An example of the hertzsprung-russell diagram is shown above. using this diagram, what can you say about white dwarfs? (hint: notice that the temperature on the x-axis is hotter on the left and cooler on the right.) a. they are very bright and hot. b. they are very bright, but relatively cool. c. they are relatively dim, but very hot. d. they are relatively dim and cool.

Agas mixture with a total pressure of 745 mmhg contains each of the following gases at the indicated partial pressures: co2, 245 mmhg ; ar, 119 mmhg ; and o2, 163 mmhg . the mixture also contains helium gas. part a what is the partial pressure of the helium gas? phe p h e = nothing mmhg request answer part b what mass of helium gas is present in a 10.2-l sample of this mixture at 283 k ? m m = nothing g request answer

What element breaks down into yttrium-90?

Which statement describes both homogeneous mixtures and heterogeneous mixtures?