ITUS PIOLO 54. An unknown isotope has a half-life of 20 seconds. How much of your original sample will remain after 1 minute if
you started with 1500 grams of the isotope? I
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Consider the nuclear equation below. 239 > x + 4 he 94 2 what is x? 1.235 cm 96 2.243 u 92 3.235 u 92 4.243 cm 96

What pressure will be exerted by 0.675 moles of a gas at 25*c if it is in a 0.750-l container?

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.