To determine how many tablespoons of vinegar Ellen will need for 16 color tablets, we start by establishing the ratio of vinegar to color tablets based on the information given.
Ellen needs 5 tablespoons of vinegar for every 2 color tablets.
First, we find out how many sets of 2 color tablets are in 16 color tablets:
\[ \text{Number of sets} = \frac{16 \text{ color tablets}}{2 \text{ color tablets per set}} = 8 \text{ sets} \]
Now, we calculate the total amount of vinegar needed by multiplying the number of sets by the amount of vinegar required per set:
\[ \text{Total vinegar} = 8 \text{ sets} \times 5 \text{ tablespoons of vinegar per set} = 40 \text{ tablespoons of vinegar} \]
Thus, Ellen will need a total of
\[ \boxed{40} \]
tablespoons of vinegar for 16 color tablets.