Achemistry teacher needs to determine what quantity of sodium hydroxide to order

To know the exact amount of sodium hydroxide that the teacher needs to order, we need to know how many students are there and the amount that each student uses.
We will then multiply these two values and get the amount needed to be ordered.

Since you have not provided such data in your question, I will just assume them to show the steps of the solution. You can then apply these steps to the values you have.

Now, assume that a class of 60 students and that each student needs to use 130 grams of sodium hydroxide to use during the lab.
This means that the teacher will order:
130 x 60 = 7800 grams = 7.8 kg of sodium hydroxide

Exothermic,  physical change after it is already baked