Chapter 1: Matter – Key Concepts & Calculations

30 fill-in-the-blank flashcards covering fundamental particles, isotopes, mole concept, gas volumes, solution concentrations, limiting reagents, and mass spectrometry.

In a neutral atom, the number of protons equals the number of __.

electrons

The __ number of an element is the number of protons in its nucleus.

atomic

The mass number is the total number of and in an atom.

protons; neutrons

Isotopes of an element have the same number of but different numbers of .

protons (and electrons); neutrons

One mole contains __ particles, known as Avogadro’s number.

6.023 × 10²³

At standard temperature and pressure (0 °C, 1 atm), one mole of any gas occupies __ dm³.

22.4

At room temperature (20 °C, 1 atm), one mole of any gas occupies __ dm³.

24.0

The relationship between mass and moles is n = __.

mass (g) / molar mass (g mol⁻¹)

Relative atomic mass (Aᵣ) is defined as the average mass of one atom relative to __ of a C-12 atom.

1/12th

Concentration (mol dm⁻³) = __ / volume (dm³).

moles of solute

The __ reagent is the reactant that is completely consumed in a reaction.

limiting

For dilution, the formula __ = M₂V₂ is used.

M₁V₁

A proton carries a relative charge of __.

+1

A neutron carries a relative charge of __.

0 (zero)

An electron has a relative mass of approximately __ of a proton.

1/1836 (negligible)

In a mass spectrometer, atoms are first ionised to form __ ions.

positive

During deflection in a mass spectrometer, __ ions are deflected more.

lighter (or more highly charged)

The number of peaks in a mass spectrum equals the number of __ present.

isotopes

The height of each peak in a mass spectrum shows the __ of that isotope.

relative abundance

The position (m/e value) of a peak in a mass spectrum indicates the isotope’s __.

relative mass (mass-to-charge ratio)

Stable isotopes of carbon are and .

¹²C; ¹³C

Radioactive isotopes of uranium include and .

²³⁸U; ²³⁵U

The empirical formula gives the simplest whole-number ratio of __ in a compound.

atoms of each element

To determine a molecular formula you need the empirical formula and the compound’s __.

relative molecular mass (Mᵣ)

Molar mass is expressed in the unit __.

g mol⁻¹

The molar volume is the volume occupied by __ of a gas at stated conditions.

one mole

Avogadro’s number is commonly symbolised as __.

NA (NAvogadro)

The symbol for a proton is __.

p⁺ (or ¹₁H⁺)

Electrons are deflected by electric and magnetic fields in the __ direction to protons.

opposite

Neutrons are __ by electric fields.

not deflected