Elemental copper would be a pure substance.
        
             
        
        
        
Osmolarity=osmole  of  the  solute/litres  of  the  solution
ionic  equation  for  dissociation  of  CaCl2  is
CaCl2--->Ca2+   +2Cl-
total osmoles  for  reaction are    1(Ca2+)  + 2(Cl-)= 3 osmoles
therefore
 
0.50 moles of  CaCl2  x 3 osmoles/ 1mole of  CaCl2 = 1.5osmoles
osmolarity=1.5 /1.0  L=1.5 osmol/l
        
             
        
        
        
Answer:
17 
Explanation:
the mass number of the element which is protons and neutrons is 17+18=35
electronic configuration is 2, 8, 7
valency of the element is 1 therefore the atomic number is 17 
 
        
                    
             
        
        
        
Answer:
A model or simulation is only as good as the rules used to create it. It is very difficult to create an entirely realistic model or simulation because the rules are based on research and past events. The main disadvantage of simulations is that they aren't the real thing.
Explanation: