Answer:
The answer is 3.14 g/mL
Step-by-step explanation:
The density of a substance can be found by using the formula
![density = (mass)/(volume)\\](https://img.qammunity.org/2021/formulas/chemistry/college/5r66iguuf1jwisyubqbjuqjov1grpr3z79.png)
From the question
mass = 78.51 g
volume = final volume of water - initial volume of water
volume = 45 - 20 = 25 mL
So we have
![density = (78.51)/(25) \\ = 3.1404](https://img.qammunity.org/2021/formulas/chemistry/high-school/2yp7fz6ug0kf1lopv4fythk9qme2at5an3.png)
We have the final answer as
3.14 g/mL
Hope this helps you