NaF is not covalent, but ionic, as Na and F are on opposite sides of the periodic table.
Because she was treated like a ranch hand and expected to work on the farm and she wasn't really given any freedoms for her first marriage and her second marriage started off good but her husband later became abusive beating her and calling her names. Neither of these marriages she could really leave because she wouldn't have anywhere to go and once she did then she left.
Hi I only got number 1&3 hope that helps :)
1: A system is collection of two or more objects but how ca we define an object suppose if we talk about a tennis ball its an object but at atomic level we can say it is a system because it is made of millions of atoms and each atom can be considered as an object
3: The internal energy of a system is identified with the random, disordered motion of molecules; the total (internal) energy in a system includes potential and kinetic energy. ... It is the sum of all the microscopic energies such as: translational kinetic energy. vibrational and rotational kinetic energy
