Introduction
Weighing is the process through which the mass of an object is determined by the use of a balance, for example the analytical balance. This balance is used for the purposes of measuring gravitational mass in the laboratory. Weight on the other is measured by the use of a spring balance. The analytical precision of using balances is to achieve accurate measurements of masses and weights in the lab so as to consequently achieve the desired results in the experiments being conducted.
Accurate Reading on an analytical Balance
The features of an electronic balance
Analytical procedures for most analyses involve weighing; which is in turn a usual source of errors that lead to the failure of obtaining the required analytical results. An analytical balance often used in the lab is the electronic balance. Its features make it desirable in the weighing of objects. This balance is easy to use due to the fact that it is developed to suit the learning capacity of students. It can accurately and precisely provide weights of masses in a relatively less time, thereby favoring the time taken in weighing samples. This balance is therefore reliable to both students and instructors. Its rugged nature allows for easy administration of objects to be weighed and consequently displays the masses weighed, sensitive to as less as 0.001g (Joesten, 2007).
The importance of the ability to 'tare' when weighting
Apart from the balances’ features, another aspect that tailors accurate readings from the balance is the ability tare when weighing. The importance of tare when weighing helps in the determination of net weight. What this implies for the laboratory activities is that the mass of the container that holds the object being weighed is deducted from the gross mass read from the balance in order to determine the net weight or mass of the object.
The difference between weigh boats and weigh paper and when to use each
Other apparatus that aid in the weighing process are the weigh boats and weigh papers. Weigh boats are square-shaped containers that are used samples that are liquid or solid in nature. They are used when a controlled pour-off is required because of their recessed corners. Weigh papers on the hand are used when weighing solid objects which do not necessary need controlled pouring like it is the case with liquids.
The Scoopula and its use
Transfer of solids in the lab during weighing is done using the scoopula (Joesten, 2007). Handling of solids from containers to the balances or from one place to another is done using this apparatus.
The difference in how you weigh micro and macro samples
Weighing micro and macro samples in the lab also determine the precision and accuracy of the process. Micro relates to small samples while on the other hand macro relates to large samples of objects to be weighed. The difference in measuring the two occurs in the context of the balances used, where the lesser the object to be measured, the complex the balance.
After weighing, is it a good idea to put chemicals back into their original containers? Explain why or why not.
After weighing has been done, chemicals are returned to their original containers (Joesten, 2007). This is done to ensure that the chemicals remain natural to the contents they should contain, by preventing them from reacting with components in the open air or foreign containers.
Definition of Terms
Accuracy – This is the state or quality of closeness between an obtained result and what is actually expected.
Precision – This refers to the degree of closeness of measured values, not necessarily in relationship to what is expected.
Tare – This is the weight of an empty weighing or measuring container, for example a weigh paper or a weigh boat.
Reference
Joesten, M. & Wood, J. (2007). World of Chemistry Essentials, 4th ed.: Thomson: Brooks/ Cole.
