A common way to make hydrogen gas in the laboratory is to place a metal such as zinc in hydrochloric acid (see the figure). The hydrochloric acid reacts with the metal to produce hydrogen gas, which is then collected over water. Suppose a student carries out this reaction and collects a total of 144.8 mL of gas at a pressure of 749 mmHg and a temperature of 25âC. What mass of hydrogen gas (in milligrams) does the student collect? (The vapor pressure of water is 23.78 mmHg at 25âC.)
Express the mass to three significant figures and include the appropriate uni
Collecting a Gas over Water Zn HCl. Hydrogen plus water vapor H2O
