How is an endothermic reaction identified?

Which type of orbits are found in the principal energy level n = 2 a - s b - s, f c - s, d d - s, p e - s, p, d

In a chemical reaction, the final amount of the products is determined by the a. universal gas law b. law of definite proportions c. air pressure d. temperature e. none of the above me

Achemical reaction is done in the setup shown , resulting in a change of mass. what will happen if the same reaction is done in a sealed container that is placed on the electronic balance?