What simplifying assumptions do we usually make in working problems involving the ionization of a polyprotic acids

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium

How many significant figures are in the following numbers ? a. 0.0002030 b. 2.000 c. 2.008900 d. 145.00

20 look at the clock and the data table below. based on the data and on your knowledge of potential and kinetic energy, what is the best conclusion you can make about potential and kinetic energy? the total amount of energy stays the same. the clock has the most potential energy at point b since it is moving the fastest. there is always more potential energy than kinetic energy. potential energy can never be 0, but you can have 0 kinetic energy.