Chemistry - 9202 OxfordAQA

Chemical Cells And Fuel Cells C

Muhtasari

Somewhere in the room you are sitting in there is almost certainly a small sealed cylinder that is quietly eating itself. A cell in a torch, a remote control or a smoke alarm works by letting one metal corrode on purpose, in a container built so that the electrons released have nowhere to go except the long way round, through your circuit. That is the whole trick of a chemical cell: take a reaction that would otherwise waste its energy as heat, and force the electrons to do a job on their way from one reactant to the other.

It also explains the one thing everybody knows about batteries, which is that they go flat. The reactants are sealed inside, there is a fixed amount of them, and when they run out the voltage collapses. This lesson takes that limit seriously and then shows you the engineering answer to it: a cell you never charge and never throw away, because you pipe the reactants in from outside as fast as it uses them. Hydrogen goes in, air goes in, electricity comes out, and the exhaust pipe drips water.

Malengo

  1. A chemical cell produces a potential difference until the reactants are used up.
  2. Fuel cells produce electricity through the reaction of a fuel with oxygen. Hydrogen-oxygen fuel cells use hydrogen as their fuel, and are useful in cars and spacecraft. Water is the only waste product from a hydrogen-oxygen fuel cell, so they cause less pollution when in use. Students should be able to compare the advantages and disadvantages of the combustion of hydrogen with the use of hydrogen fuel cells from information that is provided. Students should know and understand the benefits and disadvantages of hydrogen fuel in terms of: storage and use; products of combustion. Knowledge of the details of the reactions in fuel cells is not required.

Ramani ya mawazo

Mada hii imechorwa ili uone jinsi mawazo yanavyounganika.

Fungua ramani ya mawazo kwenye programu

Maelezo ya Somo

Drop a strip of magnesium into copper sulfate solution and the magnesium is coated almost at once with a dark spongy deposit of copper, while the solution loses its blue colour. Electrons have moved from magnesium atoms to copper ions, and the energy of that transfer has escaped as warmth in the beaker. Nothing useful has been collected. Now redesign the experiment. Keep the magnesium and the copper apart, put each in contact with a solution that conducts, and join the two metals with a wire. The magnesium still wants to hand its electrons over, but the only route to the copper now runs through your wire. Put a bulb in the way and the bulb lights.

Dokezo Kamili la Somo Linapatikana kwenye Programu ya Green Bridge

Pata programu ya Green Bridge CBT kwenye simu au kompyuta yako kwa maktaba kamili ya IGCSE: mitihani ya miaka iliyopita, miongozo ya usahihishaji, ramani za mawazo, kadi za marudio na masomo ya sauti.

Maelezo kamili ya masomo yenye michoro
Msaidizi wa kujifunza wa AI
Mitihani ya majaribio yenye muda, husahihishwa mara umalizapo
Inapatikana kwa Android, Windows, macOS, na Linux Programu ya iOS inakuja hivi karibuni

Tathmini ya Somo

Hongera kwa kukamilisha somo la Chemical Cells And Fuel Cells C. Sasa kwa kuwa umechunguza dhana na mawazo muhimu, ni wakati wa kuweka ujuzi wako kwa mtihani. Sehemu hii inatoa mazoezi mbalimbali maswali yaliyoundwa ili kuimarisha uelewaji wako na kukusaidia kupima ufahamu wako wa nyenzo.

Utakutana na mchanganyiko wa aina mbalimbali za maswali, ikiwemo maswali ya kuchagua jibu sahihi, maswali ya majibu mafupi, na maswali ya insha. Kila swali limebuniwa kwa umakini ili kupima vipengele tofauti vya maarifa yako na ujuzi wa kufikiri kwa makini.

Tumia sehemu hii ya tathmini kama fursa ya kuimarisha uelewa wako wa mada na kubaini maeneo yoyote ambapo unaweza kuhitaji kusoma zaidi. Usikatishwe tamaa na changamoto zozote utakazokutana nazo; badala yake, zitazame kama fursa za kukua na kuboresha.

  1. A simple chemical cell is made from two metal strips dipping into an electrolyte. Which change would produce the largest potential difference? A. Using two strips of the same metal B. Using two metals that are close together in the reactivity series C. Using two metals that are far apart in the reactivity series D. Using larger strips of the same two metals Answer: C
  2. Why does a non-rechargeable chemical cell eventually stop producing a potential difference? A. The electrons in the wire are used up. B. The reactants inside the cell are used up. C. The electrolyte cools down. D. The electrodes become the same metal. Answer: B
  3. Which substance is the only product of the reaction in a hydrogen-oxygen fuel cell? A. Carbon dioxide B. Hydrogen peroxide C. Water D. Oxides of nitrogen Answer: C
  4. Which statement explains the main difference between a fuel cell and an ordinary chemical cell? A. A fuel cell contains no electrolyte. B. A fuel cell has electrodes made of the same metal. C. A fuel cell has its reactants supplied continuously from outside. D. A fuel cell produces heat rather than a potential difference. Answer: C
  5. Which of these is a disadvantage of using hydrogen as a fuel in a car? A. Burning it produces carbon dioxide. B. It is difficult to store because it is a gas of very low density at ordinary temperatures. C. It cannot be made from water. D. It releases no energy when it reacts with oxygen. Answer: B

Fanyia kazi maswali haya kwenye programu

Fanyia kazi maswali haya kwenye programu

Fanya Mazoezi ya Maswali ya Majaribio

Ungependa kufanya mazoezi ya maswali ya majaribio kuhusu Chemical Cells And Fuel Cells C? Pakua programu ya Green Bridge CBT ili kupata maswali ya majaribio na tathmini kamili za mazoezi kuhusu mada hii.

Pakua Programu Kwenye Google Playstore

Kila kitu unachohitaji ili kufaulu katika JAMB, WAEC & NECO.

Green Bridge CBT Mobile App
Msaidizi wa Gumzo wa Kujifunza wa AI Uliobinafsishwa
Maswali ya mtihani zaidi ya 200,000 ya IGCSE, JAMB, WAEC na NECO
Zaidi ya Madaftari ya Masomo 1200
Msaada Nje ya Mtandao - Jifunze Wakati Wowote, Popote Pale
Ratiba ya Daraja la Kijani
Muhtasari wa Fasihi na Maswali Yanayoweza Kutokea
Fuata Utendaji na Maendeleo Yako
Maelezo ya Kina kwa Kujifunza kwa Kina