Question

All faculty members are happy to see students help each other. Dumbledore is particularly pleased with Hermione. Though, it should be mentioned that students should not simply copy off each other. You will not learn anything that way. Snape glares at Ron... Ron slouches in his chair. Snape thinks it’s time for a harder problem. How many milligrams of magnesium reacts with excess HCl to produce 31.2 mL of hydrogen gas at 754 Torr and 25.0◦C. The hydrogen is produced by the following reaction: Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) Express your answer in milligrams

Answer 1

Answer:

$m_{Mg}=30.8mgMg$

Explanation:

Hello,

Based on the given chemical reaction, as 31.2 mL of hydrogen are yielded, one computes its moles via the ideal gas equation under the stated conditions as shown below:

$n_{H_2}=\frac{PV}{RT}=\frac{754torr*\frac{1atm}{760torr}*0.0312L}{0.082 \frac{atm*L}{mol*K}*298.15K}=1.27x10^{-3}molH_2$

Now, since the relationship between hydrogen and magnesium is 1 to 1, one computes its milligrams by following the shown below proportional factor development:

$m_{Mg}=1.27x10^{-3}molH_2*\frac{1molMg}{1molH_2}*\frac{24.305gMg}{1molMg}*\frac{1000mgMg}{1gMg}\\m_{Mg}=30.8mgMg$

Best regards.