Place the atoms relative to each other. Place the atom with group number in the center because it has the electronegativity. If atoms have the same group number, place the atom with the period number in the center.

Place the atoms relative to each other. Place the atom with lower group number in the center because it has the lower electronegativity. If atoms have the same group number, place the atom with the higher period number in the center.

Explanation:

Generally, electronegativity increases from left to right within a period (horizontal rows in the periodic table), and decreases from top to bottom within a group (vertical columns).

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.