Tuesday, 13 August 2013

1.2 Collection of gases

All gases have different types of properties. Some gases are heaver and lighter than the air around us. Heavier gases fall down and do not rise. Lighter gases rise up because they have a lower density than the air around us. For ex. Hot air balloons rise up because of the hot air made from the fire below the balloon makes a gas which is light which cause the balloon to rise.


  • Ammonia gas - It is colorless , it is light(compared to air),extremely soluble(In Water) 
  • Carbon dioxide gas - It is colorless , it is heavier(compared to air),slightly soluble(In Water) 
  • chlorine gas - It is green/yellow , it is much heavier(compared to air),extremely soluble(In Water) 
  • Hydrogen chloride gas - It is colorless , it is slightly heavier(compared to air),very soluble(In Water) 
  • Hydrogen gas - It is colorless , it is much lighter(compared to air),extremely soluble(In Water) 
  • Oxygen gas - It is colorless , it is the same(compared to air),slightly soluble(In Water) 





If it is a light gas  then we will use upward delivery because light gas rises up. If it is a heavy gas like carbon dioxide the it will fall down so we will use downward delivery.
















Measurements:

kilogram             -base unit for mass
volume of a cube-determined by its length cubed
m cubed             -si unit for volume




Monday, 12 August 2013

Unit 1

Experimental Chemistry

1.1 Measurement: Mass, Volume,Time,Temperature

Mass and Volume

Mass is how much matter an object has. Every thing in chemistry has to be precises. So we use typical beam balance and electronic beam balance to measure mass of an object. Most accurate at this time is electron beam balance which can measure   the mass up to 3 decimal points.

glass of water
The amount of water this glass has is the volume
Volume is the amount of space a substance occupies. For ex. a glass containing water.The amount of space the water occupies is the volume.  
electronic beam balance
This is a electronic balance










typical beam balance
This is a typical beam balance





To measure volume we use the following apparatus:

  • Beaker- It is a simple container for stirring, mixing and heating liquids commonly used in many laboratories. Beakers are generally cylindrical in shape, with a flat bottom.[1] Most also have a small spout (or "beak") to aid pouring as shown in the picture. Beakers are available in a wide range of sizes, from one milliliter up to several liters.
  • Burette-  It is a device used in analytic chemistry for the dispensing of variable, measured amounts of a chemical solution. It is accurate to the nearest 0.1 cm cubed.
  • Measuring cylinder- It is a piece of laboratory equipment used to measure the volume of a liquid. It can measure to the nearest cm cubed.
  • Pipette- It is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid. It can measure up to 10 cm cubed and 25 cm cubed.
  • Volumentric Flask- It is a piece of laboratory glassware, a type of laboratory flask, calibrated to contain a precise volume at a particular temperature. It can measure exactly 100 cm cubed, 250 cm cubed, and 1 dm cubed.
  • plastic syringe- Measures small volumes of liquids.
  • Gas syringe - It is usually made of glass. It can be used to measure gaseous products from a reaction.




Time and Temperature
Time can be measured by stopwatch or stopclock. Temperature can be measured using a thermometer.Temperature can be measured in Celsius, Fahrenheit, and kelvin. The SI unit for temperature is Kelvin.