Answer:
Option A (0.043 g) is the correct answer.
Explanation:
Given:
= 43 mg
As we know,

then,
⇒ 
               
 
Thus, the above is the correct alternative.
 
        
             
        
        
        
Answer:
Answer of question a is 345J.
Explanation:
In question a following is given in data:
-mass of iron (m) = 10.0 g
-temperature (ΔT) = final temperature- initial temperature= 100-25=  75 degree Celsius
-Specific Heat capacity of iron (c)= 0.46J/g°C.
Heat (Q)=?
Solution:
Formula for Heat is :
Q=m x c x ΔT
Q= 10 x 0.46 x 75
Q= 345 J.  
so, 345 joules of heat is needed to increase the temperature of 10 grams of iron.
- From the above formula all other questions can easily be solved from the same procedure.
 
 
        
             
        
        
        
The correct answer is C, as if you do not understand something, it's always best to ask for help, especially when performing a sensitive procedure.
 
        
                    
             
        
        
        
Answer:
The central value of the sets of observation can be mean, median or mode depending upon the kind of data provided as all are measure of central tendency.
Explanation:
 
        
             
        
        
        
It is false because an endothermic reaction will also start when energy is received from the environment when there is no solution involved