Who came up with the idea that all the continents were once joined together

How many molecules of sucrose c12h22o11 are there in 454 grams of sucrose

In the particles are arranged in a regular, repeating pattern. a)a crystalline liquid b)a crystalline solid c)all gases d)all solids

In the following table, all the columns for the element calcium are filled out correctly. element electron structure of atom electron structure of ion net ionic charge calcium 1s22s22p63s23p64s2 1s32s22p63s23p64s1 +1 true false