Post by Jack Hewitt 2H » Fri Dec 07, am Madelyn Cearlock wrote: For the question that asks why do we balance chemical equations, what was the exact answer that was desired? Post by duenezjuleny1D » Wed Jun 26, pm We want to make sure not break the law of conservation of mass.
It is important to balance on each side, the products and the reactants. Post by Brian Kwak 1D » Wed Jun 26, pm It is because of the concept of conservation of mass which states that in an isolated system mass can not be created nor destroyed by chemical reactions or physical transformations. Since the chemical reaction can not destroy or create mass the number of elements from the reactants must equal the number of elements that are produced.
Also my TA said not to assume every chemical equation we get on the exam will be balanced. He said to verify everytime we are presented with an equation to check ourselves that it is balanced. Post by Karolina herrera1F » Sat Jun 29, pm This would be to show the conservation of mass a chemical equation must have an equal number of each type of atoms on both sides of the reaction arrow.
Post by Joanne Lee 1J » Wed Oct 02, am According to the law of conservation of mass, during a chemical reaction, mass is neither created or destroyed so the equation must be balanced in order to follow this law. Jump to. If you compare the unbalanced equation to the balanced equation, you will see that the chemical formulas of each reactant and product were not changed.
The only change is the coefficient of 2 written in front of the formula for oxygen on the reactant side, and the coefficient of 2 written in front of the formula for water on the product side. So now there are one carbon atom, four hydrogen atoms, and four oxygen atoms on both sides of the equation, and the equation is balanced.
Now the equation says that "One molecule of methane plus two molecules of oxygen produce one molecule of carbon dioxide and two molecules of water". When working with moles, the equation would be read as "One mole of methane plus two moles of oxygen produce one mole of carbon dioxide and two moles of water". Here is a video which discusses the importance of balancing a chemical equation.
Video from: Noel Pauller. Why do chemical equations need to be balanced? Aug 22, Related questions When balancing equations, which numbers are you allowed to change? Chemical equations are symbolic representations of chemical and physical changes. Formulas for the substances undergoing the change reactants and substances generated by the change products are separated by an arrow and preceded by integer coefficients indicating their relative numbers. Balanced equations are those whose coefficients result in equal numbers of atoms for each element in the reactants and products.
Chemical reactions in aqueous solution that involve ionic reactants or products may be represented more realistically by complete ionic equations and, more succinctly, by net ionic equations.
An equation is balanced when the same number of each element is represented on the reactant and product sides. Equations must be balanced to accurately reflect the law of conservation of matter. Skip to main content. Chemical Reactions. Search for:. Writing and Balancing Chemical Equations Learning Objectives By the end of this section, you will be able to: Derive chemical equations from narrative descriptions of chemical reactions.
Write and balance chemical equations in molecular, total ionic, and net ionic formats. Example 1: Balancing Chemical Equations Write a balanced equation for the reaction of molecular nitrogen N 2 and oxygen O 2 to form dinitrogen pentoxide. Element Reactants Products Balanced? Use this interactive PhET tutorial for additional practice balancing equations. Example 2: Molecular and Ionic Equations When carbon dioxide is dissolved in an aqueous solution of sodium hydroxide, the mixture reacts to yield aqueous sodium carbonate and liquid water.
Key Concepts and Summary Chemical equations are symbolic representations of chemical and physical changes. Exercises What does it mean to say an equation is balanced? Why is it important for an equation to be balanced? Consider molecular, complete ionic, and net ionic equations. What is the difference between these types of equations? In what circumstance would the complete and net ionic equations for a reaction be identical?
Write a balanced molecular equation describing each of the following chemical reactions. Solid calcium carbonate is heated and decomposes to solid calcium oxide and carbon dioxide gas. Gaseous butane, C 4 H 10 , reacts with diatomic oxygen gas to yield gaseous carbon dioxide and water vapor.
Aqueous solutions of magnesium chloride and sodium hydroxide react to produce solid magnesium hydroxide and aqueous sodium chloride. Water vapor reacts with sodium metal to produce solid sodium hydroxide and hydrogen gas. Write a balanced equation describing each of the following chemical reactions. Solid potassium chlorate, KClO 3 , decomposes to form solid potassium chloride and diatomic oxygen gas. Solid aluminum metal reacts with solid diatomic iodine to form solid Al 2 I 6.
When solid sodium chloride is added to aqueous sulfuric acid, hydrogen chloride gas and aqueous sodium sulfate are produced. Aqueous solutions of phosphoric acid and potassium hydroxide react to produce aqueous potassium dihydrogen phosphate and liquid water. Colorful fireworks often involve the decomposition of barium nitrate and potassium chlorate and the reaction of the metals magnesium, aluminum, and iron with oxygen.
Write the formulas of barium nitrate and potassium chlorate. The decomposition of solid potassium chlorate leads to the formation of solid potassium chloride and diatomic oxygen gas.
Write an equation for the reaction. The decomposition of solid barium nitrate leads to the formation of solid barium oxide, diatomic nitrogen gas, and diatomic oxygen gas.
Write separate equations for the reactions of the solid metals magnesium, aluminum, and iron with diatomic oxygen gas to yield the corresponding metal oxides. Fill in the blank with a single chemical formula for a covalent compound that will balance the equation: Aqueous hydrogen fluoride hydrofluoric acid is used to etch glass and to analyze minerals for their silicon content.
Hydrogen fluoride will also react with sand silicon dioxide.
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