Energy From Fuels

விளையாடிக் கற்றுக்கொள்ளுங்கள்

ஆற்றல் சம்பாதிக்க இந்த கேள்விகளுக்குப் பதிலளியுங்கள், பின்னர் மீன் பிடித்து ஆராயுங்கள். கணக்கு தேவையில்லை.

கல்வியாளர்களுக்கு: Energy From Fuels (Chemistry, HL)-க்கான தயாரான பாட ஸ்லைடுகள், திருப்புதல் குறிப்புகள் — உங்கள் பாடத்தில் அவற்றைப் பயன்படுத்தவும், அல்லது கற்பவர்கள் நேரலை விளையாட்டாக விளையாடும் ஊடாடும் வகுப்பு செயல்பாடாக தலைப்பை இயக்கவும்.

பாட குறிப்புகள்

Combustion Reactions

Combustion is a rapid, exothermic reaction involving a fuel, oxygen (it is a type of oxidation) and an ignition source such as a spark, flame or heat build-up.
It is commonly called burning and releases heat and light.
There are two main types: complete combustion (with sufficient oxygen) and incomplete combustion (limited oxygen).
All metals oxidise, but not all combust; some only burn if finely divided as powders or filings with a high surface area.
Less reactive metals such as copper do not combust but do oxidise, forming black copper oxide on heating.
More reactive metals such as magnesium combust in air with a bright white flame: 2Mg (s) + O₂ (g) → 2MgO (s).
The general word equation for metal combustion is: metal + oxygen → metal oxide; the oxides of s-block metals are ionic and basic (pH > 7 in water).
Many non-metals form covalent oxides that are usually acidic (pH < 7 in water); e.g. sulfur burns with a blue flame: S (s) + O₂ (g) → SO₂ (g).

Complete Combustion of Organic Compounds

Organic fuels such as hydrocarbons (especially alkanes) and alcohols release large amounts of energy when combusted.
They do not spontaneously combust because their reactions have a high activation energy, making them easy and safe to transport and store.
In excess oxygen, complete combustion occurs: all carbon and hydrogen are oxidised, giving carbon dioxide and water.
Word equation: fuel + oxygen → carbon dioxide + water.
Example: CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l).
Alcohols also undergo complete combustion: C₂H₅OH (l) + 3O₂ (g) → 2CO₂ (g) + 3H₂O (l).
When balancing alcohol combustion equations, remember to count the oxygen atom already present in the alcohol.
Lower alcohols like ethanol burn with an almost invisible flame; blending ethanol with gasoline or diesel increases energy density and makes flames more visible for safety.

Incomplete Combustion

Incomplete combustion occurs when oxygen is limited; it still produces water from the hydrogen in the fuel.
Carbon is not fully oxidised, so the products include carbon monoxide (CO) or carbon (C).
It is common in car engines and faulty boilers where the oxygen supply is restricted.
In a Bunsen burner, complete combustion gives a blue, non-luminous flame; incomplete combustion gives a yellow, luminous flame.
With limited oxygen, CO forms: e.g. C₃H₈ (l) + 3½O₂ (g) → 3CO (g) + 4H₂O (l).
Carbon monoxide is colourless and odourless, making it hard to detect without a sensor.
CO binds irreversibly to haemoglobin, preventing oxygen transport; this causes dizziness, loss of consciousness and potentially death.
With very limited oxygen, carbon is produced as soot; a yellow, sooty flame signals incomplete combustion, and compounds with higher carbon percentage produce more soot.

Fossil Fuels and Carbon Dioxide Production

Fossil fuels include coal, oil and natural gas; they are hydrocarbons formed from buried dead plants and animals millions of years ago.
They are non-renewable (finite) and cannot be replaced quickly once used.
Advantages: coal is cheap and widely available; oil has high energy density and is easily processed by fractional distillation and cracking; natural gas is the cheapest and burns relatively cleanly with a blue flame.
Disadvantages: all are finite; combustion releases CO₂ (global warming), SO₂ (acid rain), particulates (global dimming) and CO; mining and drilling cause habitat destruction and safety risks.
Specific energy is a measure of the energy stored in a substance; different fuels release different amounts of energy when combusted.
As the hydrocarbon chain length increases, carbon content increases, so more CO₂ and CO/C are produced, London dispersion forces are stronger (less volatile), and less energy is released per unit mass.
Longer hydrocarbons are also more likely to undergo incomplete combustion.
Methane releases the most energy per unit mass of fuel among the straight-chain alkanes.

