Actually, I strongly believe it is a switch.
Answer:
option A= Physical change
Explanation:
physical change:
" It is a change in which no new substance is formed"
Breaking of object like glass is the example of physical change because it is not change into another object. It effect the form of object but can not change the chemical composition.
Chemical changes:
" it is a change in which one substance is converted into new product through chemical reaction".
During the chemical changes the types and the number of atom remain same but their arrangement changed.
for example: burning of wood, baking of cake, digesting food, resting of iron etc.
Physical reaction:
" physical reaction occur during the molecular rearrangement. There is no chemical change occur"
In this type of changes no bonds are break to form new bonds, for example boiling point.
Chemical reaction:
" chemical reaction occur when molecules are chemically react with each others and bonds formation and breaking is also occur"
Answer:i believe you are to decompose the formula (i think)
In this question we have given the gram of water and we know that 1 mole of water = 18 gram of water and 27 g of water contain 1.5 g of water 27 / 18 = 1.5 g
As we know that avogandro'S no is equal 6.022*1023
1.5g * 6.022*1023 = 9.0 * 1023 molecules present in each 27 g of water.
I hope you will understand better now if you like then comment below and tell me. Best of luck.