What is the weight of $3.01 \times 10^{23}$ molecules of ammonia in grams?

The atomic weights of two elements $A$ and $B$ are $40$ and $80$ respectively. If $x \ g$ of $A$ contains $y$ atoms,how many atoms are present in $2x \ g$ of $B$?

At $STP$,$32 \ g$ of $O_2$ contains $6.022 \times 10^{23}$ molecules. How many atoms does $32 \ g$ of sulfur $(S)$ contain under the same conditions?

Find the number of electrons present in $34 \ g$ of $NH_{3(g)}$. (Express your answer in terms of $N_A$)

What will be the mass of one atom of $^{12}C$ in grams?

Which of the following represents $180 \ g$ of water correctly?