Elements, Atoms, Molecules, Compounds, and Ions

What distinguishes an element from other substances?

What is the fundamental particle of an element that retains the properties of that element?

Which of the following best describes a molecule?

What distinguishes a compound from a molecule?

How does an ion differ from an atom?

Which type of substance is composed of a single atom?

Which of the following represents a diatomic molecule?

What is a key requirement for writing chemical equations at A-level?

What is the purpose of including state symbols in chemical equations?

In ionic equations, what are spectator ions?

Which of the following acids is NOT typically used in laboratory experiments at A-level?

What gas is produced when an acid reacts with a metal, and how is it tested?

What products are formed when an acid reacts with a metal oxide or hydroxide?

What happens when an acid reacts with a metal carbonate?

What evidence suggests carbon dioxide is evolved from a reaction?

What type of reaction involves one element replacing another in a compound?

What is required to initiate displacement reactions in solid state, like the thermite reaction?

In the thermite reaction, what element displaces iron in iron oxide?

Which of the following statements accurately describes the reactivity of halogens in displacement reactions?

What is the key characteristic of a precipitation reaction?

Which precipitate is formed when testing for sulfate ions?

What type of precipitate is formed when testing for halide ions?

What type of reaction occurs when dilute sulfuric acid is added to barium chloride?

What is the ionic equation for the reaction between hydrochloric acid and sodium hydroxide?

What color precipitate is typically formed from a lead iodide salt?

Which is the correct balanced equation for the reaction between zinc (Zn) and hydrochloric acid (HCl)?

What is the oxidation state of sulfur in sulfuric acid (H₂SO₄)?

Which of the following reactions does not produce a salt?

A student mixes two clear solutions, and a yellow solid immediately forms. Which of the following is the most likely type of reaction that has occurred?

A metal X is placed in an aqueous solution of metal nitrate YNO₃. Metal X replaces metal Y, forming XNO₃(aq) and solid Y. What can be concluded from this experiment?

When chlorine gas is bubbled through a solution of potassium iodide (KI), the solution turns brown. What is the brown substance formed in this reaction?

What volume of carbon dioxide, measured at room temperature and pressure (RTP), is produced when 0.05 moles of hydrochloric acid react completely with an excess of calcium carbonate? (Assume the molar volume of a gas at RTP is 24 dm³mol⁻¹)

Consider the precipitation reaction between silver nitrate ($AgNO_3$) and sodium chloride ($NaCl$). If $50.0 mL$ of $0.10 M$ $AgNO_3$ is mixed with $50.0 mL$ of $0.10 M$ $NaCl$, what mass of silver chloride ($AgCl$) will precipitate out of the solution? (Molar mass of $AgCl = 143.32 g/mol$)

A student performs a displacement reaction by adding 2.0 g of zinc powder to 100.0 mL of a 0.50 M copper(II) sulfate solution. Assuming the reaction goes to completion, what mass of copper will be produced? (Molar mass of Zn = 65.38 g/mol, Cu = 63.55 g/mol)

When excess dilute hydrochloric acid is reacted with 4.0 g of a metal carbonate, $MCO_3$, 960 cm³ of carbon dioxide is produced at room temperature and pressure (RTP). Assuming the molar volume of a gas is 24.0 dm³mol⁻¹ at RTP, identify the metal, M. (RAM : Mg = 24.3, Ca = 40.1, Sr = 87.6, Ba = 137.3)

A student is tasked with identifying an unknown metal halide salt. They dissolve the salt in water and add silver nitrate solution, resulting in a pale yellow precipitate. The precipitate is then exposed to concentrated ammonia solution, where it partially dissolves. Which halide anion is most likely present in the unknown salt?

A solution contains a mixture of chloride ($Cl^−$), bromide ($Br^−$), and iodide ($I^−$) ions. You want to selectively precipitate the silver halide salts one at a time using silver nitrate ($AgNO_3$). Given the solubility products ($K_{sp}$) of $AgCl = 1.8 × 10^{−10}$, $AgBr = 5.0 × 10^{−13}$, and $AgI = 8.3 × 10^{−17}$, which silver halide will precipitate first as $AgNO_3$ is added?

Aqueous lead(II) nitrate reacts with aqueous sodium chloride to form a precipitate. Considering a solution containing 0.1 M $Pb^{2+}$ and 0.2 M $Cl^-$, calculate the concentration of $Pb^{2+}$ ions remaining in solution at equilibrium. (The $K_{sp}$ for $PbCl_2$ is $1.6 × 10^{−5}$)