Answer: The new concentration of a solution of  is 0.2 M 10.0 mL of a 2.0 M
 is 0.2 M 10.0 mL of a 2.0 M  solution is diluted to 100 mL.
 solution is diluted to 100 mL.
Explanation:
Given:  = 10.0 mL,
 = 10.0 mL,       = 2.0 M
 = 2.0 M
 = 100 mL,
 = 100 mL,            = ?
 = ?
Formula used to calculate the new concentration is as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that the new concentration of a solution of  is 0.2 M 10.0 mL of a 2.0 M
 is 0.2 M 10.0 mL of a 2.0 M  solution is diluted to 100 mL.
 solution is diluted to 100 mL.
 
        
             
        
        
        
Answer: B) calcium nitrate
 
        
             
        
        
        
To calculate for the final temperature, we need to remember that the heat rejected should be equal to the absorbed by the other system. We calculate as follows:
Q1 = Q2
(mCΔT)1 = (mCΔT)2
We can cancel m assuming the two systems are equal in mass. Also, we cancel C since they are the same system. This leaves us,
 (ΔT)1 = (ΔT)2
(T - 80) = (0 - T)
T = 40°C
        
             
        
        
        
1) An example of a compound machine could be a pair of Scissors. Their are two different simple machines in the Scissors which make up the compound machine. Both of them being a Lever, and a Fulcrum.
Hope this helps!