Answer:
History of composition
Years	Material	Weight (grains)
1944–1946	gilding metal (95% copper, 5% zinc)	48 grains
1947–1962	bronze (95% copper, 5% tin and zinc)	48 grains
1962 – September 1982	gilding metal (95% copper, 5% zinc)	48 grains
October 1982 – present	copper-plated zinc (97.5% zinc, 2.5% copper)	38.6 grains
 
        
             
        
        
        
Answer:Four types of vaccines are currently available: Live virus vaccines use the weakened (attenuated) form of the virus. The measles, mumps, and rubella (MMR) vaccine and the varicella (chickenpox) vaccine are examples 
 
        
                    
             
        
        
        
The equation you use here is 
mass =moles x Mr
So:
Moles of K - 0.55mol
Mr of K - 39.1
Mass= 0.55x39.1 =21.505g
        
             
        
        
        
Answer:cathode
Explanation:It is also known as the galvanic cell or electrochemical cell. In the voltaic cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode.