Which of these reactions are redox reactions? check all that apply.

cd + hcl → cdcl2 + h2

cucl2 + na2s → 2nacl + cus

caco3 → cao + co2

2zns + 3o2 → 2zno + 2so2

ch4 + 2o2 → co2 + 2h2o

 The  reaction  that  are   redox  reaction  are

 Cd  +HCl  →  CdCl2  +H2

2 ZnS  +3 O2→ 2 ZnO  + 2  SO2

CH4  +2O2→ CO2 + 2 H2O

Explanation

A  redox  reaction is a  type of  reaction  which involve  both  reduction  and  oxidation.

Cd +HCl → CdCl2 +H2  is a redox  equation  because

 Cd is  oxidized   from  oxidation state   0 to  2+  while H  is  reduced from oxidation state  1 t o 0

All combustion reaction   are redox reaction  therefore

2 ZnS  + 3 O2 → 2ZnO + 2 SO2

    and

CH4 +2 O2 →  CO2 + 2 H2O  are  redox reaction

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

they are both synthetic elements

explanation:

d