This page covers CAPF AC Basic Concepts of Chemistry with complete concept notes, 16 graded practice MCQs, key points and exam-specific tips. Free to study.
According to the modern atomic theory, atoms of the same element must have the same number of:
Practice 2easy
What is the empirical formula of a compound containing 40% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?
Practice 3easy
What is the SI unit of amount of substance?
Practice 4easy
How many significant figures are present in the measurement 0.00450 kg?
Practice 5easy
If 2.0 moles of oxygen gas (O₂) react completely with hydrogen to form water, how many moles of water are produced? (2H₂ + O₂ → 2H₂O)
Practice 6medium
When 2.4 g of carbon completely burns in oxygen, how many moles of CO₂ are produced? (Atomic mass: C = 12, O = 16)
Practice 7medium
If 5 moles of H₂ react with 2.5 moles of O₂ according to 2H₂ + O₂ → 2H₂O, which reactant is limiting?
Practice 8medium
Which of the following statements best defines the mole concept in chemistry?
Practice 9medium
What is the empirical formula of a compound that contains 40% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?
Practice 10medium
Which of the following represents the correct relationship between molarity and molality for a dilute aqueous solution?
Practice 11medium
What is the oxidation state of sulfur in the compound H₂SO₄?
Practice 12medium
A solution has a pH of 3. What is its hydrogen ion concentration [H⁺] in mol/L?
Practice 13medium
Which law states that the total pressure of a mixture of gases is equal to the sum of partial pressures of individual gases?
Practice 14hard
A sample contains 3.011 × 10²³ atoms of carbon. Calculate the mass of carbon in grams. (Atomic mass of C = 12 u, Avogadro's number = 6.022 × 10²³)
Practice 15hard
Which of the following correctly represents the relationship between molarity (M), molality (m), and density (d) for a solution?
Practice 16hard
An element has an electron configuration of [Ar] 3d⁵ 4s². Its position in the periodic table and the number of unpaired electrons in the ground state are: