Steel joints often separate sections of concrete bridges. why? a. an increase in kinetic energy can cause the bridge to contract. b. a decrease in temperature can cause the materials to expand. c. thermal expansion can cause the materials to shrink. d. thermal expansion can cause the concrete to expand and crack.

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

Llama have 74 chromosomes how many chromosomes will they be found in their gametes explain how you know

Air can be considered a mixture. which statement does not explain why?