If the density of an individual crystal of polyethylene (PE) is 0.983 g/cm3 and the density of totally amorphous polyethylene (PE) is 0.869 g/cm3, determine the fraction of crystallinity of a PE sample having density of 0.950 g/cm3 at the same temperature, (a) based on mass fraction, and (b) based on volume fraction.

What type of electromagnetic radiation has a shorter wavelength than blue light

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks. energy was destroyed inside the blocks. energy was absorbed into the blocks from outside the system. energy was transferred from the warmer block to the cooler block.

How does the atmosphere to make earth livable? check all that apply. causes the seasons contains oxygen provides warmth creates important nutrients blocks harmful energy from the sun plz like !