Answer:
-12162.47 joules (or -12000 joules when accounting for significant figures)
Explanation (btw I used 1 cal as 4.184 joules because SI units are better):
q = m c delta T
q = (70.9) (4.184) (25 - 66)  
q = (70.9) (4.184) (-41)
q = -12162.47 joules
 
        
             
        
        
        
Answer: possibly diffusion
Explanation:
all particles are in motion unless at a certain degree so they'd spread throughout the room diluting as they continue to spread out.
 
        
             
        
        
        
Answer:
Na(OH)² 
Explanation:
We look for the charges in the periodic table
 
        
             
        
        
        
Answer:
Second Law
Explanation:
Newton's second law states that the acceleration caused in a body is directly proportional to the force applied and inversely proportion to the mass of the body.
This is given by : 

In this case the suggestion given to reduce the aircraft's cargo load is the right move as reducing the load on the aircraft will decrease the mass of the whole aircraft.  This in turn will help the aircraft to accelerate more as acceleration inversely varies with mass. Thus the aircraft will be able to reach its flying speed even on a short run way.
Hence, Newton's second law is applied.
 
        
             
        
        
        
Answer:
0.4 moles
Explanation:
To convert between moles and grams you need the molar mass of the compound. The molar mass of of CaCO3 is 100.09g/mol. You use that as the unit converter.
40gCaCO3* 1mol CaCO3/100.09gCaCO3 = 0.399640 mol CaCO3
This rounds to 0.4 moles CaCO3