Question

hydrogen peroxide can be used to disinfect and clean surfaces around the home. it breaks down over time into oxygen gas and water. consider the following reaction: some amount of hydrogen peroxide (h₂o₂) breaks down to produce 3 molecules of oxygen (o₂) and 6 molecules of water (h₂o). complete the table below. \
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chemical element	number of atoms in the reaction	\
------------------	---------------------------------	\
h	\\u25a1 \\u25a1	\
o	\\u25a1	\

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during this reaction, how many molecules of hydrogen peroxide (h₂o₂) react? \
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work it out\
not feeling ready yet? this can help: \
count atoms and molecules in chemical reactions (1:05) link

Explanation:

For the number of H atoms:

Step1: Calculate H from H₂O

Each H₂O has 2 H atoms, and there are 6 H₂O molecules. So H from H₂O: \( 2\times6 = 12 \). Since H only comes from H₂O (as O₂ has no H), total H atoms: \( 12 \).

Step2: Calculate O atoms

• From O₂: Each O₂ has 2 O atoms, 3 O₂ molecules: \( 2\times3 = 6 \).
• From H₂O: Each H₂O has 1 O atom, 6 H₂O molecules: \( 1\times6 = 6 \).
• Total O atoms: \( 6 + 6 = 12 \).

For the number of H₂O₂ molecules:

Step3: Use H atoms to find H₂O₂

Each H₂O₂ has 2 H atoms. Let \( x \) be the number of H₂O₂ molecules. Total H atoms from H₂O₂: \( 2x \). We know total H atoms are 12, so \( 2x = 12 \), solving for \( x \): \( x = \frac{12}{2} = 6 \). Or check O: Each H₂O₂ has 2 O atoms, total O from H₂O₂ should be 12 (from earlier), so \( 2x = 12 \), \( x = 6 \).

Answer:

s:

• Number of H atoms: \( 12 \)
• Number of O atoms: \( 12 \)
• Number of H₂O₂ molecules: \( 6 \)