Answer: -
When bismuth-212 undergoes alpha decay, it becomes ²⁰⁸Tl
Explanation: -
Mass number of ²¹²Bi = 212
Atomic number of ²¹²Bi = 83
When alpha decay occurs the mass number decreases by 4 and the atomic number decreases by 2.
Mass number of daughter = 212 - 4 = 208
Atomic number of daughter = 83 - 2 = 81
It is the atomic number of Thallium Tl.
Thus the daughter nucleide is ²⁰⁸Tl.
 
        
                    
             
        
        
        
Explanation:
A physical change is one that alters the physical properties of matter (particularly the form and state). 
A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes (evolution or absorption of energy in form of heat or light or both). 
 Now, the salient differences between physical and chemical changes;
- Physical changes are easily reversible whereas chemical changes are not easily reversible. 
- Physical changes lead to the production of no new kinds of matter whereas chemical changes leads to the production of new kinds of matter. 
- Physical changes involves no change in mass whereas chemical changes involves change in mass. 
- Physical changes require little energy whereas considerable amount of energy is needed for chemical changes. 
 
        
             
        
        
        
Answer:
Kc = [CO2], that is to say it is equal to the concentration of CO2
Explanation:
It is a heterogeneous equilibrium since the substances that participate in the reaction are in different phases
In the heterogeneous limestone decomposition reaction:
CaCO3(s) --> CaO(s) + CO2(g)
The equilibrium constants are:
Kc = [CO2(g)]; Kp = PCO2(g); Kc = Kp (R T)^
−(1−0) = Kp (R T)^
−1
The equilibrium situation is not affected by the amount of  solid or liquid, as long as these substances are present.
The equilibrium constant is independent of the  amounts of solids and liquids in equilibrium.
 
        
             
        
        
        
<span>Hydrogen fusion generates the energy for proton - proton chains and the carbon nitrogen oxygen cycle. It is the nuclear fusion of 4 protons to form a helium 4 nucleus.</span>