Carbon Dioxide Levels and the Greenhouse Effect

Atmospheric CO₂ is rising due to human activities: combustion of fossil fuels (electricity generation, transport, construction), deforestation and livestock farming.
The main driver is the combustion of fossil fuels, which releases carbon stored for millions of years.
Stations such as the Mauna Loa Observatory take quantitative measurements; CO₂ records date from 1958 and methane from 1984.
CO₂ levels constantly change due to seasonal fluctuations in photosynthesis, which removes CO₂ from the atmosphere.
Main greenhouse gases: carbon dioxide (CO₂), methane (CH₄), nitrous oxides (NOₓ) and water vapour (H₂O).
The sun emits shortwave radiation; Earth absorbs it and re-emits longwave infrared radiation, which greenhouse gases absorb and re-radiate in all directions, trapping heat.
This natural warming is the greenhouse effect; without it Earth's temperature would swing wildly, like on Mars.
Human activities increase greenhouse gas levels, trapping more heat and causing the enhanced greenhouse effect and global warming.

The greenhouse effect

Biofuels

Renewable resources will not run out in the foreseeable future and can be replaced over a short period; non-renewable resources are finite and cannot be replaced quickly.
The three main biofuels are bioethanol, biodiesel and biogas, all made from organic compounds produced by biological carbon fixation.
Bioethanol: plants absorb CO₂ by photosynthesis (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂), then glucose is converted to ethanol by fermentation; it can be carbon neutral because CO₂ absorbed equals CO₂ released on burning.
Biodiesel is made from renewable vegetable oils by transesterification with methanol, catalysed by acid or alkali (alkaline catalysts like NaOH or KOH are more common); excess methanol shifts the reversible equilibrium towards products, giving up to 98% yield.
Biogas is made when organic matter is broken down by microorganisms in the absence of oxygen (anaerobic conditions); it is mostly methane and carbon dioxide.
Carbohydrates such as glucose produce biogas with 50.0% methane: C₆H₁₂O₆ (s) → 3CO₂ (g) + 3CH₄ (g).
Advantages of biofuels: carbon neutral, renewable and sustainable if crops are replanted; reduce greenhouse gas emissions and landfill waste; can generate income and jobs.
Disadvantages: high conversion and harvesting costs, land-use conflict with food crops, deforestation, soil nutrient depletion, fertiliser and pesticide use, and generally lower specific energy than fossil fuels.

Fuel Cells

A fuel cell is an electrochemical cell in which a fuel donates electrons at one electrode and oxygen gains electrons at the other.
As fuel enters the cell it is oxidised, setting up a potential difference (voltage); different electrolytes and fuels give different types of fuel cell.
The hydrogen-oxygen fuel cell has separate inlets for hydrogen and oxygen, an outlet for water, an electrolyte of aqueous sodium hydroxide, and a semi-permeable membrane separating the gases.
Half-equations (alkaline): 2H₂ (g) + 4OH⁻ (aq) → 4H₂O (l) + 4e⁻ (Eθ = –0.83 V) and O₂ (g) + 2H₂O + 4e⁻ → 4OH⁻ (aq) (Eθ = +0.40 V).
Overall: 2H₂ (g) + O₂ (g) → 2H₂O (l) with Eθ = +1.23 V.
Advantages of hydrogen fuel cells: only product is water (environmentally friendly), reaction occurs at room temperature avoiding combustion, no NOₓ produced, and the water can supplement drinking water for astronauts.
Disadvantages: hydrogen is highly flammable, needs heavy thick-walled storage tanks, is mostly sourced from fossil fuels, and has low energy density by volume.
Fuel cells operate continuously as long as fuel and oxidant are supplied; the energy is not stored in the cell, so they do not need recharging.

