Hey There:
First order  half life equation :
T 1/2  = ln ( 2 ) /K
T 1/2 = 0.693 / 3.40
T 1/2 = 0.204 s
Answer B
 
        
                    
             
        
        
        
You answer this by using the pH formula and and the relation of pH and pOH, pH = -log[H+] and 14 = pH + pOH. The correct classification are as follows:
<span>A. [H2O+]=6.0x10^-12
basic
B. [H3O+]=1.4x10^-9
basic
C. [OH-]=5.0x10^-12
acidic
D. {OH-]=3.5x10^-10
acidic
Hope this answers the question.
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Hi there! Let's solve this problem shall we! 
⠀Volume = 10g
       Mass = 2 mL 
In this specific problem, they are asking us to find the <u><em>density </em></u>of the object. So,<u><em> using the information given to us</em></u> (volume and mass), let's solve the problem! 
Now, if you remember, D = M ÷ V
So, let's fill in the blanks! 
D = Our unknown value 
M = 2mL 
V = 10g 
Here is the filled out formula: 
D = M ÷ V
D = 2mL ÷ 10g
D = 5 g/mL 
*Make sure you put the units for your final solution!*
 
        
             
        
        
        
To determine the standard heat of reaction, ΔHrxn°, let's apply the Hess' Law.
ΔHrxn° = ∑(ν×ΔHf° of products) - ∑(ν×ΔHf° of reactants)
where
ν si the stoichiometric coefficient of the substances in the reaction
ΔHf° is the standard heat of formation
The ΔHf° for the substances are the following:
CH₃OH(l) = -238.4 kJ/mol
CH₄(g) = -74.7 kJ/mol
O₂(g) = 0 kJ/mol
ΔHrxn° = (1 mol×-74.7 kJ/mol) - ∑(1 mol×-238.4 kJ/mol)
ΔHrxn° = +163.7 kJ