how many protons , neutrons and electrons ar present in an atom of hafnium , hf , with a mass number of 178?

Which substance is a steroid? cholesterol fatty acid monosaccharide trans fat

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ

What does a complete balanced chemical equation include? a. exothermic coefficients b. endothermic coefficients c. valence electrons d. molar coefficients