Answer:
The mass of the surrounding is 

Step-by-step explanation:
From the question we are told that 
 The mass of 
 is
 is 

 The mass of water is 

 The chemical equation for the dissociation process is
 

 The specific heat capacity of the mixture is 

 
The combined mass of the solution is 
 
 
 
 

The mass of the surround here is the mass of the coffee-cup calorimeter and this contain the mixture ( water and the NaOH ) so the mass of the surrounding is 
 
