Melting point = 63.3 °C Boiling Point = 775.8 °C Specific heat (solid) = 0.816 J/g °C Specific heat (liquid) = 4.4 J/g °C ΔHfus = 0.965 J/g ΔHvap = 6.4 J/g. Calculate the TOTAL amount of energy required to heat 31.8 grams of the substance from 11.2 °C to 446 °

Neither model is able to show the reactivity of potassium.

Ithink about 50 % of an original isotope's number of atoms remain

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.