chapter 2: measurement and experimental techniques Flashcards
what is used for measuring mass? and what are the SI units for mass?
electronic balance (+- 0.01 - two dp) and beam balance
- kilogram
- grams ( smaller masses)
- tonne ( masses of heavy objects)
1000g = 1kg 1000kg = 1t
what is the difference between the analogue stopwatch and the digital stopwatch?
- analogue stopwatch: +- 0.1s
- digital stopwatch: +- 0.01s
what are the SI units for temperature and what are they measured by?
- Kelvin (K) and degree Celcius (°C)
- they are measured by a mercury thermometer and an alcohol thermometer
> with accuracy of +- 0.5°C - for more accurate readings, temperature sensor can be connected to a data logger
what is the SI unit for volume?
- cubic metre & cubic centimetre & cubic decimetre
- 1 mᶟ = 1000 dm³
- 1dm³= 1000 cm3
what do you call the curved surface formed when a solution is placed in a container?
a meniscus
what is the maximum volume a gas syringe can measure?
100cm3
what is displacement of water suitable for and what are some examples?
- water displacement method is suitable for collecting gases that are insoluble or slightly soluble in water
- eg: hydrogen, oxygen and carbon dioxide
what is downward delivery used for and what are some examples?
- it is used for gases that are soluble in water and denser than air
- eg: chlorine, hydrogen chloride, sulfur dioxide
what is upward delivery used for and what are some examples?
it is used for gases soluble in water and also less dense than air
- eg: ammonia
what are the three drying agents and what gases can they be used on?
- fused calcium chloride (Neutral)
- can be used to dry most gases
- quicklime (calcium oxide) - alkaline
- is used to dry ammonia
- concentrated sulfuric acid ( acid)
- can be used on chlorine and hydrogen chloride or sulfur dioxide
arrange the 7 gases that you need to know from not soluble to most soluble.
- hydrogen
- oxygen
- carbon dioxide
- chlorine
- hydrogen chloride, sulfur dioxide
- ammonia
