Do the given work,Submit on paper to your teacher. 1. Some potassium oxide was placed in 9 grams of water, and 112 grams of potassium hydroxide were made. What mass of potassium oxide was used? 2. 15 grams of magnesium reacted with oxygen to produce 25 grams of magnesium oxide. What mass of oxygen was used? 3. When 50 grams of sodium chloride reacted with 10 grams of silver nitrate, 35 grams of silver chloride and some sodium nitrate were formed. What mass of sodium nitrate was produced? 4. A student burns 120 grams of carbon in oxygen to produce 440 grams of carbon dioxide. What mass of oxygen was used in the reaction? 5. If 8 grams of hydrogen react with 64 grams of oxygen , how many grams of water will be produced?

1. To find the mass of potassium oxide used, we can use the law of conservation of mass, which states that the total mass of the reactants must equal the total mass of the products. In this case, the total mass of the products is 112 grams of potassium hydroxide. Since the mass of water is given as 9 grams, the mass of potassium oxide can be calculated as follows:<br /><br />Mass of potassium oxide = Total mass of products - Mass of water<br />Mass of potassium oxide = 112 grams - 9 grams<br />Mass of potassium oxide = 103 grams<br /><br />Therefore, 103 grams of potassium oxide were used.<br /><br />2. To find the mass of oxygen used, we can again use the law of conservation of mass. The total mass of the products is 25 grams of magnesium oxide, and the mass of magnesium is given as 15 grams. Therefore, the mass of oxygen can be calculated as follows:<br /><br />Mass of oxygen = Total mass of products - Mass of magnesium<br />Mass of oxygen = 25 grams - 15 grams<br />Mass of oxygen = 10 grams<br /><br />Therefore, 10 grams of oxygen were used.<br /><br />3. To find the mass of sodium nitrate produced, we can use the law of conservation of mass. The total mass of the reactants is 50 grams of sodium chloride + 10 grams of silver nitrate = 60 grams. The total mass of the products is 35 grams of silver chloride + Mass of sodium nitrate. Therefore, the mass of sodium nitrate can be calculated as follows:<br /><br />Mass of sodium nitrate = Total mass of reactants - Total mass of products<br />Mass of sodium nitrate = 60 grams - 35 grams<br />Mass of sodium nitrate = 25 grams<br /><br />Therefore, 25 grams of sodium nitrate were produced.<br /><br />4. To find the mass of oxygen used in the reaction, we can use the law of conservation of mass. The total mass of the products is 440 grams of carbon dioxide, and the mass of carbon is given as 120 grams. Therefore, the mass of oxygen can be calculated as follows:<br /><br />Mass of oxygen = Total mass of products - Mass of carbon<br />Mass of oxygen = 440 grams - 120 grams<br />Mass of oxygen = 320 grams<br /><br />Therefore, 320 grams of oxygen were used in the reaction.<br /><br />5. To find the mass of water produced, we the law of conservation of mass. The total mass of the reactants is 8 grams of hydrogen + 64 grams of oxygen = 72 grams. Therefore, the mass of water produced can be calculated as follows:<br /><br />Mass of water = Total mass of reactants<br />Mass of water = 72 grams<br /><br />Therefore, 72 grams of water will be produced.