Stoichiometry and Atomic Mass Concepts

Which of the following represents a positive charge ion in ionic compounds?

The empirical formula of a compound represents the exact number of atoms of each element in a molecule.

What is produced when zinc reacts with hydrochloric acid?

The _____ ion has the formula NH4+.

Match the following metals with their ions:

What is the relative atomic mass (Ar) based on?

A sulfate ion has the chemical formula SO4²-.

Relative molecular mass (Mr) is the sum of relative atomic masses of _____ compounds.

What is Avogadro's constant?

1 mole of any gas occupies 22 dm3 at room temperature.

What is the empirical formula of sulfur oxide formed from 32g of sulfur and 32g of oxygen?

The formula to calculate moles is n = mass / __________.

If 2.4g of magnesium reacts with excess dilute hydrochloric acid, what is the volume of hydrogen gas produced?

The percentage yield is the ratio of actual yield to theoretical yield expressed as a percentage.

For magnesium reacting with hydrochloric acid, the ratio of Mg to H2 is __________.

Match the following calculations to their respective outcomes:

Stoichiometry

Stoichiometry is the calculation of reactants and products in a chemical reaction.
Formulae of elements and compounds must be known.
Molecular formula: the number and type of atoms in a molecule.
Empirical formula: simplest whole number ratio of elements in a compound.
Simple compound formula can be derived from models or diagrams.
Word and symbol equations show reactant-product transformations, including state symbols.
Ionic compound formulae are derived from the relative number of ions, and their charges.
Polyatomic ions are groups of atoms that behave as a single unit, for example: carbonate (CO₃²⁻), nitrate (NO₃⁻), ammonium (NH₄⁺), hydroxide (OH⁻), and sulfate (SO₄²⁻).
Examples of metals: Group 1 (K⁺, Na⁺), Group 2 (Ca²⁺, Mg²⁺), Group 3 (Al³⁺), Transition metals (Zn²⁺, Cu⁺, Cu²⁺, Ag⁺, Fe²⁺, Fe³⁺, Cr³⁺).

Relative Masses of Atoms and Molecules

Relative atomic mass (A_r) is the average mass of isotopes compared to ¹/₁₂ of ¹²C.
Relative molecular mass (M_r) of covalent compounds is the sum of relative atomic masses.
Relative formula mass (M_r) of ionic compounds is the sum of relative atomic masses.
Calculating reacting masses involves simple proportions, without moles.

The Mole and Avogadro Constant

The mole (mol) is the unit of amount of substance.
One mole contains 6.02 x 10²³ particles (Avogadro constant).
Amount of substance (mol) = mass (g) / molar mass (g/mol)
Calculations can find molar mass, amount of substance, masses, and the number of particles.
Molar gas volume of a gas under room temperature and pressure is 24 dm³.

Gas Calculations

1 mole of any gas occupies 24 dm³ at room temperature and pressure (r.t.p. = 25°C, 1 atm).
Gas volume calculations involve stoichiometry.

Percentage Yield

Percentage yield is the ratio of the actual mass obtained to the theoretical mass, multiplied by 100%.
Actual yield is the mass of a product obtained in a chemical reaction.
Theoretical yield is the maximum mass of product that could be produced.

This quiz covers the essential concepts of stoichiometry, including the calculation of reactants and products in chemical reactions. You will explore molecular and empirical formulas, the role of ionic compounds, and the fundamentals of relative atomic mass. Test your knowledge and understanding of these core topics in chemistry.