General + Practical knowledge Flashcards
(38 cards)
How accurate should calculations be?
As accurate as your least accurate measurement
How many grams are in a tonne?
1,000,000
What does volatile mean?
Easily evaporated at normal temperatures
How do you convert degrees Celsius into kelvin?
Add 273
What is a colorimeter?
It measures colour
What is mmol?
It is a milimole
It is 1/1000 of a mole
What is the formula for percentage uncertainty?
Uncertainty in the value
———————— X 100
Value
How do you work out percentage uncertainty?
Add all of the individual uncertainties together
Define accuracy
A value that is considered to be close to the true value
Define random error
Something that can not be predicted
Define systematic error
An error in a piece of equipment
Define interval
The quantity between readings
Define repeatable
The original scientist using the same method and equipment, then getting the same result
Define reproducible
Different people using different equipment to get the same results
Define validity
The suitability of the plan that you have put together to answer the question
What is a catagoric variable?
A named variable
What is a continuous variable?
A variable with a value
What is a control variable?
A variable that is kept constant
What are dependent variables?
They are the results gained from changing the independent variable
What are independent variables?
The variables that you change
What are the rules of electrolysis?
DC power supply connected to two rods (electrodes)
Dissolved in an electrolyte, something able to conduct electricity
Cathode: negative current, cations (positive ions) are attracted to it, reduction
Anode: positive current, anions (negative ions) are attracted to it, oxidation
How do you determine the products of electrolysis at each electrode?
The most reactive element will be produced
What is an alkyl group?
A hydrocarbon with one hydrocarbon missing
Ends in -thyl
How do you convert parts per million into a percentage?
1ppm = 0.0001%
Divide by 10,000
