It will take 1.11 min to heat the sample to its melting point.
Melting point = - 20°C 
Boiling point = 85°C
∆H of fusion = 180 J/g
∆H of vap = 500 J/g 
C(solid) = 1.0 J/g °C
C(liquid) = 2.5 J/g °C
C(gas) = 0.5 J/g °C
Mass of sample = 25 g
Initial temperature = - 40°C
Final temperature = 100°C
Rate of heating = 450 J/min
Specific heat capacity formula:- q = m ×C×∆T
Here, q = heat energy 
         m = mass
         C = specific heat
       ∆T = temperature change
Melting point = - 20°C 
C(solid) = 1.0 J/g °C
∆T = final temperature - initial temperature = -20 - (-40) = 20
Put these value in  Specific heat capacity formula 
 q = m ×C×∆T
q = 25×1.0×20
    =500J
The Rate of heating = 450 J/min
i.e. 450J = 1min
so, 500J = 1.11min
1.11 minutes does it take to heat the sample to its melting point.
The specific heat capacity is defined as the amount of heat absorbed in line with unit mass of the material whilst its temperature increases 1 °C.
Learn more about specific heat capacity here:- brainly.com/question/26866234
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Answer:
0.92^n
Explanation:
Given that :
Initial amount of vinegar = 1 Litre
Number of litres removed repeatedly = 0.08 Litre
Since the amount removed each time is constant, then ;
Initial % = 100% = 100/100 = 1
. Using the relation :
Amount of vinegar in mixture :
Initial * (1 - amount removed / initial amount)^n
n = number of times repeated 
1 * (1 - 0.08/1)^n
1 * (1 - 0.08)^n
1 * 0.92^n
Hence, 
For nth removal, 
Concentration will be :
0.92^n ; for n ≥ 1
 
        
             
        
        
        
Consisting of parts all of the same kind material.
 
        
                    
             
        
        
        
Answer:
It is calcium phosphide.
Explanation:
Calcium phosphide is a salt like material that is composed of calcium and phosphorus in the ratio of 2:5. It has the appearance of red brown Crystalline salt.
It is use as rodenticide to kill rats.
It is also use in fire works.
 
        
                    
             
        
        
        
Answer:
The correct answer is entropy change of the surrounding plus the entropy change of the system must be positive.
Explanation:
The term entropy is a state function.Entropy can be defined as the disorder or randomness of the molecules in a system.
  A spontaneous reaction is a type of reaction which deals with the release of free energy.The change of free energy in case of spontaneous reaction is always negative.
  According to the second law of thermodynamics a spontaneous reaction will occur in a system if the total entropy of both  system and surrounding increases during the reaction.