Science Class X: Case Studies on Marble and Reactions

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Questions and Answers

What type of chemical reaction primarily occurs during the combustion of fuel?

Oxidation & Exothermic reaction

Why do incomplete combustion reactions produce black smoke?

Limited supply of air leads to incomplete combustion of fuel.

How is nitrogen's role in combustion described?

Nitrogen is an inert gas.

Identify two processes that are similar to combustion based on energy changes.

Photosynthesis in plants and respiration in the human body. Signup and view all the answers

What happens to aquatic life in the Yamuna due to high pollution levels?

The pollution has led to parts of the river being labeled 'dead' due to lack of oxygen. Signup and view all the answers

What is the primary source of phosphates causing frothing in the Yamuna?

Wastewater from detergents used in dyeing industries and households. Signup and view all the answers

In the context of chemical reactions, what is the significance of exothermic reactions?

Exothermic reactions release energy, often in the form of heat. Signup and view all the answers

What two gases are commonly produced as a by-product of fuel combustion?

Carbon dioxide (CO2) and water vapor (H2O). Signup and view all the answers

What type of reaction occurs between MnO2 and HCl?

redox reaction Signup and view all the answers

Chlorine gas reacts with which substance to form bleaching powder?

dry Ca(OH)2 Signup and view all the answers

What happens to MnO2 during its reaction with HCl?

MnO2 is getting reduced whereas HCl is getting oxidized. Signup and view all the answers

What is the nature of MnO2 in chemical terms?

Basic oxide Signup and view all the answers

What effect does using dry HCl gas instead of aqueous HCl have on the reaction with MnO2?

Reaction will not occur. Signup and view all the answers

What is a primary role of the distributor and battery in an internal combustion engine?

They provide the starting energy by creating an electrical spark. Signup and view all the answers

What are the products obtained from the complete combustion of gasoline?

Carbon dioxide and water Signup and view all the answers

What is necessary for the complete combustion of gasoline to take place?

Full supply of air Signup and view all the answers

What is the likely chemical formula for marble, which is primarily composed of calcium carbonate?

CaCO3 Signup and view all the answers

In a chemical reaction, what happens to calcium carbonate when it decomposes due to heating?

It forms calcium oxide and carbon dioxide. Signup and view all the answers

Why does marble corrode or stain when exposed to acidic rainwater?

It reacts with the acidic water, leading to the dissolution of calcium carbonate. Signup and view all the answers

Which process is identified as the biochemical process that involves gas A produced from calcium carbonate decomposition?

Photosynthesis Signup and view all the answers

What acts as an oxidizing agent when calcium oxide is reduced to calcium using sodium metal?

Calcium oxide Signup and view all the answers

If calcined gypsum is added to the options regarding CaCO3 sources, why is it deemed unlikely to contain it?

Calcined gypsum is primarily calcium sulfate. Signup and view all the answers

What is the primary difference between the decomposition of calcium carbonate and its reaction with acids?

Decomposition produces CAO and CO2, while reaction with acids produces salt, water, and CO2. Signup and view all the answers

In the context of chemical reactions, what role does MnO2 play when reacting with HCl?

MnO2 acts as an oxidizing agent. Signup and view all the answers

Study Notes

Science - Class X - Sample Case Studies

Marble's popularity: Began in ancient Rome and Greece, used for structures (sculptures, pillars, buildings).
CaCO3 Content: Dolomite, marble statues, and sea shells likely contain CaCO3; calcined gypsum is not.
Calcium Carbonate Decomposition: A student heated 10g of calcium carbonate in a rigid container. Pressure increased over time. Maximum decomposition occurred between 0 and 5 minutes (based on provided graph).
Gas A: Gas A, produced by the decomposition, is a reactant in photosynthesis (a crucial biochemical process requiring sunlight)
Marble Corrosion: Pollution in rainwater (acidic) causes corrosion of marble statues, stemming from the reaction between the acidic water and calcium carbonate.
MnO2 + HCl Reaction: A redox reaction forms a gas with bleaching properties when manganese(IV) oxide (MnO2) reacts with hydrochloric acid (HCl).
Chlorine Gas Reaction: Chlorine gas reacts with dry calcium hydroxide (Ca(OH)2) to form bleaching powder.
Nature of MnO2: Manganese(IV) oxide is a basic oxide.
HCl Gas Reaction: Dry Hydrogen chloride will not react with manganese oxide (MnO2).
Automobile Chemistry: Complete combustion of octane (a component of gasoline) in the presence of oxygen produces carbon dioxide (CO2) and water (H2O).
Combustion Types: Combustion is an exothermic oxidation reaction.
Processes similar to combustion: Photosynthesis and respiration in living organisms, in terms of their roles in energy conversion and use
Factors affecting combustion: Limited air supply leads to incomplete combustion, which produces black smoke.
Nitrogen in combustion: Nitrogen does not participate in combustion because it's an inert gas (doesn't react under most conditions).
Yamuna River Foam: High phosphate content in wastewater from detergents and other sources leads to foam formation in the river.
Yamuna Water Quality: Phosphate pollution dangerously degrades the river's water quality, with no oxygen to sustain aquatic life.
pH of Yamuna Water: Detergents in the water lead to a high pH (alkaline) in Yamuna.
Phosphate in River Yamuna: High phosphate levels affect the river. This can cause increased growth of algae and a decrease in dissolved oxygen, ultimately affecting the aquatic ecosystem's biodiversity.
Wastewater Treatment: Using baking soda is one method to reduce the detrimental effects of detergents in water.
Biogas Plant Components: Biogas plants use anaerobic bacteria (in areas without air) to convert matter into energy - these areas are called digesters.
Biogas Composition: Biogas is primarily methane (CH4), along with carbon dioxide (CO2), and other gases.
Biogas Sources: Mostly generated from organic matter like animal manure and domestic waste.
Biogas Benefits: A renewable energy source and a way to deal with waste product. It's better than animal dung cake due to its high heating capacity and ability to burn without producing smoke.
Food Chains: Essential for species survival, with producers at the base, followed by primary and secondary consumers, and finally decomposers.
Food Chain Energy Transfer: Only about 10% of the energy is transferred from one level of a food chain to the next.
Food Webs: Food webs show interconnected food chains, showcasing the complex feeding relationships within an ecosystem.
Trophic Levels: Organisms are categorized within trophic levels (producer, primary consumer, secondary consumer, decomposer) based on their role in the food chain.
Reasons for the number of trophic levels in a food chain: Reduction in energy at higher levels of the food chain.
Why food chains start with plants: Green plants produce their food using solar energy (photosynthesis).
Competition in food webs: Animals or microorganisms may compete for similar food sources, like the example given of competing organisms in the food web.
Waste Management Strategies: The '5 Rs' (Refuse, Reduce, Reuse, Repurpose, Recycle) are crucial for managing waste effectively.
Waste Composition Data: Waste data for percentages of waste that are dumped, treated, or are not processed accurately is given.

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Description

Explore various case studies related to marble and chemical reactions in this Class X science quiz. Learn about the historical significance of marble, the chemistry behind calcium carbonate, and the impacts of pollution on marble statues. Test your understanding of reactions involving gases and their implications in environmental science.