Sometimes negative sometimes positive, your answer is B!
 
        
             
        
        
        
<h3>
Answer: 144 g</h3>
Explanation:
   Mass of glucose = moles × molar mass
∴ Mass of glucose = 0.8 mol × 180 g mol⁻¹
                                =  144 g
∴ the mass of glucose you need to have 0.8 mol of glucose = 144 g
 
        
        
        
In the combustion process using excess oxygen, each mole of methane results to 1 mole of co2 while ethane produces 2 moles of Co2. Under same conditions, these can be translated to volume. Hence the total volume absorbed is 10 cm3 + 20 cm3 = 30 cm3.
        
             
        
        
        
Answer:
Explanation:
first to get the density of some thing you have to devide the mass by the volume so 0.00018 (divided) by 10 kg and that gives you ur answer 
 
        
             
        
        
        
One of the best buffer choice for pH = 8.0 is Tris with Ka value of  6.3 x 10^-9.
To support this answer, we first calculate for the pKa value as the negative logarithm of the Ka value: 	
     pKa = -log Ka
For Tris, which is an abbreviation for 2-Amino-2-hydroxymethyl-propane-1,3 -diol and has a Ka value of 6.3 x 10^-9, the pKa is	
     pKa = -log Ka 
            = -log (6.3x10^-9) 
            = 8.2
We know that buffers work best when pH is equal to pKa:
     pKa = 8.2 = pH 
Therefore Tris would be a best buffer at pH = 8.0.