Answer:
Explanation:
use the equation
 moles = mass/mr
=19.9/79.5
=0.250moles of CuO
then do the same for 
H = 2.02/1
=2.02 
so CuO is the limiting reagent because there is less amount of it.
Hope this helps  :)
 
 
        
             
        
        
        
The correct option is STRONTIUM.
Strontium is a group 2 element, that means it has two electrons in its outermost shell. This element will prefer to lose these two electrons in its outermost shell in order to attain the octet form, therefore, it will form electrovalent bond with non metals which it can donate two electrons to.
        
             
        
        
        
Answer: the gas molecules interact with one another 
Explanation:
 
        
             
        
        
        
Answer:
1,2,3
Explanation:
Heat gain implies that heat is absorbed by the system in order to make the stated phase transition possible.
Before a liquid changes to gas, intermolecular forces in the liquid are broken by energy supplied as heat.
Also, transition from solid to liquid requires energy to break intermolecular bonds.
Finally, sublimation requires input of energy in the form of heat.
 
        
                    
             
        
        
        
The answer of perimeter to this question is 36