Dissolving and Mass: Does It Change?

Dissolving and Mass: Does It Change?

Year 7 Science Investigation Exploring conservation of mass in chemical reactions Hands-on experiment with Alka-Seltzer

WALT (We Are Learning To)

Safely carry out a scientific experiment Accurately measure and record mass using a balance Describe what happens when Alka-Seltzer reacts with water Explain why mass stays the same in a closed system

Success Criteria - How We'll Know We've Succeeded

Follow all safety procedures during the experiment Use the balance correctly and record accurate measurements Observe and describe the fizzing, bubbling, and gas production Use scientific reasoning to explain our results

What Do You Think Will Happen?

When we put Alka-Seltzer in water, what will we observe? Do you think the total mass will increase, decrease, or stay the same? Why do you think this will happen?

What is Alka-Seltzer?

Contains sodium bicarbonate (baking soda) Contains citric acid When mixed with water, these chemicals react The reaction produces carbon dioxide gas This is why we see fizzing and bubbling

Safety First - Our Laboratory Rules

Wear safety goggles at all times Handle tablets carefully - don't eat them Keep water away from electrical equipment Work in pairs and help each other Report any spills immediately Follow teacher instructions step by step

Step-by-Step Method

Time to Experiment!

Collect your equipment: bag, water, tablet, balance Work with your partner to follow each step Record your measurements carefully Observe what happens during the reaction Take photos or draw what you see

Recording Our Results

{"left":"Mass before reaction (bag + water + tablet)\nMass after reaction (bag + water + products)\nWhat we observed during the reaction","right":"Any changes in the bag's appearance\nTemperature changes we felt\nHow long the reaction took"}

What Did We Discover?

The mass stayed the same before and after the reaction Even though gas was produced, no mass was lost This demonstrates the Law of Conservation of Mass In a closed system, mass cannot be created or destroyed The atoms just rearranged into different molecules