To find the unit rate price per ounce for the hot chocolate, you can divide the total cost by the number of ounces.
The total cost of the hot chocolate is $5.00, and the volume is 20 ounces.
\[ \text{Unit rate price per ounce} = \frac{\text{Total cost}}{\text{Total ounces}} = \frac{5.00}{20} \]
Now, performing the calculation:
\[ \frac{5.00}{20} = 0.25 \]
Thus, the unit rate price per ounce for the hot chocolate is $0.25 per ounce.