What is the concentration, in M, of a KBr solution that contains 0.0688 moles of KBr dissolved in 0.250 liters?
2.75 M
3.63 M
1.78 M
0.275 M

18

Higher temperature = molecules move around faster. and vice versa.

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.