You are conducting a calorimetry experiment using a calorimeter with 500mL of water in its outer chamber to determine the enthalpy of reaction of a chemical reaction. The initial temperature of the water is 25°C. After the reaction, the temperature of the water is 62.8°C. Disregarding any heat loss to the walls of the container, calculate the ΔHr0. The specific heat of water is 4.18J/(g•K).

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.