Define physical change and give an example

Which orbitals form a pi bond? a.the s orbital and three p orbitals b.the s orbital and two p orbitals c.overlapping p orbitals d.overlapping hybrid orbitals

If 1.63 times 10 negative 4 of helium dissolves in 100.0g of water, what is the concentration in parts per million

An observation that requires measurement is called quantitative observable or qualitative