A hydrogen–oxygen fuel cell

Methanol Fuel Cells

The methanol fuel cell works like the hydrogen fuel cell, but the fuel (source of H⁺ ions) is methanol rather than hydrogen.
It consists of separate inlets for methanol and oxygen, outlets for carbon dioxide and water, and an electrolyte typically a proton exchange membrane.
Half-equations: CH₃OH (aq) + H₂O (l) → CO₂ (g) + 6H⁺ (aq) + 6e⁻ and O₂ (g) + 4H⁺ (aq) + 4e⁻ → 2H₂O (l).
Overall equation: CH₃OH (aq) + 1.5O₂ (g) → CO₂ (g) + 2H₂O (l).
Advantages over hydrogen fuel cells: easier to store and transport, operates at low pressure and temperature, longer membrane lifespan, higher energy density per unit volume, can be made from renewable resources, and lower greenhouse gas emissions than hydrogen from fossil fuels.
Disadvantages: methanol is toxic and highly flammable, commonly made from non-renewable fossil fuels, lower voltage and power output per unit mass, low efficiency due to methanol crossing the membrane, requires expensive catalysts (e.g. ruthenium, palladium), and produces CO₂.

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பதிவு செய்க — இலவசம்உள்நுழைக

பயிற்சி கேள்விகள்

இலவச முன்னோட்டம் — 64-இல் 8 கேள்விகள். அனைத்தையும் பார்க்க பதிவு செய்யவும்.

1.Which of the following is a definition of complete combustion?
Easy
- ABurning in a plentiful supply of oxygen to produce carbon dioxide and water
- BBurning in a limited supply of oxygen to produce carbon monoxide and water
- CBurning in a limited supply of oxygen to produce carbon and water
- DBurning in a plentiful supply of oxygen to produce carbon monoxide and hydrogen
2.Which of the following is the main greenhouse gas discussed in the context of global warming?
Easy
- ACarbon dioxide
- BOxygen
- CNitrogen
- DArgon
3.Incomplete combustion of a hydrocarbon fuel produces carbon monoxide and/or carbon, as well as water.
Easy
True or false?
4.Which observation indicates that incomplete combustion is occurring in a Bunsen burner?
Easy
- AA blue, non-luminous flame
- BA yellow, luminous flame
- CA lilac flame
- DA bright white flame
5.Which of the following are greenhouse gases? (select all that apply)
Medium
- ACarbon dioxide
- BMethane
- COxygen
- DWater vapour
- ENitrogen
6.Match each type of combustion with its characteristic product or observation.
Easy
- Complete combustion
- Incomplete combustion (limited oxygen)
- Incomplete combustion (very limited oxygen)
- Combustion of magnesium
- Combustion of sulfur
- Carbon dioxide and water
- Carbon monoxide and water
- Carbon and water
- Bright white flame, forms magnesium oxide
- Blue flame, forms sulfur dioxide
7.Place the steps of the greenhouse effect in the correct order, starting from the Sun's radiation.
Medium
- Sun emits shortwave radiation that reaches Earth's surface
- Earth absorbs energy and re-emits it as longwave infrared radiation
- Greenhouse gases absorb some of the infrared radiation
- Greenhouse gases re-radiate energy in all directions, trapping heat
8.Which of the following is a biofuel?
Medium
- ABioethanol
- BPetrol
- CDiesel from crude oil
- DNatural gas

