Chapter 1 Chemical Equations And Reactions

During the electrolysis of water, the decomposition reaction occurs, resulting in the liberation of hydrogen and oxygen gases. The mole ratio refers to the ratio of the number of moles of one substance to another in a chemical reaction. In this case, the mole ratio of hydrogen to oxygen gases liberated during the electrolysis of water is 2:1. This means that for every 2 moles of hydrogen gas produced, 1 mole of oxygen gas is also produced.

When element X (fe) is exposed to moist air, it undergoes a chemical reaction and turns reddish brown. This indicates the formation of a new compound Y (fe2O3), which is iron(III) oxide. Iron(III) oxide is commonly known as rust and is formed when iron reacts with oxygen in the presence of moisture. Therefore, the correct answer is X=fe, Y=fe2O3.

In the given equation, Cu reacts with HNO3 to form Cu(NO3)2, NO2, and H2O. The balanced equation shows that for every 1 mole of Cu, 4 moles of HNO3 are required. This means that x must be equal to 4. Additionally, the equation shows that for every 1 mole of Cu, 2 moles of NO2 are produced. This means that y must be equal to 2. Therefore, the values of x and y are 4 and 2, respectively.

Storing the food in air tight containers and storing the food in the refrigerator both help to prevent the food from getting rancid by limiting exposure to air and controlling the temperature. However, keeping the food in clean and covered containers and always touching the food with clean hands do not directly prevent the food from getting rancid. These practices are important for maintaining hygiene and preventing contamination, but they do not specifically address the issue of food rancidity.

In a reaction between sulphuric acid and barium chloride solution, a white precipitate is formed. This white precipitate is known as barium sulphate.

When copper powder is heated, it undergoes a chemical reaction with oxygen in the air, resulting in the formation of black copper oxide. This black coating is a result of the copper atoms combining with oxygen atoms to form copper oxide. This reaction is commonly known as oxidation and is responsible for the black color observed on the surface of the copper powder.

Nitrogen is used in the storage of fat and containing foods for a long time because it is an inert gas. It helps to create a controlled environment by displacing oxygen, which slows down the oxidation process and prevents the growth of bacteria and other microorganisms. This helps to extend the shelf life of the food and maintain its quality for a longer period of time.

A reducing agent is a substance that donates electrons to another substance, causing it to be reduced. In this case, the substance oxidizes itself by losing electrons and at the same time reduces another substance by donating those electrons. Therefore, the correct answer is reducing agent.

Black and white photography uses both the decomposition of silver chloride and the decomposition of silver bromide. In traditional black and white film photography, silver halide crystals (such as silver chloride or silver bromide) are used to capture light and create an image. When exposed to light, these crystals undergo a chemical reaction called decomposition, which forms metallic silver particles. These silver particles are then developed and fixed onto the film, resulting in a black and white image. Therefore, both silver chloride and silver bromide are used in the process of black and white photography.

A combination of phosphorus and oxygen is an example of an oxidation reaction because oxidation involves the loss of electrons or an increase in the oxidation state of an element. In this case, phosphorus is being oxidized as it gains oxygen atoms and increases its oxidation state.