A sample of crushed rock is found to have 4.81 x 10^21 atoms of gold, how many moles of gold are present in this sample? A. 7.99 x 10^-3 moles
B. 1.57 x 10^-1 moles
C. 1.25 x 10^3 moles
D. 2.47 x 10^5 moles

Select the correct answer how does the heat content of the reaction change in the process of photosynthesis when a glucose molecule is formed? ca the value of is negative the value of qis positive the value of a remains constant the value of a decreases the value of equals zero e

Particles vibrate in a rigid structure and do not move relative to their neighbors.

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.