மேலும் கேள்விகள்

9.Which of the following is a disadvantage of using hydrogen fuel cells?
Medium
- AHydrogen is highly flammable and requires heavy storage tanks
- BThey produce harmful nitrogen oxides
- CThey need to be recharged regularly
- DThey emit carbon dioxide as the only product
10.Biofuels are considered renewable resources because they can be replaced over a relatively short period of time.
Easy
True or false?
11.Which of the following are necessary for combustion to occur? (select all that apply)
Medium
- AFuel
- BOxygen
- CAn ignition source
- DWater
- ECarbon dioxide
12.Match each fuel with its specific energy value.
Medium
- Hydrogen
- Methane
- Octane
- Ethanol
- 142 MJ/kg
- 55.6 MJ/kg
- 47.9 MJ/kg
- 29.7 MJ/kg
13.Which of the following statements about the greenhouse effect are correct? (select all that apply)
Medium
- AThe sun emits shortwave radiation that reaches Earth's surface.
- BGreenhouse gases absorb infrared radiation emitted by Earth.
- CThe greenhouse effect is entirely caused by human activities.
- DWithout the greenhouse effect, Earth's temperature would be much colder.
- EGreenhouse gases re-radiate energy in all directions.
14.Place the steps of bioethanol production in the correct order.
Medium
- Photosynthesis produces glucose
- Fermentation converts glucose to ethanol
- Combustion of ethanol releases energy
15.Which of the following are advantages of hydrogen fuel cells? (select all that apply)
Medium
- AWater is the only product.
- BThey produce no nitrogen oxides.
- CThey can be used in spacecraft.
- DHydrogen storage is lightweight.
- EThey are completely renewable.
16.The complete combustion of a hydrocarbon produces carbon dioxide and water.
Easy
True or false?
17.Arrange the following fuels in order of increasing specific energy (lowest first).
Hard
- Ethanol (29.7 MJ/kg)
- Octane (47.9 MJ/kg)
- Methane (55.6 MJ/kg)
- Hydrogen (142 MJ/kg)
18.Which of the following are products of the incomplete combustion of a hydrocarbon? (select all that apply)
Medium
- ACarbon monoxide
- BCarbon (soot)
- CWater
- DCarbon dioxide
- EHydrogen gas
19.Match each greenhouse gas with its main source.
Medium
- Carbon dioxide
- Methane
- Nitrous oxides
- Water vapour
- Combustion of fossil fuels
- Livestock and landfills
- Impurities in fossil fuels
- Evaporation and combustion
20.Which of the following are disadvantages of biofuels? (select all that apply)
Medium
- AHigh production costs
- BLand use conflict with food crops
- CLower specific energy than fossil fuels
- DThey are non-renewable
- EThey produce no greenhouse gases when burned
21.A student burns a sample of a hydrocarbon fuel in a limited supply of oxygen. Which observation would most strongly suggest that carbon (soot) is being formed?
Medium
- AA blue, non-luminous flame
- BA yellow, sooty flame
- CA colourless gas with no smell
- DWater condensing on the glass
22.A fuel cell converts chemical energy into electrical energy. In a hydrogen-oxygen fuel cell with an alkaline electrolyte, which half-equation occurs at the negative electrode?
Medium
- A2H₂(g) + 4OH⁻(aq) → 4H₂O(l) + 4e⁻
- BO₂(g) + 2H₂O + 4e⁻ → 4OH⁻(aq)
- C2H₂(g) + O₂(g) → 2H₂O(l)
- DO₂(g) + 4H⁺(aq) + 4e⁻ → 2H₂O(l)
23.In a methanol fuel cell, methanol is oxidised at the negative electrode. Which equation correctly represents this half-reaction?
Medium
- ACH₃OH(aq) + H₂O(l) → CO₂(g) + 6H⁺(aq) + 6e⁻
- BCH₃OH(aq) + 6H⁺(aq) + 6e⁻ → CO₂(g) + H₂O(l)
- CCH₃OH(aq) + 1.5O₂(g) → CO₂(g) + 2H₂O(l)
- DO₂(g) + 4H⁺(aq) + 4e⁻ → 2H₂O(l)
24.Which of the following is the main reason why the graph of atmospheric carbon dioxide concentration at Mauna Loa is not smooth but shows a zigzag pattern?
