How many hydrogen atoms are involved in this reaction? 3
        
             
        
        
        
 Answer:
2 half-lives=0.8
6 half-lives= 0.05
Explanation
Half-lives are constant and always decrease by half, implying that the concentration decreases by half at a consistent rate.
3.2/2= 1.6/2= 0.8 is two half-lives
3.2/2= 1.6/2= 0.8/2= 0.4/2= 0.2/2= 0.1/2=0.05 is six half-lives
 
        
             
        
        
        
Answer:
1 and 2
Explanation:
The postulates of Dalton's atomic theory are;
- Matter is made up of indivisible particles known as atoms.
- Atoms of same elements have same properties while atoms of different elements have different properties.
- Atoms of different elements combine in fixed ratios to form compounds.
- Atoms are neither created nor destroyed. 
- The formation of new products (compounds) results from the rearrangement of existing atoms (reactants).
By comparing the postulates above and those in the questions, we find that only the following postulates are part of the daltons atomic theory;
1. Atoms combine in fixed ratios of whole numbers.
2. Atoms of each element have different properties.
 
        
             
        
        
        
Answer:
D 
Explanation:
Cell membrane, also called plasma membrane, thin membrane that surrounds every living cell, delimiting the cell from the environment around it.