Fuels

​Fuels

​Comnbustion reactions:

​A combustion reaction involves two important reactants: fuel (a combustible substance) oxygen gas.(oxidizer)

! In all cases, the combustible material reacts with oxygen, and produces metallic or non-metallic oxides. These reactions are highly exothermic since the molecules produced are energetically more stable than the reactant fuel and oxygen gas.

​Combustion of metals

​Nearly all metals react with oxygen to form metallic oxides.

​2Mg(s) + O2(g) → 2MgO(s) ΔH is negative

​https://youtu.be/HEU_tblr5Ko

​Less reactive metals also combine with oxygen. For example, iron, copper, and silver react with oxygen to form their own metallic oxides.

​4Ag(s) + O2(g) → 2Ag2O(s) ΔH is negative (praktiski notiek ļoti lēni)

Multiple Choice

Which of the following metals is most reactive in combustion?

A. Gold
B. Magnesium
C. Copper
D. Silver

• A

• B

• C

• D

Multiple Choice

What type of energy is released during the combustion of metals?

• Light and heat

• electrical

• kinetic

• Nuclear energy

Multiple Choice

What is the term used to describe the slow oxidation of metals like iron?
A. Rusting
B. Tarnishing
C. Corrosion
D. All of the above

• A

• B

• C

• D

Multiple Choice

What's the product of the combustion reaction of lithium?

• Lithium carbonate (Li2CO3)
• Lithium oxide (Li2O)
• Lithium chloride (LiCl)
• Lithium hydroxide (LiOH)

​Combustion of non-metals

​onversely, many non-metals react with oxygen to form non-metallic oxides. These oxides do not have fixed ratios, so these combustion reactions can produce several different product oxides for the same non-metal fuel.

Multiple Choice

What is a common environmental issue caused by the combustion of non-metals like sulfur?
A. Global warming
B. Acid rain
C. Ozone layer depletion
D. Soil erosion

• A

• B

• C

• D

Multiple Choice

Which of the following is a product of the combustion of carbon in sufficient oxygen?

• B. CO₂
• C. CH₄
• D. C₂H₆
• A. CO

​Combustion of organic compounds In the complete combustion of methane gas, seen below, both the carbon and hydrogen atoms in the reactant molecules experience a gain in oxygen, and are fully oxidised.



CH4(g) + O2(g) → CO2(g) + H2O(g) ∆H is negative

​All organic compounds, especially those that contain only hydrogen and carbon (hydrocarbons), as well as alcohols, easily undergo complete combustion reactions that produce only carbon dioxide and water.

​Combustion of organic compounds

​CH3CH2OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) ∆H is negative

​https://youtu.be/UfXXQRAvLi0

​Incomplete combustion of organic compounds

Yellow and orange wavelengths of visible light (≅550 nm) have relatively long wavelengths and therefore low energies. Blue light has a shorter wavelength (≅430 nm) and therefore a higher energy. you discovered that the wavelength of light produced in an emission spectrum is inversely related to the energy of the wave

Multiple Choice

2C + O2 --> 2CO is

• incomplete combustion

• complete combustion

Multiple Select

products of incoplete combustion of C_xH_y

• H2O

• C

• CO

• CO2

Multiple Select

incomplete combustion of alcohols can produce:

• CO

• C

• H2O

• CO2

Multiple Choice

Which of the following correctly describes an incomplete combustion reaction involving methanol and a limited supply of oxygen gas?

• A

• B

• C

• D

Multiple Choice

Which equation(s) correctly show the incomplete combustion reactions of methanol?

• I and II

• I

• II and III

• I, II, III