Which statement is true for most chemical reactions?
An energy change occurs during the breaking and forming of bonds.
The internal energy of the system increases during a reaction.
Energy is released during the formation of reactants.
The enthalpy of the products is higher than the enthalpy of the reactants.

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? a. the wings are analogous structures that evolved differently and do not have a similar internal structure. b. the wings are homologous structures that evolved differently and do not have a similar internal structure. c. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. d. wings of bats are vestigial structures, but the wing structures of birds are not vestigial

What is the molarity of the solution produced when 145 g of nacl is dissolved in sufficient water to prepare 2.75 l of solution?

#20 which type of bond is formed when bases pair in dna? ionic bond covalent bond coordinate bond hydrogen bond