- Welcome to ChemTopper Free Chemistry Help .
ChemTopper Free Chemistry Help
Free Chemistry Help
Recent posts
#71
Organic Chemistry / NMR J Value Questions
Last post by amimi - February 17, 2026, 12:46:38 AMHello! I have a few questions related to NMR that I would love clarification on, thank you so much!
#72
Organic Chemistry / NMR determining molecule from ...
Last post by amimi - February 17, 2026, 12:45:51 AMHello! I have a few questions related to NMR that I would love clarification on, thank you so much!
#73
Organic Chemistry / NMR multiple choice questions
Last post by amimi - February 17, 2026, 12:44:43 AMHello! I have a few questions related to NMR that I would love clarification on, thank you so much!
#74
AP Chemistry / Re: Unit 8 (Acids and Bases Qu...
Last post by uma - February 12, 2026, 06:19:34 PM Substances that donate H⁺ in water are Brønsted–Lowry acids, and substances that accept H⁺ are Brønsted–Lowry bases.
H₃PO₄ and H₂PO₄⁻ can both act as Brønsted–Lowry acids because each can donate a proton. However, H₃PO₄ is a stronger acid than H₂PO₄⁻ since it carries no negative charge and more readily donates H⁺.
I⁻ and Ba(OH)₂ act as bases.
I⁻ can accept a proton to form HI.
Ba(OH)₂ provides OH⁻ ions, which readily accept H⁺ to form water.
H₂PO₄⁻ is amphiprotic—it can also act as a base by accepting a proton to form H₃PO₄.
H₃PO₄ and H₂PO₄⁻ can both act as Brønsted–Lowry acids because each can donate a proton. However, H₃PO₄ is a stronger acid than H₂PO₄⁻ since it carries no negative charge and more readily donates H⁺.
I⁻ and Ba(OH)₂ act as bases.
I⁻ can accept a proton to form HI.
Ba(OH)₂ provides OH⁻ ions, which readily accept H⁺ to form water.
H₂PO₄⁻ is amphiprotic—it can also act as a base by accepting a proton to form H₃PO₄.
#75
AP Chemistry / Unit 8 (Acids and Bases Query)...
Last post by Chandrasekhar - February 12, 2026, 04:48:57 PMHi Mam,
I was wondering how to identify the Bronsted Lowry Acids and Bases?
Thank you for the help!
I was wondering how to identify the Bronsted Lowry Acids and Bases?
#76
AP Chemistry / Re: Quiz 6.6 - AP chemistry qu...
Last post by uma - February 06, 2026, 12:26:12 AMYour method is correct however the value is for two moles of C4H10.In the balanced equation it is 2 moles of butane on combustion gives −5756 kJ of energy.
You need to take this ratio-
580 g * (1mol C4H10 / 58.12g ) * (−5756 kJ / 2 moles C4H10)
You need to take this ratio-
580 g * (1mol C4H10 / 58.12g ) * (−5756 kJ / 2 moles C4H10)
#77
AP Chemistry / Quiz 6.6 - AP chemistry quiz
Last post by Rayudu - February 01, 2026, 08:13:54 PMNot sure why answer choice C is wrong given my work
#78
AP Chemistry / Re: AP chemistry Question - He...
Last post by uma - January 31, 2026, 07:11:25 AMTo show water and NO as the product
I will take equation 1 as such and will multiply eq 2 with 3/2 and eq3 as such and then add them together
Final equation will be
8NH3 + 13O2 ---> 4NO + 4HNO3 + 10H2O
∆H = -905 -3/2(112)-138 = -1211kJ
Rxn is exothermic
I will take equation 1 as such and will multiply eq 2 with 3/2 and eq3 as such and then add them together
Final equation will be
8NH3 + 13O2 ---> 4NO + 4HNO3 + 10H2O
∆H = -905 -3/2(112)-138 = -1211kJ
Rxn is exothermic
#79
AP Chemistry / Re: AP chemistry Hess's Law
Last post by uma - January 31, 2026, 06:25:21 AMBorn–Haber Cycle Steps:
Sublimation of Mg(s) → Mg(g)→ +150 kJ/mol
1st Ionization: Mg(g) → Mg⁺(g)→ +735 kJ/mol
2nd Ionization: Mg⁺(g) → Mg²⁺(g) → +1445 kJ/mol
Bond dissociation: F₂ → 2 F atoms → +154 kJ/mol
Electron affinity: 2 F(g) → 2 F⁻(g) → 2 × (−328) = −656 kJ/mol
Lattice formation: Mg²⁺ + 2F⁻ → MgF₂(s) → −2913 kJ/mol
Total Enthalpy (ΔHf°):
Δ 𝐻 𝑓∘=
=(150+735+1445+154)−(656+2913)=2484−3569= −1085 kJ/mol
�
Sublimation of Mg(s) → Mg(g)→ +150 kJ/mol
1st Ionization: Mg(g) → Mg⁺(g)→ +735 kJ/mol
2nd Ionization: Mg⁺(g) → Mg²⁺(g) → +1445 kJ/mol
Bond dissociation: F₂ → 2 F atoms → +154 kJ/mol
Electron affinity: 2 F(g) → 2 F⁻(g) → 2 × (−328) = −656 kJ/mol
Lattice formation: Mg²⁺ + 2F⁻ → MgF₂(s) → −2913 kJ/mol
Total Enthalpy (ΔHf°):
Δ 𝐻 𝑓∘=
=(150+735+1445+154)−(656+2913)=2484−3569= −1085 kJ/mol
�
#80
AP Chemistry / AP chemistry Hess's Law -Born–...
Last post by Siba - January 29, 2026, 06:06:37 PMI want practice and a better understanding on how to compute these types of questions.
