What is changed when matter undergoes a physical change? give an example to explain your answer . : )

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?

How many moles of no2 will form when 3.3 moles of cu are reacted with excess hno3?

Which factor is likely to impact the possible number of compounds? presence of unlimited number of elements in the periodic table the inability of atoms to align perfectly with other atoms the ability of all elements to react with every other element all elements being equally reactive