General nemistry 4th Edition McQuarrie - Rock. Gallogly
University Science Bo
presented by Macmillan Lea
The combustion of propane may be described by the chemical equation
CHg(9) + 50,(9) 3 CO2(g) + 4H2O(g)
How many grams of O2(g) are needed to completely burn 20.3 g C2H2(g)?

Answer (b) supersaturation;

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.

The answer to your q it is d