Chemistry NCFE Released Questions

Front

What are London dispersion forces?

Back

London dispersion forces are weak intermolecular forces that arise from temporary shifts in electron density in atoms or molecules, leading to temporary dipoles.

Front

What is the electron configuration of a neutral atom with 6 valence electrons?

Back

The electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁴.

Front

How do you calculate the molarity of a solution?

Back

Molarity (M) = moles of solute / liters of solution.

Front

What is the principle of equilibrium in a chemical reaction?

Back

At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction.

Front

How many particles are in one mole of a substance?

Back

One mole of a substance contains approximately 6.022 × 10²³ particles (Avogadro's number).

Front

What is the definition of valence electrons?

Back

Valence electrons are the electrons in the outermost shell of an atom that are involved in forming bonds.

Front

What is the significance of STP in chemistry?

Back

STP stands for Standard Temperature and Pressure, which is defined as 0 degrees Celsius (273.15 K) and 1 atmosphere pressure.

Front

What is the difference between covalent bonding and ionic bonding?

Back

Covalent bonding involves the sharing of electron pairs between atoms, while ionic bonding involves the transfer of electrons from one atom to another, resulting in charged ions.

Front

What is the formula for calculating the number of moles from mass?

Back

Number of moles = mass (g) / molar mass (g/mol).

Front

What happens during the process of vaporization?

Back

Vaporization is the process where liquid molecules gain enough energy to enter the gas phase.