Which substance in the table below has the strongest intermolecular forces

In which situation can a mixture always be called a solution

How are isotopes of the same chemical element alike? how are they different?

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.