How many moles are in 5.1 x 10^23 formula units of CaCl2? please show work, will give brainliest

Analyze how limestone is weathered and identify the features that are formed as a result of this dissolution

What is the empirical formula for c4h8o2

8) a mixture of he, ne and ar has a pressure of 7.85 atm. if the ne has a mole fraction of 0.47 and 8) ar has a mole fraction of 0.23, what is the pressure of he? a) 4.2 atm b) 3.7 atm c) 5.5 atm d) 2.4 atm e) 1.8 atm