Question

level 3 (advanced)
k₂o + h₂o → koh
cr + o₂ → cr₂o₃
cu(no₃)₂ + koh → cu(oh)₂ + kno₃
bacl₂ + na₂so₄ → nacl + baso₄
so₂ + o₂ → so₃
ni + s₈ → ni₂s₃
sc₂o₃ + h₂o → sc(oh)₃

Explanation:

Step1: Balance the first equation

$K_2O + H_2O = 2KOH$

Step2: Balance the second equation

$4Cr+3O_2 = 2Cr_2O_3$

Step3: Balance the third equation

$Cu(NO_3)_2 + 2KOH=Cu(OH)_2 + 2KNO_3$

Step4: Balance the fourth equation

$BaCl_2+Na_2SO_4 = 2NaCl + BaSO_4$

Step5: Balance the fifth equation

$2SO_2+O_2 = 2SO_3$

Step6: Balance the sixth equation

$16Ni + 3S_8=8Ni_2S_3$

Step7: Balance the seventh equation

$Sc_2O_3 + 3H_2O = 2Sc(OH)_3$

Answer:

$K_2O + H_2O = 2KOH$; $4Cr+3O_2 = 2Cr_2O_3$; $Cu(NO_3)_2 + 2KOH=Cu(OH)_2 + 2KNO_3$; $BaCl_2+Na_2SO_4 = 2NaCl + BaSO_4$; $2SO_2+O_2 = 2SO_3$; $16Ni + 3S_8=8Ni_2S_3$; $Sc_2O_3 + 3H_2O = 2Sc(OH)_3$