Question

The thermochemical equation for the reaction is shown below:

4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s) ΔH = -3352 kJ

How much heat is released when 8.07 g of Al react with O₂(g) at 25 ^oC and 1 atm?

Select the oxidation-reduction reaction(s)?

1. Cl₂(g) +   ZnBr₂(aq) → ZnCl₂(aq) + Br₂(l)

2. Pb(ClO₄)₂(aq) + 2 KI(aq) → PbI₂(s) + 2 KClO₄(aq)

3. CaCO₃(s) → CO₂(g) + CaO(s)

Select the strong acid in aqueous solution from the set below.

Group of answer choices

CH₃OH

HNO₂

HF

HBr

A 77.0-mL sample of a 0.203 M potassium sulfate solution is mixed with 55.0 mL of a 0.226 M lead(II) nitrate solution and this reaction occurs:

K₂SO₄(aq) + Pb(NO₃)₂ (aq)   

⟶⟶

⟶⟶ 2 KNO₃(aq) + PbSO₄(s)

The solid PbSO₄ is collected, dried, and found to have a mass of 2.62 g. Determine the percent yield. 1 mole PbSO₄ = 303.26 g

Answer 1

Ans: - UH=-3352 KJ 4 Alcs + 30209) → 2 A1,03C5) INUIT Limol Al react o, and heat is released = -3352 KJ Imol Al react o, and heat is released = -838 KJ Al react o, and heat is rebused: -838 kJ 279m. 27 19.m. Al react Oz and heat is released : -838 KJ = 31.04 KJ 8.079 Al react Oz and heat is released - 8.07X31.04 kJ = -250-4928 kJ Ans:- Pb CClO4)24) + 2 khaº) – PbIz(s) + 2kCloy cae) +2 -1 +1 -1 -2 + -1 +2 -1 -2 3 CaCO₃ 7 CO2(g) + Cao +2 -2 4-2 +2 -2 4 - 2 cle + Zn B8 ZnCl2 + Bra Call +2 -1 +2 -1 0 Reduction Cl → ZnCl2 oxidation ZnBх, — Ba, So 1 is correct option

Ang- HBr is strong acid HF (Pka) = 3.1 HBO (Pka)=-90 CH2OH(PK) = 15.54 HNOZCPkq) = 3.15 means Less pka valuea moze acidity