WeightliftingChemistry of chalk and MgCO3, explored through the sport of weightlifting

The sport of weightlifting can be traced back to ancient times; menwould test their strength by lifting, or trying to lift, heavy stones. The sport as we now recognise it originated in Germany in the 1800s and the International Weightlifting Federation (IWF) was founded in 1905.

An introduction to weightlifting

The lifters use chalk on their hands to aid gripping the bar and to removemoisture, which could cause the bar to slip. Chalk, a naturally occurringor manmade substance, is rich with chemistry and it is here that the link between chemistry and weightlifting can be found.

Weightlifting and the link to chemistry

Lawn Tennis – line boundaries of court

When the ball hits a boundary line it makes a cloud of dust,

natural chalk has mostly been replaced with titanium oxide.

Gymnastics & rock climbing – stop slipping

Similarly to the sport of weightlifting, chalk is applied to

hands, arms & legs to stop slipping and absorb moisture.

Natural chalk has mostly been replaced with magnesium

carbonate here.

Chalk in sport

Other uses include:

Small amounts are found in tooth paste,

as implements to write with on black

boards or for pavement drawings.

Other uses of chalk

Chalk is: A soft solid White (sometimes naturally coloured red)

Natural chalk is formed in the ground, it is: Porous sedimentary rock – can hold water A form of limestone Composed of the mineral calcite

The characteristics of chalk

The formation of natural chalk occurs under deep marine

conditions.

The gradual accumulation of very small calcite plates shed

from marine micro-organisms called coccolithophores causes

the formation of the chalk.

Natural chalk

Chalk is fairly resistant to erosion compared to clay, another substance

often associated with chalk.

When clay surrounding chalk is eroded steep cliffs can result. A good

example being the white cliffs of Dover.

The porous nature of chalk means that it can hold water – this can provide

a natural reservoir that releases water slowly in drought.

Natural chalk

Natural chalk has widely been replaced with a manmade chalk called

magnesium carbonate.

It has similar characteristics to chalk in that it is a white, soft solid.

The empirical formula of magnesium carbonate is MgCO3.

Manmade chalk

Magnesium carbonate, although used in sport, also has a range of

other uses which include being used in: flooring, fireproofing, fire

extinguishing, cosmetics, dusting powder, drying agents, and in

laxatives for loosening bowels.

Manmade chalk

Magnesium carbonate, although occurring naturally as a mineral, is

produced through a variety of methods industrially.

One way it can be produced is by mixing solutions of magnesium with

carbonate ions under an atmosphere of carbon dioxide.

Another way it can be produced is by exposing a magnesium hydroxide

slurry to carbon dioxide under pressure.

Manmade chalk

Chalk is widely used in sport and in weightlifting it is used to

stop the hands slipping. It helps to increase friction between

the hands and the bar.

Chalk is formed in deep marine conditions when produced

naturally.

Most applications of natural chalk in sport have been replaced

with manmade magnesium carbonate which has the empirical

formula: MgCO3

Summary

Magnesium carbonate is produced synthetically through

various chemical reactions which combine magnesium with

carbonate ions under an atmosphere of carbon dioxide, or

expose magnesium hydroxide slurry to carbon dioxide under

pressure.

Summary continued

1. Chalk, when occurring naturally in the ground, comes from a sedimentary rock. Name the sedimentary rock and two other sediments that are sometimes found in this layer of rock.

The sedimentary rock that chalk comes from is limestone and other sediments which sometimes occur in limestone include flint and chert.

2. How is natural chalk formed?

Chalk is formed under deep marine conditions from the gradual accumulation of very small calcite plates shed from marine micro-organisms.

Worksheet answers – Q1 & 2

3. Describe a chemical process used to manufacture magnesium carbonate.

Magnesium carbonate can be produced by combining magnesium with carbonate ions under an atmosphere of carbon dioxide.

or

Magnesium carbonate can be produced by exposing magnesium hydroxide slurry to carbon dioxide. This process needs to take place under pressure.

Worksheet answers – Q3

4. Name five uses of magnesium carbonate other than in sport.

Answers could include: Fire extinguisher composition Drying agent Cosmetics Dusting powder Laxatives Reinforcing agent for neoprene rubber Flooring

Worksheet answers – Q4