Answer:
10.7 g of KOH
Explanation:
First of all, we determine the reaction:
2K (s) + 2H₂O(l) → H₂(g) + 2KOH(aq)
We convert the mass of K, to moles → 7.5 g . mol/39.1 g = 0.192 moles
Ratio is 2:2, so the moles I have of K must produce the same moles of KOH. In this case, the produces moles of KOH are 0.192 moles.
We convert the moles to mass, to finish the answer:
0.192 mol . 56.1g /1mol = 10.7 g of KOH
We will take that molar mass of Pb(CO3)2 represents the total mass of all particles in this compound, ie it has value 100%.
M(Pb(CO3)2) = Ar(Pb) + 2xAr(C) + 6xAr(O) = 207.2 + 2x12 + 6x16= 327.2 g/mol
M(Pb) = 207.2 g/mol
From the date above we can set the following ratio:
M(Pb(CO3)2) : M(Pb) = 100% : x
327.2 : 207.2 = 100 :x
x = 63.33% of Pb there is in <span>Pb(Co3)2</span>
Explanation:
Let us assume that volumes is equal to spheres volume of nucleus.
fm = femto meter =
pm = pico meter =
Hence, calculate the volume as follows.
V =
=
= 82.4481 (cubic femtometers)
or, = 82
Now, we will calculate the volume of the atom as follows.
V =
=
= 1436758.4 (cubic picometers)
thus, we can conclude that volume of the nucleus is 82 and volume of the atom is 1436758.4 .
The answer for the following question is mentioned below.
<u><em>Therefore no of moles present in the gas are 1.12 moles</em></u>
Explanation:
Given:
Pressure of gas (P) = 1.2 atm
Volume of a gas (V) = 50.0 liters
Temperature (T) =650 K
To calculate:
no of moles present in the gas (n)
We know;
According to the ideal gas equation;
We know;
<u>P × V = n × R × T
</u>
where,
P represents pressure of the gas
V represents volume of the gas
n represents no of the moles of a gas
R represents the universal gas constant
where the value of R is 0.0821 L atm mole^{-1} K^-1
T represents the temperature of the gas
As we have to calculate the no of moles of the gas;
n =
n = \frac{1.2*50.0}{0.0821*650}
n = \frac{60}{53.365}
n = 1.12 moles
<u><em>Therefore no of moles present in the gas are 1.12 moles</em></u>
Answer:
the second one seems right :)
Explanation: