180 grams the way to calculate this is to know the molar mass of each of the elements C6 means there are 6 carbon atoms carbons molar mass is 12 grams so 12*6=72grams of carbon. Hydrogens molar mass is 1 gram so 12 hydrogen atoms 12 grams. Oxygens molar mass is 16 grams so 16*6=96 grams add it all together gives molar mass. Molar mass is grams when using avogadros number you need to know elements atomic mass and have periodic table handy for these sorts of questions. Molar mass of an element is atomic mass only difference being one is in grams other in tiny atomic units.
We can use to formula . Here, N(A) is the final amount. N0 is the initial amount. t is the time elapsed, and is the half life. Plugging in, we get the answer above.