c) Draw the structure of BeH_(2) and show how hybridization takes place in BeH_(2) (7 marks) d) The Law of Conservation of Mass explain why chemical reactions in closed systems don't result in mass loss or gain? (4 marks)

c) The structure of $BeH_{2}$ can be represented as follows:<br /><br />```<br /> H<br /> |<br />Be-H<br /> |<br /> H<br />```<br /><br />In $BeH_{2}$, the beryllium atom (Be) forms two covalent bonds with two hydrogen atoms. To understand how hybridization takes place in $BeH_{2}$, we need to consider the electronic configuration of beryllium.<br /><br />Beryllium has an atomic number of 4, which means it has four electrons. In its ground state, beryllium has two electrons in the 1s orbital and two electrons in the 2s orbital. However, for the formation of covalent bonds with hydrogen atoms, beryllium needs to undergo hybridization.<br /><br />Hybridization involves the mixing of atomic orbitals to form hybrid orbitals that can accommodate electrons. In the case of beryllium, the 2s orbital is involved in hybridization. The two 2s electrons of beryllium are promoted to empty 2p orbitals, resulting in the formation of two sp hybrid orbitals.<br /><br />The sp hybrid orbitals of beryllium are oriented in a linear arrangement, which allows for the formation of two equivalent covalent bonds with hydrogen atoms. Each hydrogen atom forms a covalent bond with one of the sp hybrid orbitals of beryllium, resulting in the formation of $BeH_{2}$.<br /><br />Therefore, in $BeH_{2}$, the beryllium atom undergoes sp hybridization, which allows for the formation of two equivalent covalent bonds with hydrogen atoms.<br /><br />d) The Law of Conservation of Mass states that the total mass of the reactants in a chemical reaction is equal to the total mass of the products. This means that no mass is lost or gained during a chemical reaction.<br /><br />In a closed system, the total mass of the system remains constant. This is because the system is isolated from the surroundings, and no matter can enter or leave the system. Therefore, the total mass of the reactants in a closed system is equal to the total mass of the products.<br /><br />The Law of Conservation of Mass can be explained by the fact that atoms are rearranged during a chemical reaction, but the total number of atoms remains the same. The mass of the reactants is conserved because the mass of each atom is conserved. Atoms are neither created nor destroyed during a chemical reaction; they are simply rearranged to form new compounds.<br /><br />Therefore, the Law of Conservation of Mass explains why chemical reactions in closed systems don't result in mass loss or gain. The total mass of the system remains constant because the mass of the reactants is equal to the mass of the products.