Consider the reaction 2 COF2 (g) ⇌ CO2 (g) + CF4 (g) Kc = 2.00 at 1000 °C. A pure sample of COF2 is heated to 1000 °C in an evacuated container and allowed to reach equilibrium. At equilibrium, [CF4 ] is 0.266 M. What percentage of the original sample of COF2 decomposed to reach equilibrium?

Idon't know hope someone you

The answer for this is a

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.

Ican't see the chart but the density of both nickel and cobalt is 8.90 g/cm3, so it would be one of those.