Which of these statements is true of both endothermic and exothermic reactions?

What type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? view available hint(s) what type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? salt bridge disulfide bridge hydrogen bond hydrophobic interaction

Asample of tin (ii) chloride has a mass of 0.49 g. after heating, it has a mass of 0.41 g.  what is the percent by mass of water in the hydrate?   %

An atomic nucleus is composed ofa)protons.b)protons and neutrons.c)protons and electrons.d)protons, neutrons, and electrons.