Answer:all
Explanation:
Because a reaction does not starts by itself unless some force is applied
Answer:
56°
Explanation:
First calculate 

The interplanar spacing can be calculated from:

The diffraction angle is determined from:

Solve for 

The diffraction angle is:

Answer:
RbI<RbBr<RbCl<RbF
Explanation:
As stated in the question, the latice energy depends on the relative size of the ions. When the action size is constant as in the question, the lattice energy now depends on the relative of the anions. The order of increase in ionic sizes among the halide ions is fluoride<Chloride<Bromide<Iodide. This order of increasing size means that the lattice energy will decrease accordingly as shown in the answer.
The amount or disorder in a chemical system or system is measured by it's Entropy. Entropy is the simply the measure of the amount of disorder or lack of structure present within a system.