Answer: 
1. Dissolving powder in milk - Chemical
   - It is chemical because the milk has changed on a molecular level
2. Toasting bread - Chemical 
    - It is chemical because adding heat to the bread cooks it, therefore
      changing it on a molecular level
3. Melting cheese - Physical 
    - It is physical because the physical appearance was the only change
4. Slicing apples or bannanas - Physical
    - It is physical because the physical appearance was the only change
5. Frying an egg - Chemical 
    - It is chemical because new particles were formed 
6. Milk souring - Chemical 
    -  It is chemical because it is forming a new product (lactic acid)
Explanation:
Physical Change occurs when the particles of a substance become rearranged, but do not change into different particles.  
Chemical change occurs when a new substance is formed. This process is irreversable.