Answer:
KNO2, KBr
Explanation:
Chemical compounds are any substance composed of identical molecules consisting of atoms of two or more chemical elements. So NO2 and KBr are compounds, Br2 and Fe are not. 
 
        
             
        
        
        
Answer:
oxygen and silicon, both are common 
 
        
             
        
        
        
2.24 liters is the volume of the gas if pressure is increased to 1000 Torr.
Explanation:
Data given:
Initial volume of the gas V1 = 2.6 liters
Initial pressure of the gas P1 = 860 Torr 1.13 atm
final pressure on the gas P2 = 1000 Torr 1.315 atm
final volume of the gas after pressure change V2 =?
From the data given above, the law used is :
Boyles Law equation:
P1V1 = P2V2
V2 = P1V1/P2
    = 1.13 X 2.6/ 1.31
   = 2.24 Liters 
If the pressure is increased to 1000 Torr or 1.315 atm the volume changes to 2.24 liters. Initially the volume was 2.6 litres and the pressure was 860 torr.
 
        
             
        
        
        
Answer:
Option B. Malleable, Conductor, High melting point, Lustrous
Explanation:
Mg has a higher melting point because of the strong electrostatic force of attraction between the magnesium ions (Mg^2+). The rest properties listed are all general properties of metals 
 
        
             
        
        
        
Answer:
Color change
Explanation:
If it is a chemical change, then the color will change. Sometimes chemical changes also cause fizzing and bubbling.