What does below chemistry rebus means?

Where do you go to learn how to make ice cream?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

I always drive my customer away.

Who am I?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

Can you fill the blank with the correct number?

6 30 870 756030 _____

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

Give it food and it will live; give it water and it will die.

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?