What does below chemistry rebus means?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

What does this rebus photo means?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

A fresher was sitting in an interview. The interviewer said, "This is the last question of your interview. Tell me the accurate position of the centre of this table where your resume is kept."

How can he answer this question? What will you have answered to such a question?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Which number should replace the question mark?

At a Society election for president, precisely 963 votes were cast.
There is a total of 4 candidates that participate in the election.

The winning candidate exceeds the opponents by 53, 79 and 105 votes.

How many votes do each candidate gets?