To find out how much jam Vincent jarred in 4 days using unit rates, we first determine the unit rate of jam produced per day.
Vincent jarred 14 liters in 2 days, so we can find the rate by dividing the total liters by the total number of days:
\[ \text{Unit Rate} = \frac{14 \text{ liters}}{2 \text{ days}} = 7 \text{ liters per day} \]
Now that we have the rate, we can calculate how much jam he would jar in 4 days.
\[ \text{Jam in 4 days} = 7 \text{ liters/day} \times 4 \text{ days} = 28 \text{ liters} \]
Therefore, Vincent jarred 28 liters of jam in 4 days.