The above equation represents a chemical change in which hydrogen  and oxygen in gaseous form react to form water in liquid state. In this reaction, Oxygen is a supporter of combustion, hydrogen does not support combustion, whereas water is used to prevent combustion.

b. acid is the correct answer @jayxboof all social media

acid : acids are those which accepts an electron-pairs.

base : bases are those which donates ab electron-pairs.

alkali : it is a base that dissolves in water. it is basically a base and the ph greater than 7.

hydroxide ion : it is a poly-atomic ion which is negatively charged.

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm