Module Chemistry Essay Essay
Identify the steps In balancing a chemical equation To balance equation correctly using the proper way To write an analogy about balancing Lecture: A chemical equation describes what happens in a chemical reaction.
The equation identifies the reactants (starting materials) and products (resulting substance), the formulas of the participants, the phases of the participants (solid, liquid, gas), and the amount of each substance. Balancing a chemical equation refers to establishing the mathematical relationship between the quantity of reactants and products. The quantities are expressed as grams or moles.
Balancing equations is a fundamental skill in Chemistry. Steps in balancing equation: 1. Write the unbalanced equation.
Chemical formulas of reactants are listed on the elephant side of the equation. Products are listed on the rightward side of the equation. Reactants and products are separated by putting an arrow between them to show the direction of the reaction. Reactions at equilibrium will have arrows facing both directions.
2 Balance the equation. Apply the Law of Conservation of Mass to get the same number of atoms of every element on each side of the equation.
Tip: Start by balancing an element that appears in only one reactant and product. Once one element is balanced, proceed to balance another, and another, until all elements are balanced.
Balance chemical formulas by placing coefficients in front of them. Do not add subscripts, because this will change the formulas. 3 Indicate the states of matter of the reactants and products. Use (g) for gaseous substances.
Use (s) for solids. Use (l) for liquids. Use (as) for species in solution in water. Write the state of matter immediately following the formula of the substance it describes.
Let’s look at another example. If you use a gas stove to cook your dinner, chances are that your stove burns natural gas, which is primarily methane. Methane (CHI) is a molecule that contains four hydrogen atoms bonded to one carbon atom. When you light the stove, you are supplying deactivation energy to start the reaction of methane with oxygen in the air. During this reaction, chemical bonds break and re- form and the product’s are produced are carbon dioxide and water vapor (and, of course, light and heat that you see as the flame).
The unbalanced chemical equation loud be written: CHI(methane) + 02(oxygen) CA(carbon dioxide) + H2O(water) Look at the reaction atom by atom.
On the left side of the equation we find one carbon atom, and one on the right. Equation, but only two on the right. Water molecule (you can only change coefficients in a chemical equation, not subscripts). Adding this coefficient we get: What this equation now says is that two molecules of water are produced for every one molecule of methane consumed.
Moving on to the oxygenation, we find two on the left side of the equation, but a total of four on the right side (two from the
CA molecule and one from each of two water molecules H2O). Oxygen molecule on the left side of the equation, showing that two oxygen molecules are consumed for every one methane molecule that burns. Our Matter module). In essence, this law states that a chemical reaction always proceeds according to the ratio defined by the balanced chemical equation. Thus, you can interpret the balanced methane equation above as reading, “one part methane reacts with two parts oxygen to produce one part carbon dioxide and two parts water. ” This ratio always remains the same.
For example, if we start with two arts methane, then we will consume four parts 02 and generate two parts CA and four parts H2O. If we start with excess of any of the reactants (e. G. , five parts oxygen when only one part methane is available), the excess reactant will not be consumed: Excess reactants will not be consumed. In the example seen above, 302 had to be added to the right side of the equation to balance it and show that the excess oxygen is not consumed during the reaction. In this example, methane is called the limiting reactant.
Although we have discussed balancing equations in terms of numbers fathoms and molecules, keep in mind that we never talk about a single atom (or molecule) when we use chemical equations. This is because single atoms (and discussed in relation to the number of moles of reactants introduces used or produced Because the mole refers to a standard number of atoms (or molecules), the term can simply be substituted into chemical equations. Thus, the balanced methane equation above can also be interpreted as reading, “one mole of methane reacts with two moles of oxygen to produce one mole of carbon dioxide and two oleos of water. Conservation of matter The law of conservation of matter states that matter is neither lost nor gained in traditional chemical reactions; it simply changes form.
Thus, if we have a certain number of atoms of an element on the left side of an equation, we have to have the same number on the right side. This implies that mass is also conserved during a chemical reaction. The water reaction, for example: Activity 1 . Answer the following below AH 1 . What number represents the Coefficient? 2.
What number represents the Subscript? 3. What element is represented by the letter “H”? 4. How many “He’s” do you have?