Technetium-99 is an ideal radioisotope for scanning organs because it has a half-life of 6.0 h and is a pure gamma emitter. suppose that 80.0 milligrams were of tc-99 were prepared at 6:00 am, how many milligrams of tc-99 would remain at 6:00 pm the same day? make sure to include units in your answer.

How would you reduce the volume of gas

The following reaction shows sodium carbonate reacting with calcium hydroxide. na2co3 + ca(oh)2 → naoh + caco3 how many grams of naoh are produced from 20.0 grams of na2co3? (molar mass of na = 22.989 g/mol, c = 12.01 g/mol, o = 15.999 g/mol, ca = 40.078 g/mol, h = 1.008 g/mol) 12.2 grams 15.1 grams 24.4 grams 30.2 grams

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.