Chemical Reactions and Processes: A Concise Overview
Chemical Equilibrium
The effect of a catalyst on a reaction mixture accelerates the reaction both directly and inversely. Equilibrium is reached more rapidly, but the catalyst does not change the amounts at equilibrium. Kc remains constant.
Factors affecting equilibrium (Le Chatelier’s principle):
- If temperature increases, the equilibrium shifts towards the endothermic reaction.
- If temperature decreases, the equilibrium shifts towards the exothermic reaction.
Acids and Bases
- Arrhenius theory does not
Properties and Types of Metals and Alloys
Metals and Alloys
Metals and alloys are mineral materials composed of one or more metallic elements and may contain non-metallic elements in small proportions. If a material consists of a single chemical element, it is a pure metallic material. When it consists of more than one chemical element, it is an alloy.
Pure Metals
Pure metals are rarely obtained directly from nature. Isolating them from the minerals they contain requires complex transformation processes.
Properties:
- High hardness.
- Suitable for
Key Chemistry Definitions: Elements, Compounds, and Laws
Key Chemistry Definitions
- Pure Substance: Homogeneous matter that cannot be broken down through simple physicochemical processes.
- Element: A pure substance that cannot be broken down into simpler substances.
- Compound: A substance made of two or more different elements.
- Chemical Formula: Expresses the qualitative and quantitative composition of a given substance. The number in subscript form indicates the number of atoms.
- Ionic Species: A formula that takes a superscript indicating the net electrical
Understanding Nuclear Reactions, Fission, and Radioactivity
Energy Diagrams and Reaction Types
Graph Analysis:
- Product Energy: The product energy is represented by the middle value, approximately 30 kcal.
- Reagent Energy: The reagent energy is below 20 kcal.
- ΔH (Enthalpy Change): ΔH = Product Energy – Reagent Energy = 30 kcal – 20 kcal = 10 kcal. The reaction is exothermic, but the ΔH value is positive, which is unusual and may indicate an error in the data. Exothermic reactions typically have negative ΔH values.
- Activation Energy (Ea): The activation energy
Coordination Compounds: Roles in Biology, Chemistry, and Metallurgy
Coordination Compounds: Applications and Stability
9.27. Discuss briefly, giving an example in each case, the role of coordination compounds in:
(a) Biological systems
(b) Analytical chemistry
(c) Medicinal chemistry
(d) Extraction/metallurgy of metals
Answer:
(i) Coordination compounds are of great importance in biological systems. The pigment responsible for photosynthesis, chlorophyll, is a coordination compound of magnesium. Haemoglobin, the red pigment of blood which acts as an oxygen carrier,
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Understanding Sunset and Sunrise
Why is it assumed that the sun needs to be 6° below the horizon for it to get dark? Even when the sun is below the horizon, its light can still reach us because the Earth’s atmosphere acts like a giant prism, scattering the sun’s rays. This scattering causes the sky to continue to be illuminated even after the sun has set or before it has risen. The atmosphere also refracts the sunlight, bending the light around the curvature of the Earth. So, while the curvature
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