Which balanced equation represents a single replacement reaction

Here is a real world example to show how stoichiometric factors are useful. There are 12 party invitations and 20 stamps. Each party invitation needs 2 stamps to be sent. How many party invitations can be sent?

In this example are all the reactants stamps and invitations used up? No, and this is normally the case with chemical reactions. There is often excess of one of the reactants. The limiting reagent, the one that runs out first, prevents the reaction from continuing and determines the maximum amount of product that can be formed. What is the limiting reagent in this example?

Stamps, because there was only enough to send out invitations, whereas there were enough invitations for 12 complete party invitations. Aside from just looking at the problem, the problem can be solved using stoichiometric factors. When there is no limiting reagent because the ratio of all the reactants caused them to run out at the same time, it is known as stoichiometric proportions.

Before applying stoichiometric factors to chemical equations, you need to understand molar mass. Molar mass is a useful chemical ratio between mass and moles. The atomic mass of each individual element as listed in the periodic table established this relationship for atoms or ions.

For compounds or molecules, you have to take the sum of the atomic mass times the number of each atom in order to determine the molar mass. Using molar mass and coefficient factors, it is possible to convert mass of reactants to mass of products or vice versa. Almost every quantitative relationship can be converted into a ratio that can be useful in data analysis. This ratio can be useful in determining the volume of a solution, given the mass or useful in finding the mass given the volume.

In the latter case, the inverse relationship would be used. Percents establish a relationship as well. A percent mass states how many grams of a mixture are of a certain element or molecule. This is useful in determining mass of a desired substance in a molecule. If the total mass of the substance is 10 grams, what is the mass of carbon in the sample?

How many moles of carbon are there? Given volume and molarity, it is possible to calculate mole or use moles and molarity to calculate volume. This is useful in chemical equations and dilutions. These ratios of molarity, density, and mass percent are useful in complex examples ahead. An empirical formula can be determined through chemical stoichiometry by determining which elements are present in the molecule and in what ratio.

The ratio of elements is determined by comparing the number of moles of each element present. It yields 0. What is the empirical formula of the organic molecule? This is a combustion reaction. The problem requires that you know that organic molecules consist of some combination of carbon, hydrogen, and oxygen elements. With that in mind, write the chemical equation out, replacing unknown numbers with variables. Do not worry about coefficients here.

Since all the moles of C and H in CO 2 and H 2 O, respectively have to have came from the 1 gram sample of unknown, start by calculating how many moles of each element were present in the unknown sample. Calculate the final moles of oxygen by taking the sum of the moles of oxygen in CO 2 and H 2 O. This will give you the number of moles from both the unknown organic molecule and the O 2 so you must subtract the moles of oxygen transferred from the O 2.

Using the Law of Conservation, we know that the mass before a reaction must equal the mass after a reaction. With this we can use the difference of the final mass of products and initial mass of the unknown organic molecule to determine the mass of the O 2 reactant.

To determine a molecular formula, first determine the empirical formula for the compound as shown in the section above and then determine the molecular mass experimentally.

Next, divide the molecular mass by the molar mass of the empirical formula calculated by finding the sum the total atomic masses of all the elements in the empirical formula. Multiply the subscripts of the molecular formula by this answer to get the molecular formula.

In the example above, it was determined that the unknown molecule had an empirical formula of CH 2 O. Since 3. If the answer is not close to a whole number, there was either an error in the calculation of the empirical formula or a large error in the determination of the molecular mass.

Multiply the ratio from step 4 by the subscripts of the empirical formula to get the molecular formula.

Check your result by calculating the molar mass of the molecular formula and comparing it to the experimentally determined mass. The alloy's density is 3. One liter of alloy completely fills a mold of volume cm 3. He accidentally breaks off a 1.

Assuming the acid reacts with all the iron II and not with the copper, how many grams of H 2 g are released into the atmosphere because of the amateur's carelessness? Note that the situation is fiction. Step 1 : Write a balanced equation after determining the products and reactants. Step 3: Answer the question of what is being asked. The question asks how much H2 g was produced. You are expected to solve for the amount of product formed. Step 4: Start with the compound you know the most about and use given ratios to convert it to the desired compound.

Convert the given amount of alloy reactant to solve for the moles of Fe s reacted. The above conversion involves using multiple stoichiometric relationships from density, percent mass, and molar mass.

