7. How many H_(2) molecules are needed to make 4.00 moles of water in the following equation? 2H_(2)+O_(2)arrow 2H_(2)O 2.41times 10^24 E 12.04times 10^23 E 6.02times 10^23 4.82times 10^24 E Clear All

To determine how many $H_{2}$ molecules are needed to make 4.00 moles of water, we need to use the balanced chemical equation:<br /><br />$2H_{2} + O_{2} \rightarrow 2H_{2}O$<br /><br />From the equation, we can see that 2 moles of $H_{2}$ are required to produce 2 moles of $H_{2}O$. Therefore, the ratio of $H_{2}$ to $H_{2}O$ is 1:1.<br /><br />Given that we have 4.00 moles of $H_{2}O$, we can calculate the number of moles of $H_{2}$ needed:<br /><br />Number of moles of $H_{2}$ = 4.00 moles of $H_{2}O$<br /><br />Now, we need to convert the number of moles of $H_{2}$ to the number of molecules. We can use Avogadro's number, which is $6.022 \times 10^{23}$ molecules per mole.<br /><br />Number of molecules of $H_{2}$ = 4.00 moles of $H_{2} \times 6.022 \times 10^{23}$ molecules/mole<br /><br />Calculating this gives us:<br /><br />Number of molecules of $H_{2}$ = $2.41 \times 10^{24}$ molecules<br /><br />Therefore, the correct answer is $2.41 \times 10^{24}$ molecules of $H_{2}$ are needed to make 4.00 moles of water.