5. SEP Use Mathematics The mass of an isotope can be approximated by adding together the number of protons and neutrons in its nucleus. For example, a
carbon-12 nucleus has 6 protons and 6 neutrons, and its mass is approximately
12 amu. Look at the models for the two isotopes of boron. Each model shows the
isotope's natural percent abundance and the composition of its nucleus. Use the
data to calculate the approximate atomic mass of boron.
Spº
6n
2092
8092

Which of the following elements would you expect to have the lowest ionization energy value? fluorine, lithium, neon, nitrogen

How many moles of magnesium is 3.01 x10^22 atoms of magnesium?

Astudent is given a sample of a blue copper sulfate hydrate. he weighs the sample in a dry covered porcelain crucible and got a mass of 23.875 g for the crucible, lid, and sample. the mass of the empty crucible and lid was found earlier to be 22.652 g. he then heats the crucible to expel the water of hydration, keeping the crucible at red heat for 10 minutes with the lid slightly ajar. on colling, he finds the mass of crucible, lid, and contents to be 23.403 g. the sample was changed in the process to very light clue anhydrous cuso4. if there are again 100.0 g of hydrate, how many grams of cuso4 are in it? how many moles of cuso4? (hint: molar mass of cuso4 = 159.6 g / mole. what per cent of the hydrate is cuso4? you may convert the mass of cuso4 to moles.)