Hi Mai,

Thanks for your message and for inviting me to your house. I'm free on Sunday and will be happy to visit you. It's great that you find my cookbook useful and like the recipes there. I've tried some of the main dishes and they are delicious. So what time shall I come to your place? It might be a good idea to do the cooking in the morning, before lunch. I'll definitely bring some fresh mangos from our garden. We have so many, and they are all ripe and ready for eating. Did you know that mangos are a great source of vitamins A, B and C?Do you want me to bring anything else? I can also go to the supermarket or the farmers' market to buy other cooking ingredients. Just let me know.

See you soon,

Linda

a. pương trình cân bằng: 
5CaC2​O4​+2KMnO4​+8H2​SO4​→5CaSO4​+2MnSO4​+K2​SO4​+10CO2​+8H2​O

b.0,1003mg×100=10,03mg Ca2+/100mL máu

a.  Fe: là chất khừ    

    N: là chất ôxh                                     Cân bằng:   Fe + 4 HNO₃ → Fe(NO₃)₃ + NO + 2 H₂O

    quá trình oxh: Fe⁰ -> Fe⁺³+3e  | x1

     quá trình khử:N⁺⁵+3e-> N^{+2     |  x1}

b. Fe: là chất khử                                                Cân bằng:    

     Mn: là chất oxh                                                                     2 KMnO₄ + 10 FeSO₄ + 8 H₂SO₄ → 5 Fe₂(SO₄)₃ + 2 MnSO₄ + K₂SO₄ + 8 H₂O

     quá trình oxh: Fe⁺² -> Fe⁺³ +1e       | x5

      quá trình khử: Mn⁺⁷ + 5e -> Mn^{+2    | x1}

Δr​H298∘​=[(−542,83)+2×(−167,16)]−(−795,0) $$=[-542,83-334,32]+795,0=[-877,15]+795,0=-82,15\text{kJ/mol Vậy đây là phản ứng tỏa nhiệt}$$