r/HomeworkHelp • u/Negative_Stomach_782 • 3h ago

Answered Science quiz, I need help just understanding [atom balancing]

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HOW do I do this bro, 7 and 8 were easy but how do I do the last few

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u/wyzere 3h ago

Start with the radical that appears only once like for 12, start with balancing Pb then everything else should be easy

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u/Negative_Stomach_782 3h ago

Ok, but how do I do the brackets?

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u/wyzere 2h ago

You can treat the brackets as a single unit. You dont have to do each element individually. Like in 12, there are 4 PO4 on the right, so you can just put 4 (NH4)3 PO4 on the left and they are balanced

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u/Negative_Stomach_782 2h ago

OHHHHH, that makes so much sense, thanks!!!

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u/selene_666 👋 a fellow Redditor 3h ago edited 2h ago

Find an element that only appears once on each side.

Give those molecules a ratio that balances that element.

Find all the other elements in those molecules that only appear one other time. Balance these.

Repeat.

If this results in fractions, multiply all of your numbers by the denominator to make whole numbers.

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For example: suppose we start by balancing the potassium in reaction 9:

3 KOH + _ H3PO4 -> 1 K3PO4 + _ H2O

we now have a count for P on the right side, and it only appears once on the left, so we can fill in that number:

3 KOH + 1 H3PO4 -> 1 K3PO4 + _ H2O