Something made of pure iron<span> is softer </span>than steel<span> because the atoms can slip over one another. If other atoms like carbon are added, they are different from </span>iron<span> atoms and stop the </span>iron<span> atoms from sliding apart so easily. This makes the metal </span>stronger<span> and </span>harder<span>.</span>
        
                    
             
        
        
        
it is A Acid 
Explanation : Any substance that yields a hydrogen ion when placed in a water solution is called an acid. According to Arrhenius theory of Acids and Bases, Acids are those substances which on dissociation in solution generates ions. Whereas a Base is a substance that dissociates in the solution to produce ions.
 
        
             
        
        
        
Answer:
Option A. 9.4 L
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 8 L 
Initial temperature (T₁) = 293 K
Final temperature (T₂) = 343 K
Final volume (V₂) =?
V₁ / T₁ = V₂ / T₂
8 / 293 = V₂ / 343
Cross multiply 
293 × V₂ = 8 × 343
293 × V₂ = 2744
Divide both side by 293
V₂ = 2744 / 293
V₂ = 9.4 L
Therefore, the final volume of the gas is 9.4 L 
 
        
             
        
        
        
Answer:
20 mole of oxygen
Explanation:
1 mole of proprane reacts with 5 moles of oxygen so 4 time 5 equals 20