+2 3H₂2₂)= Exercise 4. In the hydrogen economy, the production of H₂ is based on solar energy and the hydrogen - gas can then be used as fuel: gi 67het 572 2H₂(g) + O₂(g) -> 2 H₂O (1) 34.30:57 15/mal An important advantage of hydrogen as a fuel is that it does not cause pollution. A major disadvantage, however, is that it is a gas and is therefore much more difficult to store than a liquid or solid. Calculate the required volume of hydrogen gas at 25°C and 1 atm to provide as much energy as the combustion of 1 liter octane (C8H18). The density of octane is 0.7 kg/l and AH = -249.9 kJ/mol. [2659 liter]

The Apollo 13 mission astronauts are running out of oxygen and need to get rid of the excess carbon dioxide. You know that sodium hydroxide can remove carbon dioxide from the spacecraft cabin. The filter which they had been using is fully saturated and no longer works. The astronauts have a 5 kg container of sodium hydroxide on the ship. The reaction to neutralize the air, remove carbon dioxide with sodium hydroxide is shown below CO2(g) + 2NaOH(s) ⟶⟶ Na2CO3(aq) + H2O(l)   The astronauts have 2 days left before they land on earth. You know that there are three astronauts, and each astronaut emits roughly 500. g of carbon dioxide each day. Is there enough sodium hydroxide in the cabin to cleanse the cabin air of the carbon dioxide, or are the astronauts doomed? Calculate how much sodium hydroxide is required to remove all the carbon dioxide from the three astronauts.  Be sure to show all your work!

Consider the reaction. heat 2 Al(s) + Fe,0,(s) Al, 0,(s) + 2 Fe(1) If 10.7 kg Al reacts with an excess of Fe, O3, how many kilograms of Al,O, will be produced? mass of Al, O, produced: kg * TOOLS x10

||| O Microsoft O The useful metal manganese can be extracted from the mineral rhodochrosite by a two-step process. In the first step, manganese(II) carbonate and oxygen react to form manganese(IV) oxide and carbon dioxide: 2MnCO3(s) + O₂(g) 2MnO₂ (s) + 2 CO₂(g) W O CHEMICAL REACTIONS Reaction sequence stoichiometry In the second step, manganese (IV) oxide and aluminum react to form manganese and aluminum oxidide: 3 MnO₂ (s) + 4A1(s)→ 3Mn(s) + 2 Al₂O₂ (s) Microsoft esc Suppose the yield of the first step is 73.% and the yield of the second step is 86.%. Calculate the mass of manganese(II) carbonate required to make 1.0 kg of manganese. Be sure your answer has a unit symbol, if needed, and is rounded to the correct number of significant digits. G Microsoft 6.52.210... Explanation B ! Check 9,270 280 103 x10 HE X OCT 24 ロ・ロ Ś III E % LC ustv ♫ 6 2 & 7 9 © 2022 McGraw Hill LLC. All Rights Reserved. Terms of Use | Privacy Center | Accessibility DZA 8 9 1/5 W 0 30 Simrat V + 11 ? olo Ar 2…

The great French chemist Antoine Lavoisier discovered the Law of Conservation of Mass in part by doing a famous experiment in 1775. In this experiment Lavoisier found that mercury(II) oxide, when heated, decomposed into liquid mercury and an invisible and previously unknown substance: oxygen gas. 1. Write a balanced chemical equation, including physical state symbols, for the decomposition of solid mercury(II) oxide (HgO) into liquid mercury and gaseous dioxygen. 2. Suppose 71.0 mL of dioxygen gas are produced by this reaction, at a temperature of 50.0 °C and pressure of exactly 1 atm. Calculate the mass of mercury(II) oxide that must have reacted. Be sure your answer has the correct number of significant digits.

Phosphoric acid, which is commonly used as rust inhibitor, food additive and etching agent for dental and orthopedic use, can be synthesized using a two-step thermal process. In the first step, phosphorus and oxygen react to form diphosphorus pentoxide: P4(1)+50₂(9) 2 P₂05(9) In the second step, diphosphorus pentoxide and water react to form phosphoric acid: P₂O(g) + 3 H₂O(1)-2H₂PO4(1) ob Write the net chemical equation for the production of phosphoric acid from phosphorus, oxygen and water. Be sure your equation is balanced. XS 2