Answer : The pressure in the flask after reaction complete is, 2.4 atm
Explanation :
To calculate the pressure in the flask after reaction is complete we are using ideal gas equation.

where,
P = final pressure in the flask = ?
R = gas constant = 0.0821 L.atm/mol.K
T = temperature = 
V = volume = 4.0 L
= moles of
= 0.20 mol
= moles of
= 0.20 mol
Now put all the given values in the above expression, we get:


Thus, the pressure in the flask after reaction complete is, 2.4 atm
Answer:
Buffers are resistant to high pH changes.
Explanation:
This perfectly explains the reason why we use buffers. Buffers are substances which consist of a weak acid and its conjugate base. Buffers are resistant to significant pH changes upon addition of strong acids or bases. To illustrate this, let's say we have a buffer consisting of 0.1 mol of HF, a weak acid, and 0.1 mol of NaF (fluoride is a conjugate base of HF).
- Let's say we add some strong acid, in a general form, this acid would be represented as
. In this case, conjugate base will react and neutralize it to produce some amount of HF:
. - Similarly, if we add some strong base
, the acidic component will react with it to produce some amount of conjugate base:
. The ratio of HF to NaF in this case is held around the same value for addition of small amounts of strong acids/bases, so pH is kept almost constant, while in neutral water, pH would drastically increase or decrease.
In this question, the <span>patient needs to be given exactly 500 ml of a 5.0%. The content of the glucose should be:
</span>weight= volume * density* concentration<span>
500ml * 1mg/ml *5%= 25mg.
The </span><span>stock solution is 35%, then the amount needed in ml would be:
weight= volume * density* concentration
25mg= volume * 1mg/ml *35%
volume= 25/35%= 500/7= 71.43ml</span>
Answer: Endothermic reaction
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and
for the reaction comes out to be negative.
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and
for the reaction comes out to be positive.
As the energy of reactants is 180 kJ and that of products is 300 kJ, the energy of products is greater than that of reactants, which means the energy has been absorbed and reaction is endothermic.
Depression in freezing point (Δ

) =

×m×i,
where,

= cryoscopic constant =

,
m= molality of solution = 0.0085 m
i = van't Hoff factor = 2 (For

)
Thus, (Δ

) = 1.86 X 0.0085 X 2 =

Now, (Δ

) =

- T
Here, T = freezing point of solution

= freezing point of solvent =

Thus, T =

- (Δ

) = -