Calculate the heat of reaction ΔH for the following reaction:
2NH3(g)→N2(g)+ 3H2(g)

Which traits do human embryos have that link them to a common ancestor with fish and reptiles? a. scales and tail b. gill slits and scales c. tail and gill slits d. hair and tail

Select the correct answer. which statement is true about a polarized object? o a. it gains electrons and becomes negatively charged. ob. it gains protons and becomes positively charged. oc. the number of positive and negative charges can be the same. od. it has to be a metal. o e. there is no change in the distribution of the charge in the object. reset next what

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.