Chemistry 1.1 and 1.2 - greenhouse gases and photochemical smog

What are the main greenhouse gases

The main greenhouse gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O).

What do greenhouse gases do

They trap heat in the atmosphere, contributing to the greenhouse effect and global warming.

Harmful effects of the presence of ozone in the troposphere to humans

• damage the respiratory tract

• damage the lung tissue

• reducing the rate of diffusion

• reduce how much oxygen is absorbed

Harmful effects of the presence of ozone in the troposphere to plants

• gas enters stoma

• cause them to close

• limit gas exchange

• disrupts normal functions

• susceptible to extreme wealth conditions

What is photochemical smog and what are the main pollutants involved

Gaseous pollutants in environment. It forms in densely populated areas

These polutants include nitrogen oxides and ozone

What are the conditions of photochemical smog

• high concentration of pollutants

• sunlight/UV

• still air mass

• temperature inversion

How does nitric oxide form

N₂ + O₂ —> 2NO

This reaction occurs at high temperatures, such as in combustion engines and lightning strikes.

How does nitrogen dioxide form

2NO + O₂ —> 2NO₂

This reaction occurs when nitric oxide reacts with oxygen in the atmosphere, often in the presence of sunlight.

How does the presence of NO₂ lead to the formation of ozone

NO2 absorbs UV light, leading to the dissociation of nitrogen dioxide into nitric oxide (NO) and a free oxygen atom. This free oxygen atom can then react with molecular oxygen (O₂) to form ozone (O₃).

NO₂ —→ NO + O

O + O₂ —→ O₃

What are catalytic converters

Devices found in the exhaust of motor vehicles. They reduce the impacts of pollutants by converting them into less harmful products

How to catalytic converters work

They convert pollutants into less harmful products. They convert carbon monoxide, nitrogen oxides and unburnt hydrocarbons through redox reactions

What is a radical and what is an example

Eg oxygen radical

when an element is not in its naturally occurring form so it is highly reactive

O is a radical because it wants to be O₂

Why are nitrogen oxides formed in high temp engines and furnaces

For a nitrogen oxide to form, a nitrogen and oxygen needs to bond together. Nitrogen gas is bonded by a triple covalent bond, which is the strongest bond. High temps are needed to create enough energy for these bonds to break and the reaction to begin

How do you convert from mol L ^-1 to gL^-1?

multiply by the molar mass

How do you convert from gL^-1 to mol L ^-1 ?

divide by the molar mass

How do you convert from gL^-1 to mg L ^-1 ?

multiply by 1000

How do you convert from mg L ^-1 to gL^-1 ?

divide by 1000

what does ppm mean?

parts per million

What does ppb mean

parts per billion

What is the density formula

p=m/v

What is another way of saying density

The mass concentration

ppm to ppb

multiply by 1000

how to convert ppb to ppm

divide by 1000

What is the percentage composition formula