Medium
- ASeasonal changes in the rate of photosynthesis
- BVolcanic eruptions releasing carbon dioxide
- CVariations in the Earth's distance from the Sun
- DRandom errors in the measuring instruments
25.A diesel fuel contains tetradecane, C₁₄H₃₀. It burns with a sooty yellow flame. Which balanced equation, including state symbols, represents this incomplete combustion forming carbon?
Medium
- AC₁₄H₃₀(l) + 14.5O₂(g) → 14C(s) + 15H₂O(l)
- BC₁₄H₃₀(l) + 21.5O₂(g) → 14CO₂(g) + 15H₂O(l)
- CC₁₄H₃₀(l) + 14O₂(g) → 14CO(g) + 15H₂O(l)
- DC₁₄H₃₀(l) + 7O₂(g) → 14C(s) + 15H₂O(l)
26.A 5.0 cm³ sample of biodiesel (density = 0.780 g cm⁻³) is burned in a calorimeter containing 1 dm³ of water. The water temperature rises from 20.0 °C to 55.0 °C. Given that the specific heat capacity of water is 4.18 J g⁻¹ K⁻¹, what is the heat absorbed by the water, in kJ?
Medium
- A146 kJ
- B14.6 kJ
- C1460 kJ
- D0.146 kJ
27.Using the data from the previous question, what is the enthalpy change of combustion of the biodiesel sample, in kJ g⁻¹?
Hard
- A37.4 kJ g⁻¹
- B3.74 kJ g⁻¹
- C374 kJ g⁻¹
- D0.374 kJ g⁻¹
28.In a hydrogen-oxygen fuel cell, the electrodes are often made of a porous mixture of carbon-supported platinum. Why must the electrodes be porous?
Medium
- ATo increase the surface area for the reaction between hydrogen, oxygen and the electrolyte
- BTo allow the water product to drain away easily
- CTo prevent the hydrogen and oxygen gases from mixing
- DTo reduce the cost of the expensive platinum catalyst
29.Which statement best explains why a hydrogen fuel cell does not need to be recharged?
Medium
- AIt operates continuously as long as hydrogen and oxygen are supplied
- BIt stores electrical energy in its electrodes
- CIt converts water back into hydrogen and oxygen when reversed
- DIt uses a rechargeable battery as a backup
30.A student compares the energy density of methanol and hydrogen. Which statement correctly describes the advantage of methanol fuel cells over hydrogen fuel cells?
Medium
- AMethanol has a higher energy density by volume, making storage and transport easier
- BMethanol has a higher energy density by mass, so it produces more energy per gram
- CMethanol fuel cells produce no carbon dioxide, unlike hydrogen fuel cells
- DMethanol fuel cells operate at higher temperatures, increasing efficiency
31.Which of the following statements about the combustion of metals and non-metals are correct? (select all that apply)
Medium
- AMagnesium burns in air with a bright white flame to form a basic oxide
- BSulfur burns in oxygen with a blue flame to form an acidic oxide
- CCopper combusts in air with a bright flame to form copper oxide
- DThe combustion of metals always produces acidic oxides
- ENon-metal oxides typically dissolve in water to give pH < 7
32.Which of the following factors contribute to the enhanced greenhouse effect? (select all that apply)
Hard
- ABurning fossil fuels for electricity generation
- BDeforestation for agriculture
- CIncreased livestock farming releasing methane
- DVolcanic eruptions releasing sulfur dioxide
- EUse of biofuels made from crops
33.Incomplete combustion of a hydrocarbon can produce carbon monoxide, which is colourless and odourless.
Easy
True or false?
34.The complete combustion of a hydrocarbon produces carbon dioxide and water, and is an exothermic reaction.
Medium
True or false?
35.As the chain length of a hydrocarbon increases, it releases more energy per gram and produces less carbon dioxide per gram.
Medium
True or false?
36.Match each fuel cell component with its function.
Medium
- Electrolyte
- Porous electrodes
- Semi-permeable membrane
- Catalyst (platinum)
- Allows ion movement between electrodes
