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Alborosie
3 years ago
12

Can someone help me please??

Chemistry
1 answer:
Xelga [282]3 years ago
4 0

41) Answer is: the average atomic mass of chromium is 52.056.

Ar(⁵⁰Cr) = 50.

ω(⁵⁰Cr) = 4.34% ÷ 100%.

ω(⁵⁰Cr) = 0.0434; relative abundance of chromium-50.

Average mass can calculate by summary of percentege of each isotope.

Ar(Cr) = Ar(⁵⁰Cr) · ω(⁵⁰Cr) + Ar(⁵²Cr) · ω(⁵²Cr) + Ar(⁵³Cr) · ω(⁵³Cr) + Ar(⁵⁴Cr) · ω(⁵⁴Cr).

Ar(Cr)= 50 · 0.0434 + 52 · 0.8379 + 53 · 0.095 + 54 · 0.0237.

Ar(Cr) = 2.17 + 43.571 + 5.035 + 1.280

Ar(Cr) = 52.056.

42) Chlorine has atomic number 17, it means it has 17 protons and 17 electrons.

Electron configuration of chlorine atom: ₁₇Cl 1s² 2s² 2p⁶ 3s² 3p⁵.

Chloride is negative ion of chlorine. Chloride is formed when chlorine gain one lectron.

Chloride anion has 17 protons and 18 electrons (like argon-noble gas).

The electron configuration for the chloride ion: ₁₇Cl⁻ 1s²2s²2p⁶3s²3p⁶.

43) Anwser is: the percent by mass of hydrogen in aspirin is 4.48%.

% calculate by atomic mass of element multiply number of that element in molecule divided by molecular mass of molecule.

Ar(H) = 1.008; the relative atomic mass of hydrogen atom.

Mr(C₉H₈O₄) = 9 · Ar(C) + 8 · Ar(H) + 4 · Ar(O).

Mr(C₉H₈O₄) = 180.157.

ω(H)= 8 · Ar(H) ÷ Mr(C₉H₈O₄) · 100%.

ω(H) = 8 · 1.008 ÷ 180.157 · 100%.

ω(H) = 4.48 %.

44) Balanced chemical reaction:

Cd(NO₃)₂ + 2NH₄Cl → CdCl₂ + 2NH₄NO₃.

This chemical reaction is double displacement reaction - cations (Cd²⁺ and NH₄⁺) and anions (NO₃⁻ and Cl⁻) of the two reactants switch places and form two new compounds.

Cd(NO₃)₂ is cadmium nitrate.

NH₄Cl is amonium chloride.

CdCl₂ is cadmium chloride.

NH₄NO₃ is ammonium nitrate.

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