The balanced equation must now be used to convert moles of Fe s to moles of H 2 g. Remember that the balanced equation's coefficients state the stoichiometric factor or mole ratio of reactants and products.

The question asks for how many grams of H 2 g were released so the moles of H 2 g must still be converted to grams using the molar mass of H 2 g. Since there are two H in each H 2 , its molar mass is twice that of a single H atom. Stoichiometry and balanced equations make it possible to use one piece of information to calculate another. There are countless ways stoichiometry can be used in chemistry and everyday life. Try and see if you can use what you learned to solve the following problems.

Write the balanced chemical equation for this reaction. The unbalanced equation is provided below. It produces 1.

Knowing that all the carbon and hydrogen atoms in CO 2 and H 2 O came from the 0. Balancing In chemistry, chemical reactions are frequently written as an equation, using chemical symbols.

Reactants to Products A chemical equation is like a recipe for a reaction so it displays all the ingredients or terms of a chemical reaction. Stoichiometric Coefficients In a balanced reaction, both sides of the equation have the same number of elements.

A simple activity series is shown below. Using the activity series is similar to using the positions of the halogens on the periodic table. An element on top will replace an element below it in compounds undergoing a single-replacement reaction. Elements will not replace elements above them in compounds.

Use the activity series to predict the products, if any, of each equation. Use the activity series to predict the products, if any, of this equation. A double-replacement reaction occurs when parts of two ionic compounds are exchanged, making two new compounds. A characteristic of a double-replacement equation is that there are two compounds as reactants and two different compounds as products.

An example is. There are two equivalent ways of considering a double-replacement equation: either the cations are swapped, or the anions are swapped. You cannot swap both; you would end up with the same substances you started with.

Either perspective should allow you to predict the proper products, as long as you pair a cation with an anion and not a cation with a cation or an anion with an anion. Thinking about the reaction as either switching the cations or switching the anions, we would expect the products to be BaSO 4 and NaCl. Predicting whether a double-replacement reaction occurs is somewhat more difficult than predicting a single-replacement reaction.

However, there is one type of double-replacement reaction that we can predict: the precipitation reaction. A precipitation reaction occurs when two ionic compounds are dissolved in water and form a new ionic compound that does not dissolve; this new compound falls out of solution as a solid precipitate. The formation of a solid precipitate is the driving force that makes the reaction proceed. To judge whether double-replacement reactions will occur, we need to know what kinds of ionic compounds form precipitates.

For this, we use solubility rules , which are general statements that predict which ionic compounds dissolve are soluble and which do not are not soluble or insoluble.

Table 4. We need to consider each ionic compound both the reactants and the possible products in light of the solubility rules in Table 4. If a compound is soluble, we use the aq label with it, indicating it dissolves. If a compound is not soluble, we use the s label with it and assume that it will precipitate out of solution. If everything is soluble, then no reaction will be expected. Are these soluble?

NaCl is by the same rule we just quoted , but what about SrSO 4? Therefore, we expect a reaction to occur, and the balanced chemical equation would be. You would expect to see a visual change corresponding to SrSO 4 precipitating out of solution Figure 4. Some double-replacement reactions are obvious because you can see a solid precipitate coming out of solution. Will a double-replacement reaction occur? If we assume that a double-replacement reaction may occur, we need to consider the possible products, which would be NaCl and Fe OH 2.

NaCl is soluble, but, according to the solubility rules, Fe OH 2 is not. Therefore, a reaction would occur, and Fe OH 2 s would precipitate out of solution. The balanced chemical equation is. Will a double-replacement equation occur? What are the general characteristics that help you recognize double-replacement reactions?

Assuming that each single-replacement reaction occurs, predict the products and write each balanced chemical equation. Use the periodic table or the activity series to predict if each single-replacement reaction will occur and, if so, write a balanced chemical equation. Assuming that each double-replacement reaction occurs, predict the products and write each balanced chemical equation.

Use the solubility rules to predict if each double-replacement reaction will occur and, if so, write a balanced chemical equation. Privacy Policy. Skip to main content.

Chapter 4. Chemical Reactions and Equations. Search for:. Types of Chemical Reactions: Single- and Double-Displacement Reactions Learning Objectives Recognize chemical reactions as single-replacement reactions and double-replacement reactions. Use the periodic table, an activity series, or solubility rules to predict whether single-replacement reactions or double-replacement reactions will occur.

Figure 4. Example 2 Will a single-replacement reaction occur?