Given data Atomic mass of Ra= 226g/mol
no. of moles =1.0/226g/mol =0.04424moles
no. of atoms in 0.044moles
no. of atoms =no. of moles x avogadro's number
= 0.044x 6.022 x10^23 = 0.264968 x 10^22
If 10^15 atoms of Ra produce 1,373*10^4 atoms of<u> Rn per second</u> then 2,66 *10^21 forms 3,658*10^10 atoms of Rn per second.
Day has 246060=86400 s
That means that 2,66x10^21 atoms of Ra produces 3,16 x10^15 atoms of Rn in a day.
N(Rn)=3.16* 10 ^15 n(Rn)=N/NA
n(Rn)=5,25*10−9 pV=nR*T
T=273.15K R=8,314
p=101325Pa V=n∗R∗T/p
V=5.25∗10^−9 ∗ 8.314 ∗ 273.15 / 101325
V=1.1810^−10 m^3 = 118 x10^-7 liters of Rn, measured at STP, are produced per day by 1.0 g of Ra
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Answer:
33.8 m
Explanation:
(a) We want to know the molality of nitric acid in a concentrated solution of nitric acid (68.0% HNO₃ by mass).
Step 1: Determine the mass of HNO₃ and water in 100 grams of solution.
Step 2: Convert the mass of HNO₃ to moles.
Step 3: Convert the mass of water to kilograms.
Step 4: Calculate the molality.
(b)
Step 1
In 100 g of solution, there are 68.0 g of HNO₃ and 100 g - 68.0 g = 32.0 g of water.
Step 2
The molar mass of HNO₃ is 63.01 g/mol. The moles corresponding to 68.0 g are:
68.0 g × (1 mol/63.01 g) = 1.08 mol
Step 3
The mass of water is 32.0 g = 0.0320 kg
Step 4
The molality of HNO₃ is:
m = moles of solute / kilograms of solvent
m = 1.08 mol / 0.0320 kg
m = 33.8 m
Answer:
Mass = 72.52 g
Explanation:
Given data:
Mass of hydrogen phosphate produced = ?
Mass of P₂O₅ react = 105.9 g
Solution:
Chemical equation:
P₂O₅ + 3H₂O → 2H₃PO₄
Number of moles of P₂O₅:
Number of moles = mass/molar mass
Molar mass of P₂O₅ 283.9 g/mol
Number of moles = 105.9 g/ 283.9 g/mol
Number of moles = 0.37 mol
Now we will compare the moles of P₂O₅ with H₃PO₄ from balance chemical equation.
P₂O₅ : H₃PO₄
1 : 2
0.37 : 2/1×0.37= 0.74 mol
Mass of H₃PO₄ :
Mass = number of moles × molar mass
Mass = 0.74 mol × 98 g/mol
Mass = 72.52 g
Answer:
60
Explanation:
there's 5 lines, and 800-700=100 each line represents 20 because 20×5=100.
from a to b, there's 3 lines and 3×20=60
This is Arabic i think you chose chemistry so I think you have the wrong page.
Write it in English if its a question :)
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