Answer:
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
Explanation:
Given data:
Atomic mass of silicon= ?
Percent abundance of Si-28 = 92.21%
Atomic mass of Si-28 = 27.98 amu
Percent abundance of Si-29 = 4.70%
Atomic mass of Si-29 = 28.98 amu
Percent abundance of Si-30 = 3.09%
Atomic mass of Si-30 = 29.97 amu
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (92.21×27.98)+(4.70×28.98)+(3.09×29.97) /100
Average atomic mass = 2580.04 +136.21+92.61 / 100
Average atomic mass = 2808.86 / 100
Average atomic mass = 28.08amu.
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
.............................
Answer:
Cl
Explanation:
The element Cl will have the strongest ionization energy from the given choices. Most non-metals have higher ionization energy compared to metals.
Ionization energy is the energy required to remove the most loosely held electron from the gaseous phase of an atom.
- As you go from left to right on the periodic table, it increases progressive
- From top to bottom, the ionization energy reduces significantly.
- The attractive force between the protons in the nucleus and the electrons plays a very important role.
- In metals, they have very large atomic radius, the attractive force on the outer electrons is very weak.
- This is not the case in non-metals
Answer: 1. CaO + H2O => Ca(OH)2
2. P4 + 5O2 => 2P2O5
3. 2 Ca + O2 => 2 CaO
4. 8 Cu + S8 => 8 CuS
5. CaO + H2O => Ca(OH)2
6. S8 + 8 O2 => 8 SO2
7. 3 H2 + N2 => 2 NH3
8. H2 + Cl2 =>2 HCl
9. 16 Ag + S8 => 8 Ag2S
10. Cr + O2 => 2Cr2O3
11. 2Al + 3Br2 => 2AlBr3
12. 2Na + I2 => 2NaI
13. 2H2 + O2 =>2 H2O
14. 4 Al + 3O2 => 2 Al2O3
Explanation:
Atomic mass silicon = 28.085 u
1 mol Si ---------------- 28.085 g
? ------------------------ 245 g
245 x 1 / 28.085 => 8.72 mol
answer A
