Edexcel IGCSE Chemistry: Gases in the Atmosphere

These flashcards cover key concepts related to gases in the atmosphere including chemical reactions, combustion, and the greenhouse effect.

What are the approximate percentages by volume of the four most abundant gases in dry air?

78% nitrogen, 21% oxygen, 0.9% argon, and 0.037% carbon dioxide.

How can the percentage by volume of oxygen in air be determined using copper?

By passing 100 cm³ of air over heated copper in a closed system until the volume stops decreasing, showing 21 cm³ of oxygen was used.

What is the reaction when copper reacts with oxygen?

2Cu (s) + O2 (g) -> CuO (s) where copper and oxygen react to form copper (II) oxide.

What is combustion, and how does it relate to oxidation?

Combustion is an oxidation reaction where a substance gains oxygen.

Write the reaction for magnesium burning in oxygen.

2Mg + O2 -> 2MgO, producing magnesium oxide.

What is produced when sulfur burns in oxygen?

Sulfur dioxide: S + O2 -> SO2.

What is the result of hydrogen burning in oxygen?

Water: 2H2 + O2 -> 2H2O.

What is the thermal decomposition of metal carbonates?

Metal carbonate (heat) -> metal oxide + carbon dioxide, e.g., CuCO3 -> CuO + CO2.

What role does carbon dioxide play in the atmosphere?

Carbon dioxide is a greenhouse gas that contributes to climate change.

Describe the greenhouse gas effect.

Greenhouse gases absorb infrared radiation from the Earth's surface, warming the atmosphere.

What causes global warming?

An increase in greenhouse gases, leading to an enhanced greenhouse effect and a rise in average global temperatures.