Đáp án: 4:7:2:4
Giải thích các bước giải:
4FeS+7O2→2Fe2O3+4SO2
4FeS+ 12O2 -->2 Fe2O3 + 4SO4
Choose the best answer.
I think you should buy _____ pack of mineral water instead. And you can also buy _____ snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ______ cookies and soft candies.
We should decorate our living room with _____ orange banner. We also need ________ ribbons, balloons, party hats and costume.
I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.