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.
Answer : One mole of an ideal gas occupies a volume of 22.4 liters at STP.
Explanation :
As we know that 1 mole of substance occupies 22.4 liter volume of gas at STP conditions.
STP stands for standard temperature and pressure condition.
At STP, pressure is 1 atm and temperature is 273 K.
By using STP conditions, we get the volume of 22.47 liter.
Hnece, the one mole of an ideal gas occupies a volume of 22.4 liters at STP.
Answer:
(a) 3:2; (b) 2:1
Explanation:
The Law of Multiple Proportions states that when two elements A and B combine to form two or more compounds, the masses of B that combine with a given mass of A are in the ratios of small whole numbers.
That is, if one compound has a ratio r₁ and the other has a ratio r₂, the ratio of the ratios r is in small whole numbers.
(a) Ammonia and hydrazine.
In ammonia, the mass ratio of H:N is r₁ = 0.2158/1
In hydrazine, the mass ratio of H:N is r₂ = 0.1439/1
The ratio of the ratios is:
(b) Nitrogen oxides
In nitrogen monoxide, the mass ratio of O:N is r₁ = 1.142/1
In dinitrogen monoxide, the mass ratio of O:N is r₂ = 0.571/1
The ratio of the ratios is:
If you are operating a power driven vessel that is underway in condition of restricted visibility, you are expected to do the following: sound prolonged blasts every two minutes. If the vessel is underway but is not moving, it is expected to sound two prolonged blast every two minutes. When one hears any of the signal above, one is expected to reduce speed to the minimum that is needed to keep on course.
2
refer to periodic table for explanation
