Wet Chemistry Lab

The Wet Chemistry Lab tests soil for pH, Salinity, Ethane, Methane, Carbon Dioxide, Water and Perchlorates.


pH is the measure of how acidic or basic (alkaline) a compound is. The pH scale runs from 1 to14, with 7 being neutral ('pure' water), 1 highly acidic (battery acid), and 14 highly basic (drain cleaner). Most crops need a soil pH between 6-8 for healthy growth, though some bacteria can live in extremely acidic environments with a pH of 3.8, and are classified as extremophiles.


Salinity is the amount of salt (by weight) dissolved in water, or soil.

Fresh water suitable for drinking contains less than 500 parts per million (ppm), and seawater around 35,000 ppm (3.5% salt). Salt lakes on Earth can reach a saturation point of 35% (10 times saltier than seawater), where salt-loving microorganisms called halophiles thrive. (see extremophiles above).

Fresh Water Brackish Water Saline Water Brine

< 0.5 0.5-30 30-50 > 50



  • Indirect evidence of methane.

Chemical structure: Ethane is made of two carbon (C) and six hydrogen (H) atoms. Chemical formula CH6. It is an odourless, colourless gas.


  • Forms naturally in natural gas on Earth

  • It can also be created in the atmosphere when UV radiation enables methane molecules to break down and then re-connect to form ethane.


Importance: Possible evidence of life.

Analysis: A single carbon atom surrounded by four hydrogen atoms, CH4. Methane is a colourless and odourless gas.

Formation / destruction:

  • Formed by anaerobic bacteria during respiration.

  • Also formed in the decomposition of living organisms

  • Breaks down in the martian atmosphere in less than a year.

Methane has been detected on Mars, and according to researchers there are two plausible theories - either their are microorganisms living in the Martian soil that are producing gas, or methane is being produced during reactions between volcanic rock and water.

Carbon Dioxide


  • 95% of Mars' atmosphere

  • All of the ice at the martian South Pole

  • Most of the ice at the North Pole

Chemical composition: Carbon dioxide is composed of one Carbon atom and two Oxygen atoms, CO2.

Formation: The carbon dioxide in Mars' atmosphere is mostly a remnant of the original atmosphere from when Mars was formed. Some carbon dioxide may have been released from volcanoes.



  • Possible location for life

  • All living organisms need water to survive

Chemical composition: Water is composed of two Hydrogen atoms and one Oxygen atom, H2O.

Formation: Scientists are uncertain whether water came from comets during the formation of the Solar System, or was released from rocks through volcanoes.



  • a possible source of energy for long term Mars colonisation.

  • Strong evidence for absence of liquid water.

Chemical composition: One Chlorine (Cl) atom bonded to four Hydrogens (H) atoms bonded with other compounds such as Nitronium (NO2), fluorine (Fl), ammonia (NH3), calcium (Ca), lithium (Li), potassium (K) and Sodium (Na).

Formation: Soils with high concentrations of natural salts can have some of their chloride converted to perchlorate in the presence of sunlight and/or ultraviolet light.


  • very dry deserts

  • very low temperature regions

Perchlorates were found on the surface of Mars by the Viking Lander in 1976 and then later by the Polar Lander in 2009.