Why is it a sefety procedure to tie back long hair in a laboratory?

Does the energy in a solid increase or decrease when changing to a liquid?

Which of the following statements about hybrid orbitals is or are true? choose all that apply. choose all that apply. under sp2 hybridization, the large lobes point to the vertices of an equilateral triangle. after an atom undergoes sp hybridization there is one unhybridized p orbital on the atom. the angle between the large lobes of sp3 hybrids is 109.5∘

How do you know when a chemical reaction has occurred