Answer:
B: 2800 hydrogen atoms
C: 6760 hydrogen atoms
D: y=amount of oxygen atoms*2
Step-by-step explanation:
B: We know the formula for water is H2O. SO that means that there is 2 hydrogen atoms and 1 oxygen atom. So there is 2 times the amount of hydrogen atoms so we can do 1400*2=2800, So there is 2800 hydrogen atoms in the water. 
C: Same thing as B. 3380*2=6760
D: y=amount of oxygen atoms*2. Because there is one oxygen atom and two hydrogen atoms so 1*2=2.
 
        
             
        
        
        
Answer:
D
Step-by-step explanation:
What you need to do is find the slope of both lines. Perpendicular lines are the negative inverse of each other. The slope of the lie between points R and F is  (2-4)/(1+9)=-1/5. Now you need to find the line where the slop is 5. If you look at D, the slope of the line those points lie on is (25-15)/(4-2)=5 which makes D the answer. 
 
        
                    
             
        
        
        
I would say the object will float because the density of water is 999.99kg/m which is slightly less than 1g but still more than the object.