- Provides large surface area for reaction
- Separates the hydrogen and oxygen gases
- Speeds up the electrode reactions
37.A student heats a sample of copper turnings in a Bunsen flame. The copper glows red and a black solid forms, but no flame is seen coming from the metal itself. Which statement best explains this observation?
Medium
- ACopper is too unreactive to combust, but it is oxidised to black copper(II) oxide
- BCopper combusts with a non-luminous flame that cannot be seen in daylight
- CCopper does not react with oxygen at all, so the black solid must be soot
- DCopper only combusts when finely divided as a powder or filings
38.A student burns a sample of biodiesel in a spirit burner under a calorimeter containing 200 g of water. The temperature of the water rises by 30.0 °C. The mass of fuel burned is 0.500 g. Use c = 4.18 J g⁻¹ K⁻¹. What is the enthalpy change of combustion of the biodiesel in kJ g⁻¹?
Hard
- A50.2 kJ g⁻¹
- B25.1 kJ g⁻¹
- C0.502 kJ g⁻¹
- D251 kJ g⁻¹
39.In a hydrogen-oxygen fuel cell, the electrodes must be porous so that the hydrogen and oxygen gases can come into contact with the electrolyte and the catalyst over a large surface area.
Easy
True or false?
40.A student compares the energy released per gram when burning equal masses of methane (CH₄), octane (C₈H₁₈) and decane (C₁₀H₂₂). Which statement correctly describes the trend?
Medium
- AMethane releases the most energy per gram; energy per gram decreases as chain length increases
- BDecane releases the most energy per gram; energy per gram increases as chain length increases
- CAll three release the same energy per gram because they are all hydrocarbons
- DOctane releases the most energy per gram because it is the middle member of the series
41.Calculate the mass of carbon dioxide produced, in grams, when 1.00 g of butane (C4H10) undergoes complete combustion. Use Mr(C4H10) = 58.12 g mol-1 and Mr(CO2) = 44.01 g mol-1. Give your answer to 3 significant figures.
Medium
42.Name the process by which vegetable oils are converted into biodiesel.
Easy
43.Complete the sentence about fuel cells.
Easy
A fuel cell is an electrochemical cell in which a fuel donates ____ at one electrode and oxygen gains ____ at the other electrode.
44.Calculate the volume of one mole of methanol at room temperature and pressure, given its density is 0.792 g cm⁻³ and its molar mass is 32.04 g mol⁻¹. Give your answer in cm³ to 3 significant figures.
Medium
45.Calculate the mass of carbon dioxide produced, in grams, when 1.00 g of butane (C₄H₁₀) undergoes complete combustion. Use Mr(C₄H₁₀) = 58.12 g mol⁻¹ and Mr(CO₂) = 44.01 g mol⁻¹. Give your answer to 3 significant figures.
Medium
46.A 5.0 cm³ sample of biodiesel (density = 0.780 g cm⁻³) is burned in a calorimeter containing 1 dm³ of water. The water temperature rises from 20.0 °C to 55.0 °C. Calculate the enthalpy change of combustion of the biodiesel, in kJ g⁻¹. Use c = 4.18 J g⁻¹ K⁻¹. Give your answer to 3 significant figures.
Hard
47.Complete the sentence about the greenhouse effect.
Medium
Greenhouse gases absorb ____ radiation emitted by the Earth's surface and re-radiate it in all directions.
48.Complete the sentence about biodiesel production.
Medium
Vegetable oils are reacted with methanol in a process called ____ to produce biodiesel.
49.Name the type of radiation that all greenhouse gases absorb.
Medium
50.Calculate the mass of carbon dioxide produced, in grams, when 2.00 g of butane (C₄H₁₀) undergoes complete combustion. Use Mr(C₄H₁₀) = 58.12 g mol⁻¹ and Mr(CO₂) = 44.01 g mol⁻¹. Give your answer to 3 significant figures.
Medium
