What is the energy change if 210 g of nahco3 decomposes in the following reaction?

2nahco3 (s) yields na2co3 (s) + h2o (l) +co2 (g) delta h = 85 kj

answers -

53 kj of energy is released by the reaction.

106 kj of energy is absorbed by the reaction.

159 kj of energy is released by the reaction.

212 kj of energy is absorbed by the reaction.

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

Which of the following nuclei would be the least stable a 2 protons, 2 neutrons b 1 proton 1 neutron c 1 proton 3 neutrons d 1 proton 2 neutrons

3.09 lab: reaction of metals 1 which combinations of substances resulted in a chemical change? for each metal that participated in a chemical change, write the type of metal it is, based on your examination of the periodic table. were there any metallic compounds that did not react with either the acid or the base? write the type of metal, based on your examination of the periodic table. make a general statement about the reactivity of the metals in this experiment.