Mole concept Chemical Formulae Equations (Trial SPM)

What is the meaning of avogadro's number (Kelantan 2020, Q1)

• mass of one mole of a substance

• pressure of one mole of a substance

• number of particles in one mole of a substance

• volume occupied by one mole of gas

Which of the following shows the balanced chemical equation? (Kelantan 2020, Q20)

• H₂O₂ --> 2H₂O + O₂

• 2NaOH + H₂SO₄ --> Na₂SO₄ + H2O

• C₃H₈ + 5O₂ --> 3CO₂ + 4H₂O

• HNO₃ + CaCO₃ --> Ca(NO₃)₂ + CO₂ + H₂O

Diagram shows a box of aspirin which can relieve fever and pain. If the molecular formula of aspirin is C₉H_XO₄, determine the value of x. (SPMRSM 2020, Q20)

(a)  

Diagram 2 shows the apparatus set-up to determine the empirical formula of copper(II) oxide. The dry hydrogen gas must be flowed through the apparatus for several minutes before heating the copper(II) oxide. What is the reason for this action to be taken? (Terengganu 2020, Q15)

• To ensure all the copper(II) oxide has changed into copper.

• To prevent copper from reacting with air to form copper(II) oxide.

• To ensure all air has been removed so that explosion can be prevented.

• To prevent the water from flowing toward the hot porcelain dish and cracks the combustion tube.

Diagram shows the setup of apparatus to determine the empirical formula of oxide of metal X. What is X? (SBP 2020, Q9)

• Iron

• Lead

• Zinc

• Copper

Why carbon-12 was chosen as a reference standard for relative atomic mass and relative molecular mass? (Perak 2020, Q2)

• Carbon has three isotopes

• Carbon is non-metal element

• Carbon is a solid and easier to be handle

• Carbon is located in Group 14 in the Periodic Table of Elements

The molecular formula of sodium nitrate and magnesium chloride are NaNO3 and MgCl2 respectively. What is the molecular formula of magnesium nitrate? (Penang 2020, Q2)

• MgNO₂

• Mg(NO₃)₂

• Mg₂NO₃

• Mg₂(NO₂)₃

Which of the following gases contains 0.4 mol of atoms at room temperature and pressure?

[1 mol of gas occupies the volume of 24 dm³ at room temperature and pressure] (Perak, Q4)

• 4.8 dm³ He

• 4.8 dm³ H₂

• 4.8 dm³ SO₃

• 4.8 dm³ CO₂

A compound with formula XCO₃ has a relative formula mass of 125. What is the relative atomic mass of X? [Relative atomic mass of C = 12 and O = 16] (Perlis 2020, Q21)

• 24

• 40

• 59

• 65

Calculate the volume of carbon dioxide gas produced for a complete combustion of 30 g of ethane gas at STP. [Relative atomic mass: H = 1, C = 12, 1 molar volume 22.4 dm³ mol^-1 at STP] (Melaka 2020, Q44)

• 22.4 dm³

• 44.8 dm³

• 67.2 dm³

• 89.6 dm³