Explain why understanding of the terms system and surroundings is important when describing energy changes in a chemical reaction or physical process

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?

27 drag each label to the correct location on the image. a particular exosolar system has five planets in total: a, b, c, d, and e. the table lists the orbital periods of these planets in days. planet orbital period (days) a 600 b 80 c 1,000 d 500 e 100 move each planet to its orbit in the system.

How is an endothermic reaction identified