51.Calculate the volume, in cm³, of one mole of methanol at room temperature and pressure. The density of methanol is 0.792 g cm⁻³ and its molar mass is 32.04 g mol⁻¹. Give your answer to 3 significant figures.
Medium
52.A 5.0 cm³ sample of biodiesel (density = 0.780 g cm⁻³) is burned in a calorimeter containing 1 dm³ of water. The water temperature rises from 20.0 °C to 55.0 °C. Calculate the heat absorbed by the water, in kJ. Use the specific heat capacity of water = 4.18 J g⁻¹ °C⁻¹ and assume the density of water is 1.00 g cm⁻³.
Medium
53.Explain why carbon monoxide is dangerous if inhaled.
Hard
54.Explain why fossil fuels contribute more to climate change than biofuels.
Hard
55.Explain how an electric current is generated in a hydrogen-oxygen fuel cell.
Hard
56.Explain the molecular mechanism of the greenhouse effect, in relation to carbon dioxide.
Hard
57.10 cm³ of a gaseous hydrocarbon CₓHᵧ was reacted with 100 cm³ of excess oxygen in a closed container. After cooling, the final volume was 95 cm³. This mixture was passed through concentrated aqueous sodium hydroxide, which reduced the volume to 75 cm³. Deduce the reacting volume ratio of hydrocarbon, oxygen, and carbon dioxide, and hence determine the molecular formula of the hydrocarbon.
Challenge
58.Calculate the mass of carbon dioxide produced, in grams, when 1.00 g of butane (C4H10) undergoes complete combustion. Use Mr(C4H10) = 58.12 g mol-1 and Mr(CO2) = 44.01 g mol-1. Give your answer to 3 significant figures.
Medium
- A3.03 g
- B5.03 g
- C2.03 g
- D4.03 g
59.Calculate the volume of one mole of methanol at room temperature and pressure, given its density is 0.792 g cm⁻³ and its molar mass is 32.04 g mol⁻¹. Give your answer in cm³ to 3 significant figures.
Medium
- A36.5 cm³
- B40.5 cm³
- C44.5 cm³
- D48.5 cm³
60.Calculate the mass of carbon dioxide produced, in grams, when 1.00 g of butane (C₄H₁₀) undergoes complete combustion. Use Mr(C₄H₁₀) = 58.12 g mol⁻¹ and Mr(CO₂) = 44.01 g mol⁻¹. Give your answer to 3 significant figures.
Medium
- A3.03 g
- B2.03 g
- C4.03 g
- D5.03 g
61.A 5.0 cm³ sample of biodiesel (density = 0.780 g cm⁻³) is burned in a calorimeter containing 1 dm³ of water. The water temperature rises from 20.0 °C to 55.0 °C. Calculate the enthalpy change of combustion of the biodiesel, in kJ g⁻¹. Use c = 4.18 J g⁻¹ K⁻¹. Give your answer to 3 significant figures.
Hard
- A44.8 kJ g⁻¹
- B37.4 kJ g⁻¹
- C33.7 kJ g⁻¹
- D41.1 kJ g⁻¹
62.Calculate the mass of carbon dioxide produced, in grams, when 2.00 g of butane (C₄H₁₀) undergoes complete combustion. Use Mr(C₄H₁₀) = 58.12 g mol⁻¹ and Mr(CO₂) = 44.01 g mol⁻¹. Give your answer to 3 significant figures.
Medium
- A5.06 g
- B7.06 g
- C8.06 g
- D6.06 g
63.Calculate the volume, in cm³, of one mole of methanol at room temperature and pressure. The density of methanol is 0.792 g cm⁻³ and its molar mass is 32.04 g mol⁻¹. Give your answer to 3 significant figures.
Medium
- A44.5 cm³
- B36.5 cm³
- C48.5 cm³
- D40.5 cm³
64.A 5.0 cm³ sample of biodiesel (density = 0.780 g cm⁻³) is burned in a calorimeter containing 1 dm³ of water. The water temperature rises from 20.0 °C to 55.0 °C. Calculate the heat absorbed by the water, in kJ. Use the specific heat capacity of water = 4.18 J g⁻¹ °C⁻¹ and assume the density of water is 1.00 g cm⁻³.
Medium
- A146.3 kJ
- B160.9 kJ
- C131.7 kJ
- D175.5 kJ

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இந்த தலைப்பிற்கான ஒவ்வொரு கேள்வியையும், ஸ்லைடுகளையும், ஃப்ளாஷ் கார்டுகளையும் மற்றும் திருப்புதல் குறிப்புகளையும் பார்க்க இலவச கணக்கை உருவாக்கவும்.

பதிவு செய்க — இலவசம்உள்நுழைக

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இந்த தலைப்பிற்கான முந்தைய தேர்வு பயிற்சி விரைவில் வருகிறது.

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