Answer:

Explanation:
Hello,
For the given chemical reaction:

We first must identify the limiting reactant by computing the reacting moles of Al2S3:

Next, we compute the moles of Al2S3 that are consumed by 2.50 of H2O via the 1:6 mole ratio between them:

Thus, we notice that there are more available Al2S3 than consumed, for that reason it is in excess and water is the limiting, therefore, we can compute the theoretical yield of Al(OH)3 via the 2:1 molar ratio between it and Al2S3 with the limiting amount:

Finally, we compute the percent yield with the obtained 2.10 g:

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Given :
Initial concentration of nitric acid,
.
Final concentration of nitric acid,
.
Volume of
, 
To Find :
Volume needed(
).
Solution :
We know,

Hence, this is the required solution.
Answer: The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration—eons, eras, periods, epochs, and ages.
Explanation: I learned about it the other day
Answer:
Physical change
Explanation:
A physical change is one in which no new substance is formed and can be reversed using physical methods.
When we mix the salt and water, we have merely carried out a physical change. No new substance was formed. To recover the salt, we simply heat the solution to dryness.
Hence, this is an example of a physical change.
Answer:
the number of moles of the gas is 0.00174 mol.
Explanation:
Given;
temperature of the, T = 300 K
volume of the gas, V = 1.45 L
Pressure of the gas, P = 3.0 kPa
The number of moles of the gas is calculated using Ideal gas equation, as follows;
PV = nRT
Where;
n is number of moles of the gas
R is the ideal gas constant, = 8.315 L.kPa/mol.K
n = PV / RT
n = (3 x 1.45) / (8.315 x 300)
n = 0.00174 mol.
Therefore, the number of moles of the gas is 0.00174 mol.