Calcium hydride (CaH 2) reacts with water to form hydrogen gas: CaH 2 (s) + 2H 20 (1)→ Ca(OH) 2 (aq) + 2H 2 (g) How many grams of CaH 2 are needed to generate 12.4 L of H 2 gas at a pressure of 0.934 atm and a temperature of 23°C? (Molar Mass of CaH 2=42.09 g) O 10.0 O 8.25 O 11.6 O 14.2 O 6.23

A 0.477 mol sample of O2 gas has a volume of 10.0 L at a certain temperature and pressure. If all this O₂ were converted to ozone (03) at the same temperature and pressure, what is the ozone volume (in liters)? 3 02(g) → 2 03(g)

A gas phase reaction occurs in a syringe at constant temperature and pressure. If the initial volume in the syringe is 12.3 mL and the final volume is 4.1 mL, which of the following general reactions could have occurred? a) A(g) + B(g) → AB(g) b) 2A(g) + B(g) → A2B(g) c) 2AB(g) → A2(g) + 2B(g) d) 2AB (g) → A2(g) + B2(g) e) 2A2(g) + 4B(g) → 4AB(g) a e

2 H3PO4(s) --> 3 H2(g) + 2 P(s) + 4 O2(g) Using the reaction above, show step by step how many liters of oxygen can be created if I start with 0.7156 grams of H3PO4 solid at STP?

According to the balanced equation, how many grams of aluminum are necessary to produce 1.50 Liters of hydrogen gas at STP? 2 Al(s) + 6 HCl(aq) --> 2 AlCl3(aq) + 3 H2(g)

Please answer questions 1-3 Please refer to the picture below:

A student experimentally determines the gas law constant, R, by reacting a small piece of magnesium with excess hydrochloric acid and then collecting the hydrogen gas over water in a eudiometer. Based L-atm on experimentally collected data, the student calculates R to equal 0.0832 mol·K L-atm Ideal gas law constant from literature: 0.08206 mol·K (a) Determine the percent error for the student's R-value. Percent error = % (b) For the statements below, identify the possible source(s) of error for this student's trial. The student notices a large air bubble in the eudiometer after collecting the hydrogen gas, but does not dislodge it. The student does not clean the zinc metal with sand paper. The student does not equilibrate the water levels within the eudiometer and the beaker at the end of the reaction. The water level in the eudiometer is 1-inch above the water level in the beaker. The student uses the barometric pressure for the lab to calculate R.

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Hydrogen gas can be prepared by the reaction of zinc metal with dilute aqueous hydrochloric acid: Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) How many moles of hydrogen would be produced in the reaction if 7.90 g of zinc reacts?  What volume of H2 would be produced in this reaction under standard conditions (25°C and 1.013 x 105 Pa)?

Given that the concentration of CH4 in the atmosphere is 1.8 ppm, calculate the total mass of this gas that is present in the atmosphere. Note that the total mass of the atmosphere is 5.1 x 1018 kg and that its average molar mass is 29.0 g/mol.