What mass of Na2SO4 is needed to make 0.12L of 31.57m solution? Na=239 S=32g O=16g

Plzz a sample of table sugar (sucrose, c12h22o11) has a mass of 7.801 g. ● a) calculate the number of moles of c12h22o11 in the sample b) calculate the number of moles of each element in c12h22o11 (number of moles of c, number of moles of h & number of moles of o) in the sample. (use your answer from part a as your starting point.) show your work and highlight your final answer. calculate the number of atoms of each element in c12h22o11 (number of atoms of c, number of atoms of h & number of atoms of o) in the sample. (use your answers from part b as your starting for each element.) show your work and highlight your final answer.

Who discovered a pattern to the elements in 1869?

Stoichiometry- i need with 14 and 15! an explanation would be appreciated!