A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds. Elements: are pure substances made up of only l type of atom. Atoms of the same element are identical in properties.
Answer:
I. Increasing pressure will allow more frequent successful collision between particles due to the particles being closer together.
II. Rate of reaction increases due to more products being made; as increased pressure favours the exothermic side of the equilibrium.
III. Increasing temperature provides particles lots of (Kinetic) energy, for more frequent successful collision due to the particles moving at a faster rate than before. However, favouring the endothermic side of the equilibrium due to lots of energy required to break and form new bonds.
IV. Rate of reaction increases due to increase temperature favouring both directions of the equilibrium - causing products to form faster.
Hope this helps!
They occur between polar molecules
