Explanation

• Spectroscopy is the study of the interaction of light with matter, including the absorption and emission of light.
• It is used to identify elements and compounds by analyzing their characteristic spectra.

Additional information:

• Atomic spectroscopy is used to study the electronic structure of atoms.

Last verified on 29-10-2026

Explanation

• The n+l rule, also called the Madelung rule.
• It is used to determine the order in which atomic orbitals are filled according to their energy.
• Here, n is the principal quantum number and l is the azimuthal (angular momentum) quantum number.
• The orbital with the lower n+l value fills first.
• If two orbitals have the same n+l value, the orbital with the lower n value fills first.

Last verified on 29-10-2026

Explanation

For 2 moles of CO₂:

Molar mass CO₂ = 44 g/mol

1. 88g of CO₂ = 2 mol x 44 g/mol = 88g -> CORRECT
2. 22.414 dm³ = 1 mol at STP, not 2 mol
3. 44g of CO₂ = 1 mol, not 2 mol
4. 6.022 x 10²³ = 1 mol, not 2 mol

Answer: 88g of CO₂

Last verified on 29-10-2026

Explanation

At STP:

22.414 dm³ of any gas = 1 mole

For O₂, 1 mole = 32g

So:

22.414 dm³ O₂ = 32g

1 dm³ O₂ = 32 / 22.414

15 dm³ O₂ = (32 / 22.414) x 15

= 21.41 g

Last verified on 29-10-2026

Explanation

• Actual yield is the amount of product obtained experimentally from a chemical reaction.

Additional information:

• Percent yield is calculated by dividing actual yield by theoretical yield and multiplying by 100.
• Theoretical yield is the maximum amount of product calculated from the balanced chemical equation.

Last verified on 29-10-2026

Explanation

• Viscosity is a measure of a liquid’s resistance to flow due to internal friction between its layers.
• Liquids with high viscosity, such as honey, flow more slowly than liquids with low viscosity, such as water.

Last verified on 29-10-2026

Explanation

• The molar mass of carbon is approximately 12 g/mol, so 12 g of carbon contains 1 mole of atoms.
• The molar mass of magnesium is approximately 24 g/mol, so 24 g of magnesium also contains 1 mole of atoms.
• One mole of any element contains Avogadro's number, 6.022 x 10^23, of atoms.
• Therefore, both samples contain the same number of atoms.

Last verified on 29-10-2026

Explanation

• The value of Planck's constant is 6.63 × 10⁻³⁴ Js.
• This constant is fundamental in quantum mechanics.
• It relating the energy of a photon to its frequency.

Last verified on 29-10-2026

Explanation

• The limiting reactant is the substance that is completely consumed first in a chemical reaction.
• It determines the maximum amount of product that can be formed.
• The excess reactant remains after the limiting reactant has been used up.
• The limiting reactant is identified by comparing the available amounts of reactants with their balanced chemical equation ratios.

Last verified on 29-10-2026

Explanation

• Molecular Orbital Theory (MOT) explains the paramagnetic behavior of oxygen (O₂) because it has two unpaired electrons in its antibonding π* molecular orbitals.
• Unpaired electrons are attracted to an external magnetic field, making oxygen paramagnetic.

Last verified on 29-10-2026