Explain how the attractive forces between the particles in a liquid are related to the equilibirum vapour pressure of that liquid.

Attractive forces between particles are inversely proportional to vapour pressure.

Explanation:

Inside a liquid, molecules undergo random motion (thermal motion), but also interact with one another via electromagnetic forces of different kinds, like Van der Waals forces, ion-dipole interactions, hydrogen bonds, etc. These forces keep the liquid together, giving it a definite volume, in distinction to gases, which take the volume of the vessel that contains them.

Now, some molecules in a liquid can attain a high velocity as a random outcome of thermal motion, if this molecule is at the liquid's surface, it might actually escape! actually, many molecules might do that, and form a vapour over the liquid's surface.

Now, we know that liquids exist, therefore this process has to reach an equilibrium, that means, once the vapour becomes dense (or concentrated) enough, it would be as likely for a vapour molecule to re-enter the liquid as it is likely for a liquid molecule to leave the liquid and enter into the vapour.

This is called vapour-liquid equilibrium.  

How can we measure how "concentrated" the vapour is? by measuring the pressure above the liquid. We know by the ideal gas law that the number of molecules in a gas is proportional to pressure at constant volume and temperature.

But how does vapour pressure relate to intermolecular forces?

Simply, the stronger the intermolecular forces, the less likely a molecule at the liquid's boundary will be to shoot of into the vapour phase! and viceversa, if intermolecular forces are very weak, the molecules won't hold together much and many molecules will leave the liquid.

As an extreme case imagine a solid, for which intermolecular forces are the strongest, what's the vapour pressure of a solid? Do solids evaporate into the air?  The answer is no, solids (with few exceptions) don't evaporate, and their vapour pressure is extremely small.

Cheers!

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the capital city of australia is canberra.

according to the u.s. department of agriculture, the label of "certified organic" comes with a set of highly regulated standards for environmental stewardship and resource conservation. some of these include maintenance and improvement of soil quality, prevention of ground and surface water contamination, greenhouse gas regulation, encouragement of biodiversity and conservation of water and energy (see references 1). organic practices integrate natural methods such as mulching, plant diversity, native and adapted plants, crop rotation and the introduction of beneficial insects to control pests without synthetic pesticides.

environmental implications of pesticides

synthetic pesticides ensure high crop yields. while effective in achieving this goal, pesticides contaminate soil, air, ground and surface water, as well as the plants and animals that come into contact with these contaminated sources. freshwater and marine organisms are particularly susceptible to pesticides through agricultural runoff. pesticides also reduce soil fertility (necessitating the use of synthetic fertilizers) and can travel far from the original source, contaminating water and air hundreds of miles from the location of application (see references 2).

health implications of organics

although a subject of particular debate, many recent findings show that organic food is healthier than conventionally grown food. according to the usda, an extensive european union-funded study found that organically grown foods contain more beneficial compounds, such as the vitamins and antioxidants needed to combat many diseases (see references 5). organic milk, meat and eggs are regulated to ensure they are free of hormones administered to conventional livestock and poultry.

health implications of pesticides

pesticides affect human health in three ways: through skin contact, inhalation and ingestion. acute and long-term exposure to pesticides can cause serious health problems for farmers who apply them. the majority of other people are affected by drinking contaminated water and eating contaminated marine life (see references 3). pesticides have been linked to neurological disorders, endocrine and reproductive disorders, immune system deficiencies and cancer. according to the world health organization, acute pesticide poisoning (app) is responsible for significant annual mortality, especially in developing nations (see references 4).

other important considerations

not every small farm or business owner can afford the costly certification process required to be considered "certified organic," even if the farm is not using chemicals. "transitional" farms include those that once used chemicals and are now transitioning to organic-only production. in addition, though organic farming methods offer obvious environmental benefit, an organic apple shipped from around the world creates a different set of environmental problems. locally grown food (particularly locally grown, organic food) is key in sustainable food production.