Chemical Formulae, Equations, the Mole and Gases
From the lesson
30 marksWhich equation is balanced?
Learners' Alley, Formulae, Equations, the Mole and Gases slides
Which sample contains the greatest number of atoms? (Ar: H 1.0, He 4.0, N 14.0, O 16.0)
Learners' Alley, Formulae, Equations, the Mole and Gases slides
2.0 mol of N2 reacts with 3.0 mol of H2: N2 + 3H2 → 2NH3. What is the greatest amount of NH3 that can form?
Learners' Alley, Formulae, Equations, the Mole and Gases slides
What volume of carbon dioxide, measured at room temperature and pressure, forms when 0.10 mol of propane, C3H8, burns completely?
Learners' Alley, Formulae, Equations, the Mole and Gases slides
Under which conditions does a gas behave most like an ideal gas?
Learners' Alley, Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Convert into SI units.
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Learners' Alley, Chemical Formulae, Equations, the Mole and Gases slides
Practice
17 marksThe relative atomic mass of naturally occurring chlorine is not a whole number. What is the reason for this?
2024 BLSS O Prelim P1 Q6
The element thallium, Tl, has only two isotopes with mass numbers 203 and 205. The relative abundance of Tl-203 is 30%. Which of the following is the relative atomic mass of thallium?
2024 Punggol O Prelim P1 Q6
A giant molecule contains a large amount of carbon-12 and carbon-13 isotopes. The average relative atomic mass of carbon in the giant molecule is 12.2. What proportion of carbon-12 atoms is present in the giant molecule?
2024 AES O Prelim P1 Q8
Element V has 14 neutrons and 13 protons, while element W has 10 neutrons and 9 protons in its nucleus. What would be the molar mass of the compound formed between V and W?
2024 SMSS O Sec3 P1 Q8
The rate of diffusion of two gases, methane, CH4, and propene, C3H6, is investigated. Which gas diffuses at a faster rate and why? Each option gives the faster gas, then the reason.
Source: 2024 SCGS O Prelim P1 Q2
Which substance has 7.2 × 1023 atoms?
2024 YSS O Prelim P1 Q11
An element forms a diatomic molecule, Q, which has a relative molecular mass, x. The Avogadro constant is L. How many atoms are present in 1.0 g of Q?
2025 TKGS O Prelim P1 Q14
A black solid, X, is an oxide of ruthenium. 5.79 g of X contains 1.39 g of oxygen. What is the empirical formula of X?
2024 Compassvale O Prelim P1 Q15
Aerials in portable radios are made of a mixture of the oxides of calcium and iron known as ‘ferrite’. It contains 18.5% calcium and 51.9% iron by mass. Which is the empirical formula of ‘ferrite’?
2024 NASS O Prelim P1-P2 Q14
The relative molecular mass, Mr, of liquid Z is 60. Z contains 40.0% carbon, 6.70% hydrogen and 53.3% oxygen. Which row shows the correct empirical and molecular formulae of Z?
| empirical formula | molecular formula | |
|---|---|---|
| A | CH2O | CH2O |
| B | CH2O | C2H4O2 |
| C | C2H4O2 | C2H4O2 |
| D | CH3O | C2H6O2 |
2024 Whitley O Prelim P1 Q11
On complete combustion, a sample of hydrocarbon gives 11.0 g of carbon dioxide and 9.0 g of water. What is the molecular formula of the hydrocarbon?
2022 HYSS O Prelim P1 Q10
When 4.8 g of magnesium is heated in a crucible, 5.9 g of magnesium oxide is formed. What is the percentage yield of magnesium oxide?
2024 CGS O Prelim P1 Q10
Ammonia and excess carbon dioxide can react to form urea and water: 2NH3 + CO2 → CON2H4 + H2O. The percentage yield of this reaction is 80%. What mass of ammonia is required to obtain 60.0 g of urea? [Mr: NH3 17, CO2 44, CON2H4 60, H2O 18]
2024 Bukit View O Prelim P1 Q16
When 42.0 g of sodium hydrogencarbonate, NaHCO3 (Mr = 84), was strongly heated, 3.00 dm3 of carbon dioxide gas, measured at room temperature and pressure, was released. 2NaHCO3 → Na2CO3 + H2O + CO2. What was the percentage yield of carbon dioxide?
2025 JYSS O Prelim P1 Q15
What is the concentration of iron(III) ions in 0.01 mol/dm3 of aqueous iron(III) sulfate?
2024 Serangoon O Prelim P1 Q19
28 g of gaseous hydrocarbon X has a volume of 12 dm3 at room temperature and pressure. What is the molecular formula of X?
2024 CCHY O Prelim P1-P2 Q16
Which fuel produces 144 dm3 of carbon dioxide, measured at room temperature and pressure, upon complete combustion?
2024 Zhonghua O Prelim P1 Q14
