Answer:
[NO₃⁻ ] = 2.596 M
Explanation:
Ca(NO₃)₂ dissolves in water according to the following equation:
Ca(NO₃)₂ ⇒ Ca²⁺ + 2NO₃⁻
The moles of Ca(NO₃)₂ that dissolve is found as followed:
(21.3 g) / (164.10 g/mol) = 0.1298... mol
The number of NO₃⁻ ions are related to the above quantity by the molar ratio:
(0.1298 mol Ca(NO₃)₂) (2NO₃⁻/Ca(NO₃)₂) = 0.2596...mol NO₃⁻
The concentration of the nitrate ions is then calculated:
[NO₃⁻ ] = (0.2596...mol) / (100.0ml) x (1000mL/L) = 2.596 M
Atomic radius decreases across a period because valence electrons are being added to the same energy level at the same time the nucleus is increasing in protons. The increase in nuclear charge attracts the electrons more strongly, pulling them closer to the nucleus.
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An example would be iodine has a lower relative atomic mass than tellurium, so it should come before tellurium in Mendeleev's table. In order to get iodine in the same group as the other elements with similar properties such as fluorine, chlorine, and bromine, he had to put it after tellurium, which broke his own rules.
<h2>Balance Chemical Equation</h2>
1. N2 + 3 H2 = 2 NH3
2. 2 KCIO3 = 2 KCI + 3 O2
3. 2 NaCI + F2 = 2 CI + 2 NaF
4. 2 H2 + O2 = 2 H2O
5. Pb(OH)2 + 2 HCl = 2 H2O + PbCl2
6. 2 AlBr3 + 3 K2SO4 = 6 KBr + Al2(SO4)3
7. CH4 + 2 O2 = CO2 + 2 H2O
8. C3H8 + 5 O2 = 3 CO2 + 4 H2O
9. 2 C8H18 + 25 O2 = 16 CO2 + 18 H2O
10. FeCl3 + 3 NaOH = Fe(OH)3 + 3 NaCl
11. 4 P + 5 O2 = 2 P2O5
12. 2 Na + 2 H2O = 2 NaOH + H2
13. 2 Ag2O = 4 Ag + O2
14. S8 + 12 O2 = 8 SO3
15. 6 CO2 + 6 H2O = C6H12O6 + 6 O2
16. 2 K + MgBr2 = 2 KBr + Mg
17. 2 HCl + CaCO3 = CaCl2 + H2O + CO2
18. HNO3 + NaHCO3 = NaNO3 + H2O + CO2 - already balanced
19. 2 H2O + O2 = 2 H2O2
20. 2 NaNO3 + H2SO4 = Na2SO4 + 2 HNO3
