Why the atomic mass of the copper is not exactly equal to 64

Are scientific theories all proven facts?

A sealed vessel containing sulfur dioxide and nitrogen has a total pressure of 520 Torr and partial pressures of 266 Torr nitrogen. What is the partial pressure of sulfur dioxide in Torr?

What maximum fraction of the air in the room could be displaced by the gaseous nitrogen?

Which molecule could form a coordinate covalent bond with a proton (h) ?

When zinc is exposed to air, zinc oxide is produce. What happens in this reaction

A 126-gram sample of titanium metal is heated from 20.0°C to 45.4°C while absorbing 1.68 kJ of heat. What is the specific heat of titanium?

What pressure (in atm) will a sample of o2 gas occupy at 100.0 ml, if o2 has a volume of 25.00 ml at 2.0 atm?

What happens when francium and nitrogen are mixed

Which type of chemical reaction occurs in 2KClO3 Right arrow. 2KCl + 3O2

An electrochemical cell is constructed using two half-cells: Al (s) in Al (NO2) 3 (aq) and Cu (s) in Cu (NO3) 2 (aq). The two half cells are connected by a KNO3 salt bridge and two copper wires from the electrodes to a voltmeter.