Chemical Changes Virtual Lab

Name: Anayeli Malave Date: 10/29/2025 Chemical Changes Virtual Lab Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: acid, base, catalyst, chemical change, coefficient, conservation of matter, decomposition, dissolve, double replacement, endothermic, exothermic, indicator, ion, physical change, product, reactant, single replacement, subscript, synthesis Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1.​ A student mixes baking soda and vinegar in a glass. The results are shown at left. Do you think any new substances are being created in this mixture? If so, how do you know? I think Carbon Dioxide is the material that emerged from the mixture, when vinegar and baking soda mix carbon dioxide is produced. ​ ​ ​ ​ ​ ​ ​ ​ 2.​ Suppose this was done on top of a balance. Do you think the mass would change as the reaction proceeded? If the gas is allowed to escape the mass will decrease and not stay the same ​ ​ ​ 3.​ What do you think would happen to the mass if the reaction took place inside a sealed plastic bag? ​ it wouldn’t change because of the seal ​ ​ ​ ​ ​ ​ Gizmo Warm-up A chemical change, (or chemical reaction) occurs when one or more substances, called reactants, are transformed into different substances, or products. In the Chemical Changes Gizmo, you will look for evidence of chemical changes by looking at changes you can see, touch, or smell. To begin, check that Reactant 1 is Sodium and Reactant 2 is Water. Sodium is a metal so soft you can cut it with a knife. 1.​ Click Play ( ). What do you observe? the sodium of glass was removed and it poured water and the sodium scattered in the water which made the mass higher ​ ​ ​ ​ ​ ​ ​ ​ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved 2.​ Do you think a chemical reaction has taken place? Explain. ​ ​ ​ ​ ​ yes i do think that because the gas released into the air it caused a chemical reaction. Get the Gizmo ready: Activity A: Observing chemical changes ●​ Click Reset ( ). Check that the reactants are still Sodium and Water. ●​ Turn on the Label reactants checkbox. Introduction: It is important to distinguish chemical changes, in which new substances are formed, from physical changes, which do not create new substances. In this activity, you will look at many kinds of evidence that chemists use to see if a chemical change has taken place. Question: What kinds of evidence indicate a chemical change has taken place? 1.​ Observe: Some chemical reactions release heat, and others absorb heat. In an exothermic reaction, heat is released and the temperature of the system rises. In an endothermic reaction, heat is absorbed and the temperature of the system decreases. In the Gizmo, drag the Thermometer into the flask of water. A. What is the starting temperature? ​ 21 celsius B. Click Play, and wait for the reaction to end. What is the final temperature? 59 celsius C. Was this reaction exothermic or endothermic? ​ exothermic 2.​ Observe: Two families of chemicals are acids and bases. Acids and bases can be detected by an indicator, which is a substance that changes color in the presence of an acid or a base. Phenol red is an indicator that is yellow in an acid, orange in a neutral solution, and pink in a base. A.​ Click Reset. Drag the Phenol red next to the flask of water. What does the indicator show?​ Start PH: neutral, 423.0g mass, orange phenol B.​ Click Play, and wait for the reaction to end. What does the indicator show now? PH: Basic, 422.9g mass, sodium dissolved, when water was added from the sodium phenol turned red or pink 3.​ Observe: Click Reset. Select the Gas collection setup. Chemists use this apparatus to collect any gases produced in the reaction. From the reaction flask, gases travel through a long tube and into a cylinder of water. As gases bubble into the cylinder, the water is displaced (removed) until the cylinder is filled with gas. ​ ​ Click Play and observe the cylinder. Was any gas produced in the reaction? ​ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved ​​ How do you know? ​ 4.​ Analyze: 1. One way to test what kind of gas is in the cylinder is to use a splint test. A glowing splint is a wooden stick that has been lit on fire and then blown out, resulting in a glowing, red-hot tip. A burning splint is a splint that has a burning tip. The table shows how a splint reacts to some common gases: Gas Carbon dioxide (CO2) or ammonia (NH3) Oxygen (O2) Hydrogen (H2) Glowing splint Goes out Ignites (burns) Does not ignite Burning splint Goes out Continues to burn Small explosion and “pop” sound A.