Ca3(PO4)2 is the correct formula.
Response: The rate constant at 525 K is, 
Rationale:
Based on the Arrhenius equation,
or,
![\log (\frac{K_2}{K_1})=\frac{Ea}{2.303\times R}[\frac{1}{T_1}-\frac{1}{T_2}]](https://tex.z-dn.net/?f=%5Clog%20%28%5Cfrac%7BK_2%7D%7BK_1%7D%29%3D%5Cfrac%7BEa%7D%7B2.303%5Ctimes%20R%7D%5B%5Cfrac%7B1%7D%7BT_1%7D-%5Cfrac%7B1%7D%7BT_2%7D%5D)
where,
= rate constant when 
= 
= rate constant when 
=?
= activation energy for the process = 
R = gas constant = 8.314 J/mole.K
= initial temperature = 701 K
= final temperature = 525 K
Substituting the provided values into this formula yields:
![\log (\frac{K_2}{2.57M^{-1}s^{-1}})=\frac{1.5\times 10^5J/mol}{2.303\times 8.314J/mole.K}[\frac{1}{701K}-\frac{1}{525K}]](https://tex.z-dn.net/?f=%5Clog%20%28%5Cfrac%7BK_2%7D%7B2.57M%5E%7B-1%7Ds%5E%7B-1%7D%7D%29%3D%5Cfrac%7B1.5%5Ctimes%2010%5E5J%2Fmol%7D%7B2.303%5Ctimes%208.314J%2Fmole.K%7D%5B%5Cfrac%7B1%7D%7B701K%7D-%5Cfrac%7B1%7D%7B525K%7D%5D)
Thus, the rate constant at 525 K is,
Fossils are primarily found in sedimentary rocks, which are formed from the buildup of sediments such as sand or mud. Weathering factors, including wind, erode sediments from land and deposit them into bodies of water. Consequently, fossils of marine creatures are more prevalent than those of terrestrial creatures. Land-dwelling animals and plants that have been preserved are generally located in sediments within serene lakes, rivers, and estuaries.
The chances of any living organism turning into a fossil are relatively low. The transition from a living organic entity to a fossilized state is a long and roundabout process. Fossilization typically occurs under optimal conditions, where an animal or plant dies and quickly gets buried with moist sediment. This quick covering prevents consumption by other organisms or the natural decomposition caused by exposure to oxygen and bacteria. Soft tissues of plants and animals decompose much faster than their hard structures. Thus, teeth and bones are more likely to be preserved compared to skin, tissues, and organs. As a result, most fossils originate from a time span nearly 600 million years ago, when organisms began to evolve hard parts and skeletons.
Answer:
4.86×10^23 lead molecules
Explanation:
Using the provided equation, 2 moles of ammonia produces 3 moles of lead.
Thus:
2 mol NH3/ 3 mol Pb
By utilizing this proportion, we can calculate the quantities for each molecule. For 5.38 mol NH3:
(5.38 NH3)(3 Pb/ 2 NH3) = (5.38)(3/2) mol Pb = 8.07 mol Pb
Next, we will apply Avogadro's number to determine the total number of molecules.
(8.07)(6.02×10^23) = 4.86×10^23 lead molecules
