Fix ur transition, it sounds choppy
Because it is extremely hot.
Answer:
A mixture is just a combination of things, like air (made up of different but distinct gasses), or toothpaste, where compounds are physically mixed together but stay fundamentally what they started as. If there is a chemical change, like hydrogen and chlorine gas reacting to form hydrochloride acid, then it is known as a new compound.
Question 12 is Noble gas and question 13 is actinide-series element.
Decay is a type of degradation reaction and thus is considered a first order reaction. thus the formula goes like this.
rate constant= 0.693/half life
so here...
rate constant= 0.693/1620 year^-1