5.4 x 10²³ molecules
Explanation:
Given parameter
Volume of gas = 20L
Condition of reaction = STP
Unknown:
number of molecules
Solution:
The number of molecules of a substance is given by;
Number of molecules = Number of moles x avogadro's constant
Number of moles at stp =
Number of moles of SO₂ = = 0.893mole
Number of molecules = 0.893 x 6.02 x 10²³ = 5.4 x 10²³ molecules
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Answer : The mass of ammonia present in the flask in three significant figures are, 5.28 grams.
Solution :
Using ideal gas equation,
where,
n = number of moles of gas
w = mass of ammonia gas = ?
P = pressure of the ammonia gas = 2.55 atm
T = temperature of the ammonia gas =
M = molar mass of ammonia gas = 17 g/mole
R = gas constant = 0.0821 L.atm/mole.K
V = volume of ammonia gas = 3.00 L
Now put all the given values in the above equation, we get the mass of ammonia gas.
Therefore, the mass of ammonia present in the flask in three significant figures are, 5.28 grams.