Answer:
C.
Explanation:
A chemical change happens when one chemical substance is transformed into one or more different substances, such as when iron becomes rust.
Answer:
The final temperature of the system is 42.46°C.
Explanation:
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
c = specific heat of water= 
= mass of water sample with 100 °C= 50.0 g
= mass of water sample with 13.7 °C= 100.0 g
= final temperature of system
= initial temperature of 50 g of water sample= 
= initial temperature of 100 g of water =
Now put all the given values in the given formula, we get


The final temperature of the system is 42.46°C.
In an acidic solution, the concentration of H+ is greater than the concentration of OH-. The pH will be less than 7.
In a basic solution, the concentration of OH- is greater than the concentration of H+. The pH will be greater than 7.
In a neutral solution, the concentration of H+ ions to OH-ions will be equal, and will therefore have a pH of 7. (This is due to water autoionization, which we usually ignore because it is small in other circumstances.)