PLEASE HELP ITS RLLY IMPORTANT. Consider the model of Ammonia to the right. Which terms would be used to describe this model? Element, molecule, and/or compound? Explain your reasoning.

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Particles vibrate in a rigid structure and do not move relative to their neighbors.

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?