It’s
1.A
2.C
3.B
hope it’s correct
From the calculations, the half life of the material is 6.5 days.
<h3>What is radioactivity?</h3>
The term radioactivity has to do with the spontaneous disintegration of a specie.
Uisng the formula;
N=Noe^-kt
N= amount at time t = 0.135 Ci or 4.995 ×10^9 Bq
No = amount initially present = 1.75 x 10^12 Bq
k = rate constant = ?
t = time taken = 55 days
Hence;
4.995 ×10^9 = 1.75 x 10^12e^-55k
4.995 ×10^9/1.75 x 10^12 = e^-55k
2.85 * 10^-3 = e^-55k
ln2.85 * 10^-3 = -55k
k = ln2.85 * 10^-3/-55
k = 0.1066 day-1
Half life = 0.693/ 0.1066 day-1
= 6.5 days
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The reaction;
O(g) +O2(g)→O3(g), ΔH = sum of bond enthalpy of reactants-sum of food enthalpy of products.
ΔH = ( bond enthalpy of O(g)+bond enthalpy of O2 (g) - bond enthalpy of O3(g)
-107.2 kJ/mol = O+487.7kJ/mol =O+487.7 kJ/mol +487.7kJ/mol =594.9 kJ/mol
Bond enthalpy (BE) of O3(g) is equals to 2× bond enthalpy of O3(g) because, O3(g) has two types of bonds from its lewis structure (0-0=0).
∴2BE of O3(g) = 594.9kJ/mol
Average bond enthalpy = 594.9kJ/mol/2
=297.45kJ/mol
∴ Averange bond enthalpy of O3(g) is 297.45kJ/mol.
Filling out the table below following the outlined order:
- Calcium - symbol = Ca; Group =2; Period = 4; Ar = 134; Am =40.078u; Ph = solid; Density = 1.55; Bp = 1757K; Mp = 1115K.
- Vanadium - symbol = V; Group =5; Period = 4; Ar = 197; Am =50.9415u; Ph = solid; Density = 6.11; Bp = 3680K; Mp = 2183K.
- Manganese - symbol = Mn; Group =7; Period = 4; Ar = 127; Am = 54.938044u; Ph = solid; Density = 7.21; Bp = 2334K; Mp = 1519K.
- Cobalt: - symbol = Co; Group =9; Period = 4; Ar = 125; Am =58.933195 u; Ph = solid; Density = 8.90; Bp = 3200K; Mp = 1768K.
- Zinc: - symbol = Zn; Group = 12; Period = 4; Ar = 134; Am =65.38 u; Ph = solid; Density = 7.14; Bp = 1180K; Mp = 692.68K.
- Arsenic: - symbol = As; Group = 15; Period = 4; Ar = 197; Am = 74.9216 u; Ph = solid; Density = 5.75; Bp = 889K; Mp = 889K.
- Bromine: - symbol = Br; Group =17; Period = 4; Ar = 120; Am = 79.904 u; Ph = Liquid; Density = 3.1028; Bp = 332K; Mp = 265K.
<h3>Meaning of Element</h3>
An element can be defined as a substance that can not be broken down into simpler substances.
An element serves as a building blocks for compounds and mixtures.
In conclusion, each element and its property as requested in the table are given above.
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