The cost of washing soda is Rs 40 per kg and of anhydrous Na2CO3 is Rs 100per kg. Find the cost per mole of each reagent. Which is cheaper to buy either washing soda or anhydrous Na2CO3 and why?

Answer246 k;

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.