I. Introduction
Chemistry is the study of
the transformation of matter from one form to the other. These
transformations often occur as a result of the combination of two
different types of matter. The combination of different elements to form
compounds is governed by certain basic rules. These rules are referred to as
laws of chemical combination. There are five basic laws of chemical combination
that govern the chemical combinations of elements:
a. Law
of Conservation of Mass
In simple terms, this
law states that matter can neither be created nor destroyed. In other words, the
total mass, that is, the sum of mass of reacting mixture and the products
formed remains constant. Antoine Lavoisier gave this law in the year 1789
based on the data he obtained after carefully studying numerous combustion reactions.
b. Law
of Definite Proportions
Joseph Proust, a French
chemist stated that the proportion of elements by weight in a given compound
will always remain exactly the same. In simple terms we can say that,
irrespective of its source, origin or its quantity, the percent composition of
elements by weight in a given compound will always remain the same.
Objectives: The objective of this experiment is
for the students to be able to explain the laws of chemical changes through
experimentation.
II. Results and Discussion
A. Law of definite proportion
Weight of Magnesium Ribbon 0.10g
Weight of Crucible and Cover 30.09g
Weight of Crucible and Cover with ash 31.07g
Weight of ash 0.17g
Formula: Computation:
%Mg = weight of Mg ribbon x 100 %Mg = 0.10
x 100 = 58%
weight of ash MgO 0.17
%O =
100%-%Mg %O2
= 100% - 58% = 42%
Question:
Does the product or ash weigh more or less than the original magnesium ribbon?
Why?
The product weighs more than the
magnesium ribbon because magnesium and oxygen synthesizes when heated then the
oxygen’s mass will add to magnesium’s mass.
Equation:
2Mg + O2 à 2MgO
B.
Law
of conservation of mass
Weight of NaCl solution and beaker 47g
Weight of AgNO3 solution and graduated
cylinder g
Weight of AgNO3 solution and graduated
cylinder 110g
Weight of the two solutions &
containers 157g
Equation:
NaCl + AgNO3 à Na2NO3 + AgCl2
III.
Conclusion
An
element can neither be created nor destroyed, therefore, an element cannot be
divided but only combined. Because they don’t divide, the mass of a certain
atom will always be the same even if you will do combine it with another atom.
The compound will derive a mass that come from the added masses of the
compound/molecules component.
IV.
References
Abayon,
Ester O. Integrated & Inorganic Chemistry
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