CHEM PRAC TERMS

VALID

Valid experiment is one that successful tests the aim and the hypothesis. A valid extremity is testing what it claims to be testing.

 

A valid experiment only changes the IV and controls all other variables, to ensure that it is only testing the effect of the IV on the DV

Valid measurement

A valid results is one that measures what is claims to be measuring.

ACCURACY

An accurate measurement means that it is close to the true value (for what is being measured)

MEASUREMENT RESULT

A measurement result refers to the value obtained from an experiment or an observation, which signifies the outcome of the measurement process. A final result of the average of multiple results.

PRECISION

How closely set of measurement agree with each other . How close all the measurements/data points are with each other, the close they are the more precise. INDICATES RELIABILITY.

RANDOM ERROR

Unpredictable variations and fluctuations in the measurement and experiment process that cause the measurements/data to not be precise.

Random errors are reduced by repeating trials and taking an average

REPEATABILITY

Repeatability means results are consisted when the experiment is reoperated many times.

 

High repeatability means high precision of results.

Multiple trials allows you to test for repeatability.

REPRODUCABILITY

Reproducibility means that the results are consistent/close when the same experiment is carried out under different conditions/person/time.

TRUE VALUE

The value that would be obtained if the experiment was conducted perfectly. This is often found via calculations on paper(using faradays law)

SYTEMAITC ERROR

Errors during the experiment that cause a consistent shift of the measurement/data in the same direction away from the true value. It affects the accuracy. ACCURACY CANNOT BE IMPRPVED BY REPEATING EXRPEIMERNTS.

 

Often caused by calibration issues, or constant human things.

UNCERTAITNIYY

The doubt that exists about the result of any measurement, indicating the range within which the true value may lie. Lack of exact knowledge of the value being measured. That is acknowledging that the measurement may be not true or an estimation

Faradays first law

States that the quanity of charge that is passed through a cell is directioanlly proiprtion ot the mass of metal depsited at the cathode during electrilcysois. Q = M.

Faradays second law

In order to produce 1 mol of a metal, 1,2,3 or another whole number of moles of an eletcros muste be consumed

Q = ne x e.

electrolysis

the prcoess of using electricity to drive non spontanous redox reactions via an external power sources and a conductive elctrolyte. converts electrical enery into chemcial energy.