[10] Gases in the atmosphere

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

78% nitrogen
21% oxygen
0.93% argon and other noble gases
0.04% carbon dioxide
variable amounts of water vapour
variable amounts of pollutant gases

how can you determine the percentage by volume of oxygen in air using experiments involving the reactions of metals e.g. copper with air

• 100 cm³ of air is passed repeatedly over heated copper filings in a glass tube, using two gas syringes.

• The copper reacts with the oxygen to form black copper(II) oxide.

• The volume of gas decreases as oxygen is removed.

• Heating continues until no further volume change occurs. The final volume is recorded

• the percentage of oxygen is calculated using the formula initial volume - final volume/initial volume or air x 100

How can you determine the percentage by volume of oxygen in air using experiments involving the reactions of non-metals with air?

Phosphorus reacts with oxygen to form phosphorus pentoxide. The decrease in volume of oxygen can be measured, allowing you to calculate the percentage of oxygen in air.

What happens when magnesium burns in oxygen? WHAT IS THE BALANCED CHEMICAL EQUATION

When magnesium burns in oxygen, it reacts to form magnesium oxide (MgO). The reaction is exothermic, producing a bright white flame.

2Mg+O₂​→2MgO

What happens when hydrogen burns in oxygen? GIVE THE CHEMICAL BALANCED EQUATION

When hydrogen burns in oxygen, it reacts to form water (H₂O). The reaction is exothermic and produces a blue, flame.

2H₂​+O₂→2H₂​O

What happens when sulfur burns in oxygen? GIVE THE CHEMICAL BALANCED EQUATION TOO

When sulfur burns in oxygen, it forms sulfur dioxide (SO₂), a colorless gas. The reaction is exothermic and produces a blue flame.

S+O₂​→SO₂

What happens during the thermal decomposition of copper (II) carbonate? GIVE THE BALANCED CHEMICAL EQUATION

When copper (II) carbonate (CuCO₃) is heated, it decomposes to form copper (II) oxide (CuO) and carbon dioxide (CO₂).

CuCO₃​→CuO+CO₂

Why is carbon dioxide considered a greenhouse gas?

because it traps heat in the Earth's atmosphere, contributing to the greenhouse effect which leads to an increase in global temperatures

How does the increase in carbon dioxide contribute to climate change?

increases the greenhouse effect as more heat is trapped leading to a rise in global temperatures which contributes to climate change

What is the chemical reaction that occurs when copper reacts with oxygen in the air? (ADD STATE SYMBOLS)

2Cu_(s)+O₂​_(g)→2CuO_(s)