What happens to elements when they gain energy

Initially, the balloon had 3.0 liters of gas at a pressure of 400 kpa and was at a temperature of 294 k. if the balloon is cooled to 277 k and its volume decreased to 1 l, what will the new pressure in the balloon be?

Apiece of metal with a length of 1.42 cm was measured using four different instruments. which of the following measurements is the most accurate?

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.