1. rancidification fixation of water is CHEMICAL CHANGE
2. Tearing of paper is PHYSICAL CHANGE
3. Rusting if iron is CHEMICAL CHANGE
4. Electrolysis of water is CHEMICAL CHANGE
The rate of dissolution of a solid solute into the solution decreases when you stop stirring it. Generally, stirring increases the dissolution rate of a solid into a solution. An example is coffee with sugar, the sugar dissolves faster when stirred versus when left to dissolve on its own.
Answer:
Part A: 36 MBq; Part B: 18 MBq
Explanation:
The half-life is the time it takes for half the substance to disappear.
The activity decreases by half every half-life
A =Ao(½)^n, where n is the number of half-lives.
Part A
3.0 da = 1 half-life
A = Ao(½) = ½ × 72 MBq = 36 MBq
Part B
6.0 da = 2 half-lives
A = Ao(½)^2 = ¼ × 72 MBq = 18 MBq
They are atoms. a molecule is made up of atoms.
