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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The stoichiometry of the reaction gives the molar ratio in which the reactants react with each other and the ratio in which products are formed.
The coefficients of the reactants in the reaction follow the stoichiometry
the balanced chemical equation for the reaction is as follows;
2C₃H₆(g) + 9O₂(g) ---> 6CO₂(g) + 6H₂O(l)
Solutions for your questions are the following:
1. remaining amount is equal to:960 g : 100% = 30 g : xx = 30 g * 100% / 960 g
= 3.125%
= 0.03125
Now, we use this formula to calculate the number of half-lives:(1/2)ⁿ = x,
so,(1/2)ⁿ = 0.03125
to calculate n, use this equation:
n*log(1/2) = log(0.03125) n = log(0.03125)/log(1/2)
= log(0.03125)/log(0.5)
= -1.505/-0.301
n=5
Ifn = 5T = 15 min
Then
L = T/nL = 15 min/5
= 3 minutes
2. You should pick filtration. It is use to separate heterogeneous mixtures just like in the problem stated.
Answer:
39.6 g
Explanation:
The equation of the reaction is;
2Mg(s) + O2(g) --------> 2MgO(s)
To obtain the limiting reactant;
Number of moles in 26.4 g of Mg = 26.4g/24 g/mol = 1.1 moles
If 2 moles of Mg yields 2 moles of MgO
1.1 moles of Mg yields 1.1 * 2/2 = 1.1 moles of MgO
Number of moles in 26.4 g of O2 = 26.4 g/32g/mol = 0.825 moles
If 1 mole of O2 yields 2 moles of MgO
0.825 moles of O2 yields 0.825 moles * 2/1 = 1.65 moles of MgO
Hence Mg is the limiting reactant.
Theoretical yield of MgO = 1.1 moles of MgO * 40 g/mol = 44 g
Percent yield = 90%
Percent yield = actual yield/theoretical yield * 100
Actual yield = Percent yield * theoretical yield/100
Actual yield = 90 * 44/100
Actual yield = 39.6 g
Answer:
Element name: Krypton
Symbol: Kr
Mass Number: 79 AMU
Charge: 0, electrons and protons cancel out.
ion: none, it is a halogen.
Explanation:
Krypton is the 36th element on the periodic table and has 36 protons. The mass is protons plus nuetrons so 36 + 43 is 79 AMU or Atomic Mass Units.