Answer:
a)calculated molarity of NaOH would be lower
b) calculated molarity of NaOH would be lower
c) calculated molarity of NaOH would be lower
d) calculated molarity of NaOH would be unaffected
Explanation:
Let us recall that the reaction of NaOH and HCl is as follows;
NaOH(aq) + HCl(aq) ----> NaCl(aq) + H2O(l)
Since the reaction is 1:1, when the number of moles of HCl reacting with NaOH is low due to dilution, the calculated molarity of NaOH also becomes less than it's accurate value.
When 40mL of water is added to the titration flask rather than 25ml of water, the acid is more dilute hence less number of moles of acid than necessary reacts with the base thereby yielding a less than accurate value of the molarity of NaOH.
If the burette wet with water is not rinsed with NaOH solution, the concentration of the NaOH in the burette decreases due to dilution with water and a less than accuracy value is calculated for the molarity of NaOH.
If five drops of phenolphthalein is used instead of one or two drops, there is no qualms since enough phenolphthalein may be added to ensure that a sharp end point is obtained.
Molar mass HNO₃ = 63.0 g/mol
number of moles = 3.94 / 63.0 => 0.0625 moles
Volume = moles / molarity
V = 0.0625 / 1.50
V = 0.04166 L x 1000 = 41.66 mL
hope this helps!
Answer:
Inspiration
Explanation:
This question is on application of Boyle's law; <u>pressure is inversely proportional to volume</u>.when we inhale air, the diaphragm and the muscles in the ribs contract thus increasing the volume in the lungs.Increased volume of the lungs cause the pressure to decrease.During exhaling, the diaphragm and muscles in the ribs relax, making the lungs to recoil and reduce in volume to force air out.Pressure in the lungs is increased than that in the environment making air to move out.
