One use of urea is as a fertilizer.

Structural formula of propanone

OR

Wöhler first prepared the organic compound urea from the inorganic compound ammonium cyanate in the laboratory.

An example of a biodegradable natural polymer is starch.

The troposphere is the layer of the atmosphere where the pressure is the highest. This is because the troposphere contains the majority of the atmosphere's mass, including water vapor, gases, and particulate matter.

Molar Mass of O₂ = 32

Molar Mass of CO₂ = 44

Moles of O₂ = 32\over 32 = 1

Moles of CO₂ = 44\over 44 = 1

Ideal gases Equation: PV = nRT

or, V ∝ nRT\over P

At constant temperature and pressure, the volume is directly proportional to the number of moles of gas:

V_1\over V_2 =n_1\over n_2

or, V_1\over V_2 =1\over 1

Since both gases have the same number of moles under the same conditions of temperature and pressure, the ratio of their volumes is 1:1.

OR

V_1​ = 520 cm³

V₂​ = 700 cm³

T₁​= −13ºC = 273 - 13 = 260 K

Charles' Law: V_1\over T_1 = V_2\over T_2

T₂ = V_2\over T_2 × 260 = 350 K

or, T₂ = 350 K - 273 = 77°C

The final temperature is 77°C.

Two Features of the Image Formed by a Simple Camera:

1. Inverted: The image produced by a simple camera is inverted (upside down) relative to the object.
2. Real: The image formed is a real image, meaning it can be projected onto a screen.

OR

The image of an extended object placed at infinity will be formed at the focal point of the concave mirror.

Feature of the Image: The image will be point-sized (highly diminished) and inverted.

Similarity:

Both emf and potential difference measure electrical energy per unit charge.

Dissimilarity:

Emf is the voltage generated by a source with no current, while the potential difference is the voltage between two points when current flows.

An example of an ionic compound that does not obey the octet rule is lithium oxide (Li₂O).

Lithium (Li) has 3 electrons and loses 1 electron to form Li⁺, achieving a stable configuration with only 2 electrons, not 8 (octet).

Oxygen (O) gains 2 electrons to form O^2-, which follows the octet rule.

OR

Sodium chloride (NaCl) has a much higher melting point than glucose because NaCl has strong ionic bonds that require more energy to break. Whereas, glucose has weaker covalent bonds and intermolecular forces, leading to a lower melting point.

Ionic Bond Between Na and F:

• Sodium (Na) (atomic number 11) has 1 electron in its outer shell and tends to lose this electron to achieve a stable electron configuration, forming Na⁺.
• Fluorine (F) (atomic number 9) has 7 electrons in its outer shell and needs 1 more electron to complete its octet, forming F^-.

When Na and F react:  Na+F→Na ⁺ +F ^- (Ionic Bond)

Covalent Bond Between H and F:

• Hydrogen (H) (atomic number 1) has 1 electron and can share it to achieve a stable configuration.
• When H and F combine, they share electrons to complete their outer shells:

When H and F react:  H + F → HF (Covalent Bond)

When nitrogen gas is passed over heated calcium carbide (CaC₂) at 1100°C, calcium cyanamide (CaCN₂) and carbon (C) are formed.

Balanced Chemical Equation:

CaC₂ ​+ N₂ {\overset \text {1100\ °C}{\longrightarrow}} CaCN2​ + C

This reaction is used in the production of calcium cyanamide, which is an important fertilizer.

Balanced Chemical Equation for the Thermit Process:

Fe_2​O₃ ​+ 2Al → 2Fe + Al₂​O₃

​In this reaction, ferric oxide (Fe_2​O₃) reacts with aluminium (Al) to produce metallic iron (Fe) and aluminium oxide (Al₂​O₃).

The thermit process is commonly used for welding railway tracks and repairing metal structures due to the high temperature produced during the reaction.

OR

Balanced Chemical Equation:

Fe + CuSO_4​ → FeSO₄ ​+ Cu

Information from the Reaction:

This reaction shows that iron (Fe) is more reactive than copper (Cu) because iron displaces copper from its compound. Hence, Fe is placed above Cu in the activity series of metals.

Members of a Homologous Series (Alcohols):

The alcohols from the given compounds are:

• CH₃OH (Methanol)
• CH₃CH₂OH (Ethanol)
• CH₃CH₂CH₂OH (Propanol)

OR

A functional group is a specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule. Functional groups determine the properties and reactivity of organic compounds.

Example:

In ethanol (C₂H₅OH), the functional group is the hydroxyl group (-OH).