chemical equations Flashcards
what are reactants?
the substances that undergo changes during a chemical reaction in order to obtain new substances or different substances.
what is a chemical equation?
a chemical equation is a symbolic representation of chemical reactions, it displays it in a concise manner with its proper reactants, products and relative amounts.
a typical chemical equation begins with reactants on the left side of the arrow and products to the right.
example: Magnesium + oxygen → magnesium oxide
what are products?
the new substances obtained after a chemical reaction are known as products.
what are balanced equations ?
this concept was bought out by Antoine L. Lavoisier, it is an equation in which the number of atoms and the total mass of product obtained is equal to that of reactants.
write the rules for balancing an equation.
the rules for balancing an equation are as follows: -
. we cannot alter the formulas of compounds or elements in the reactions.
. use coefficients instead of subscript.
. start with complex compounds.
. balance hydrogen and oxygen at last.
. balance metals and non-metals sequentially.
why should magnesium ribbon be cleaned before burning in air?
the magnesium ribbon is cleaned so as to remove any oxide layer forming on it surface. magnesium and oxygen react together to form magnesium oxide, any other layer on the surface f the ribbon can slow down the combustion reaction.
what are combustion reactions?
it is a reaction in which a substance reacts rapidly with oxygen by releasing heat and light. normally fuel reacts with oxygen to form carbon dioxide and water along with energy in form of heat or/and light.
write the factors for determination of a chemical reaction.
there are mainly three changes occurring after a chemical reaction they are as follows: -
a) change in state
b) change in color
c) change in temperature
d) evolution of gas