​ Drag the glowing splint next to the cylinder, and observe. What do you see? ​ ​ B.​ Click Reset and click Play, and then bring the burning splint to the cylinder. What happens now? C.​ Based on the table above, what gas do you think was produced in this reaction? 5.​ Interpret: Turn on Show chemical equation. A chemical equation is a shorthand way to describe a chemical reaction. Symbols represent the elements: H for hydrogen, O for oxygen, and Na for sodium. The reactants are to the left of the arrow, and the products are to the right. For example, the equation H2 + O2 → H2O shows that the reactants hydrogen and oxygen combine to form the product H2O, or water. A.​ Look at the reaction shown in the Gizmo. What are the reactants in this reaction? ​ ​ ​ B.​ What are the products in this reaction? ​ ​ ​ ​ ​ ​ ​ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved ​​ ​ These symbols represent sodium hydroxide and hydrogen gas. Sodium hydroxide is a strong base. (Chemicals that contain the hydroxide ion (OH–) are bases.) C.​ How do the products of the reaction relate to the phenol red test and the splint test? Activity B: Get the Gizmo ready: Conservation of matter ●​ Click Reset. Select Hydrogen peroxide for Reactant 1 and Potassium iodide for Reactant 2. Goal: How does the mass change (or not change) during a chemical reaction? 1.​ Review: In this reaction, hydrogen peroxide is added to a potassium iodide solution. Click Play and observe the reaction. A.​ What do you observe? ​ B.​ What evidence do you see that a chemical reaction is taking place? ​ ​ ​ C.​ Replay the reaction and use the available tools (Thermometer, Phenol red, Glowing splint, Burning splint.) What do these tools indicate? (Note: You will need to switch to the Gas collection setup to use the splint.) Thermometer: Phenol red: Glowing splint: Burning splint: 2.​ Record: Click Reset, and change back to the Normal setup. Notice the mass shown on the electronic balance. A. What is the starting mass for this reaction? B. Click Play. What is the mass when the reaction has finished? C. How does the mass change in this reaction? ​ 3.​ Record: Click Reset, and select the Gas collection setup. Notice that this setup is heavier than the normal setup, but the amount of reactants is the same. A. What is the starting mass for this reaction? Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved ​​ B. How do you think the mass will change during the reaction? ​ ​ C. Click Play. What is the mass when the reaction has finished? ​ ​ 4.​ Explain: Why do you think that mass was lost when the reaction was done in the normal setup, but stayed the same when the reaction was done in the gas collection setup? ​ ​ A fundamental law of chemistry is conservation of matter. This law states that, in a chemical reaction, matter can neither be created nor destroyed. That means that, as long as nothing escapes from the system, the total mass measured at the start of the reaction will be the same as the total mass at the end of the reaction. ​ 5.​ Compare: Turn on Show chemical equation. The small numbers, called subscripts, show how many of each atom there are in the molecule. For example, the molecule H2O contains two hydrogen atoms and one oxygen atom. (Notice that, in this reaction, the potassium iodide (KI) acts as a catalyst. A catalyst is a substance that helps a reaction happen but does not change during the reaction.) Count the total number of hydrogen and oxygen atoms on the left and right sides of the equation: Left side: H O Right side: H O What do you notice? ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6.​ Turn on Show balanced equation. A balanced equation shows how many molecules of each substance take part in the reaction. The coefficients are the big numbers that tell you how many molecules there are. For example, “2H2O” means there are two water molecules and a total of four hydrogen and two oxygen atoms. Carefully count the total number of hydrogen and oxygen atoms on the left and right sides of the balanced equation: Left side: H O Right side: H O A.​ What do you notice? B.​ How does the balanced equation relate to the law of conservation of matter? ​ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved ​​ 7.​ Answer the 5 Assessment Questions under the simulation and take a screenshot of your score (paste below). Note: Only your 1st assessment attempt counts...so make it a good one!! Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved