MYP 4 Chemistry: Stoichiometry Flashcards

These flashcards cover key vocabulary from the MYP 4 Chemistry Stoichiometry unit, including concepts like the mole, relative masses, formulas, concentration, and limiting reagents.

Stoichiometry

The branch of chemistry that deals with the quantitative relationships between the amounts of reactants and products in a chemical reaction.

Stoicheion

The Greek word meaning "element."

Metron

The Greek word meaning "measure."

Mole

The fundamental SI unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles.

mol

The symbol used to represent the fundamental SI unit known as the mole.

Avogadro’s constant

The value designated as $6.022 \times 10^{23}$, representing the number of atoms, molecules, or ions in one mole of a substance.

Carbon-12

The isotope used as the standard for defining the mole, previously defined as the number of atoms in exactly $12\,g$ of this substance.

Mass number

The total number of protons and neutrons in the nucleus of an atom.

Isotopes

Atoms of the same element that have the same number of protons and electrons but different numbers of neutrons.

Isotopic natural abundance

The percentage or proportion of atoms of each isotope of an element as it naturally occurs on Earth.

Relative atomic mass ($A_r$)

The average mass of the atoms of an element compared with the mass of a carbon-12 atom.

Relative molecular mass ($M_r$)

The sum of the relative atomic masses ($A_r$) of all the atoms in a chemical formula.

Relative formula mass

A term often used interchangeably with relative molecular mass ($M_r$) to describe the sum of atomic masses in a chemical formula.

Percentage composition

The percent by mass of each element in a compound.

Molar mass

The mass of one mole of a substance, expressed in grams per mole ($g/mol$).

$$g/mol$$

The unit of measurement used for molar mass.

Quantitative analysis

Analysis focused on determining the relative masses of elements to find the exact composition of a compound.

Qualitative analysis

Analysis focused on determining which specific elements are present in a substance.

Empirical Formula

The simplest whole-number ratio of atoms or amount of each element present in a compound.

Molecular Formula

The formula showing the actual number of atoms or amount of elements in one structural unit or one mole of a compound.

Simplest formula

Another name for the empirical formula because it only shows the basic proportional relationship between elements.

Concentration

The distribution of particles in a solution, comparing the amount of solute with the volume of solution.

Solute

The substance that is dissolved in a solution.

$$mol/dm^3$$

A unit of concentration expressed as moles of solute per decimetre cubed of solution.

Decimetre cubed ($dm^3$)

The standard unit of volume used in concentration calculations, equivalent to $1000\,cm^3$.

Titration

A laboratory technique used to determine the concentration of an unknown solution by reacting it with a solution of known concentration.

Limiting reagent

The reactant in a chemical reaction that is completely consumed first, thereby limiting the amount of product that can be formed.

Excess reactant

The reactant that remains in a reaction vessel after the limiting reagent has been completely consumed.

Theoretical mass

The amount of product or reactant calculated to take part in a reaction based on the balanced chemical equation.

Actual mass

The real-world measurement of a substance used or produced in a laboratory experiment.

Thermal decomposition

The breakdown of a substance into simpler substances using heat, such as copper(II) carbonate breaking down into copper oxide and carbon dioxide.

Molar volume at rtp

The volume occupied by one mole of a gas at room temperature and pressure.

Percentage yield

A calculation used to determine the efficiency of a reaction by comparing the actual amount of product obtained to the theoretical amount.

Percentage purity

A measure of the proportion of a desired substance in a sample compared to the total mass of the sample.

Integer multiple ($n$)

The factor calculated as molar mass divided by empirical formula mass, used to convert an empirical formula to a molecular formula.

Microscopic world

The level of chemistry dealing with individual atoms and molecules.

Macroscopic world

The level of chemistry dealing with measurable quantities like grams and liters.

Balanced equation

A chemical equation where the number of atoms of each element is equal on both the reactant and product sides.

Mole card sorting

A task involving matching equivalent statements, such as $1\,mole$ of sodium atoms representing $6.02 \times 10^{23}$ atoms.

Stoicheion and Metron

The two Greek roots of the word stoichiometry.

Burette

A graduated glass tube with a tap at one end, used in titrations to deliver known volumes of a liquid.

Volumetric pipette

A tool used in titration to measure a very precise volume of a liquid solution.

Conical flask

A flask used in titrations to hold the solution being analyzed, allowing for easy swirling.

Indicator

A substance added during titration to signal the end point of a chemical reaction, often by a change in color.

Precise particle counts

A requirement for industries like pharmaceuticals and fertilizers to ensure safety and effectiveness.

Residue

The solid material remaining after a process such as heating or filtration.

Precipitate

The insoluble solid formed in a solution during a chemical reaction, such as in the reaction between $MgSO_4$ and $Na_2CO_3$.

Relative formula unit

A term used when referring to the relative molecular mass ($M_r$) of ionic compounds like sodium chloride ($NaCl$).

Formula mass sum

The method of calculating $M_r$ by adding the atomic masses of all atoms present in a formula.

Stoichiometric relationships

The fixed ratios between reactants and products used to calculate required masses for a reaction.