its exothermic. exothermic means the reaction gives out heat. [exo meaning outside and thermic meaning heat] because its a combustion reaction, fire is there meaning lots of heat. 
endothermic means it takes in heat. a good example is ammonium and water (NH3 +H20) 
<span>most chemical reaction are exothermic</span>
        
             
        
        
        
1. This can be due to the dissolving of the solid in liquid and form a solution. 
Dissolving is a physical property because dissolving doesn't form new substances and the chemical composition of the solid is not changed. 
The color building up over the time can be due to the rate of dissolving of the solid and amount of particles have been dissolved.
Example:
- Dissolving of CuSO₄ solid in water. 
 - This develops a blue color.
 
2. This can be due to the chemical reaction between the solid and liquid.
Chemical reaction is a chemical property because from reacting substances new substances can be formed which the chemical formula is different from initial substances. 
The color building up over the time can be due to the rate of the reaction and the amount of reactants.
Example:
- The reaction between calcium metal with water.
 - The color of Ca(OH)₂ is white color. 
 - Reaction is 
 
        Ca(s) + 2H₂O(l) → Ca(OH)₂(aq) + H₂(g)
 
        
             
        
        
        
Answer: Option (a) is the correct answer.
Explanation:
Atomic number is the sum of only total number of protons present in an element. Whereas mass number is the sum of total number of both protons and neutrons present in an element.
For example, given atom has mass number as 15 and its atomic number is 7.
Therefore, number of neutrons present in it will be calculated as follows.
                     Mass number = no. of protons + no. of neutrons
                          15 = 7 + no. of neutrons
                     no. of neutrons = 15 - 7 
                                                = 8
Thus, we can conclude that the given atom contains 8 neutrons in the nucleus. 
 
        
             
        
        
        
Answer:
First Part: branched chain, cycloalkane, straight chain
Second Part: straight chain, branched chain, cycloalkane.
Explanation:
Edg 2021