Which one is an ionic compound?
CO₂
HF
CuCl₂
HI
CuFe

Which statement about the stamps is correct?

Design techniques and materials that reduce the negative environmental impact of a structure are referred to as

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.