The teacher can use the chalkboard or dry erase board to teach the general formula for a double replacement reaction. As such, it will not replace hydrogen in a compound with the nitrate ion. However, there is one type of double-replacement reaction that we can predict: the precipitation reaction. If so, identify the products. The law of conservation of mass says that matter cannot be created or destroyed during a chemical reaction.
Not all proposed single-replacement reactions will occur between two given reactants. What are some visible evidences of a chemical reaction? Thus, we predict no reaction in this case. The teacher copy of the lab instructions includes answers to the post lab questions and a student data table with the answers filled in. Sometimes well plates are transparent plastic and sometimes they are opaque and ceramic. Test Yourself Will a single-replacement reaction occur? You cannot swap both; you would end up with the same substances you started with. If you feel any tingling sensations or see any color changes on your skin, flush with water immediately for a minimum of 15 minutes.
For reactions involving metals, use just 1-2 pieces of each metal. They will be given the opportunity to record observations, write formulas for compounds, and balance the chemical equations for a set of double replacement reactions. The teacher will look at the data table to see if students are correctly writing formulas for ionic compounds and balancing equations. If well plates are used and viewed on white paper, students can see the reaction with only three drops of each reagent. The teacher will show students how the positive ion cation of one reactant combines with the negative ion anion of the other reactant. Inform your instructor of any chemical contact as soon as possible. Rubric: There are six reactions.
Since one of the predicted products is insoluble, a precipitation reaction is will occur. To judge whether double-replacement reactions will occur, we need to know what kinds of ionic compounds form precipitates. The students will follow the instructions on the attached lab instruction booklet. For this, we use , which are general statements that predict which ionic compounds dissolve are soluble and which do not are not soluble or insoluble. Allow hands-on learners that may struggle with the conceptual nature of two aqueous solutions forming a precipitate to have multiple note cards with the ions names and symbols to pair up and demonstrate the Double Replacement Reaction. A good estimate is to use two full dropper squirts of each chemical.
The four post lab questions on the back page of the lab booklet should each count ten points. The teacher will want to use the transparent plates. Old substances are converted to new substances, which have unique physical and chemical properties of their own. Students will complete the lab activities 6 double replacement reactions with teacher guidance. The well plates sometimes feel hot.
Up to now, we have presented chemical reactions as a topic, but we have not discussed how the products of a chemical reaction can be predicted. Additionally, the teacher should grade the post lab questions on the last page of the student lab instruction booklet. A list called the does the same thing the periodic table does for halogens: it lists the elements that will replace elements below them in single-replacement reactions. Students who need longer to complete assignments can choose to write the names of the ionic compounds or balance the equations instead of doing both. 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.
In other words, there is a column on the teacher answer key data table with correct observations. Example 3 Use the activity series to predict the products, if any, of each equation. Write the balanced molecular equation identical to what you completed in the previous section , the complete ionic equation and the net ionic equation for these reactions. Compounds of the sulfate ion are generally soluble, but Sr 2+ is an exception: we expect it to be insoluble—a precipitate. Silver and Bromide Ions combined together have a low solubility which allows for it to be a precipitate.
The knowledge will be organized on page three of the student lab instruction booklet referenced in the guided practice section above. A is a chemical reaction in which one element is substituted for another element in a compound, generating a new element and a new compound as products. A typical characteristic of a single-replacement reaction is that there is one element as a reactant and another element as a product. During a chemical reaction both the form and composition of matter are changed. After completing the lab activities, students will balance the equations representing the reactions and write the names of the ionic compounds involved.
During the lab, each participant was given drop bottles, spot plates. The formation of a solid precipitate is the driving force that makes the reaction proceed. The general formula for a double replacement reaction and a description of the reaction is on the first page of the student instruction booklet. These are the chemical formulas and equations for the lab the students are doing today. An Activity Series is provided at the end of the Background section. The teacher answer key referenced in Guided Practice above has a completely filled-out data table describing each reaction including the formulas for the compounds and the chemical equations for the reactions.