Chemical reactions
🌟 This Topic is About...
- ⚗️ I will learn how substances react together to make new ones in a chemical reaction.
- 🧪 I will find out what reactants and products are in chemical reactions.
- 👀 I will observe and describe evidence that shows a chemical reaction has happened.
- ✏️ I will record my observations in clear drawings.
- 💡 I will write a conclusion after completing an investigation.
- 🌡️ I will learn how to measure temperature accurately.
You’re going to explore the exciting world of chemical changes! 🔥🧪
🌟 Key Words
- chemical reaction
- products
- react
- reactants
- evidence
📖 Tap to Learn the Meanings!
- ⚗️ chemical reaction: When two or more substances mix and make something new. 🔥
- 🧪 react: To mix or join with another substance and cause a change. 🔄
- 🧬 reactants: The starting substances in a chemical reaction. 🌡️
- ✨ products: The new substances made after a reaction happens. 🌈
- 🔍 evidence: The clues or signs that show a reaction has taken place — like color change or heat. 👀
Fantastic! You now know the key words for learning about chemical reactions! 🎉
⚗️ Reactants and Products
When some substances are mixed together, they change and form a new substance. This is called a chemical reaction. We say that the substances react together. The substances that react together are called reactants. The new substances that form are called the products.
🔍 Let’s Investigate!
🤔 Question: Can you identify the reactants and products in a simple chemical reaction?
🧰 You will need: vinegar, bicarbonate of soda, a jar with a wide mouth, a spoon
📝 Method:
- Pour some vinegar into the jar. 🧴
- a) Add a teaspoon of bicarbonate of soda into the jar and observe what happens. 👀
b) Make a drawing of your observations. ✏️ - Try to explain what you observed. 💭
- Which substances were the reactants? ⚗️
- Which substance was the product? 🧪
- a) Wait about five minutes. Can you observe any other product? ⏳
b) Describe what you observe. 🔍
🧠 How am I doing?
- Could I make a drawing of my observations? 🎨
- Could I explain my observations clearly? 💬
- Could I identify the reactants in the chemical reaction? ⚗️
- Could I identify any products formed in the reaction? 🧪
👀 Tap to See a Possible Explanation
- Reactants: Vinegar (acid) and bicarbonate of soda (base). 🧴🧂
- Product: Carbon dioxide gas is released — bubbles form! 💨
- Observation: The mixture fizzes and produces bubbles because a chemical reaction is taking place. ✨
Great job investigating chemical reactions! 🌟
💡 Evidence for Chemical Reactions
Sometimes we can see that a product has formed in a chemical reaction. For example, when vinegar and bicarbonate of soda react, we can see that a gas is produced. The gas is evidence of the reaction. There are also other ways we can tell if a chemical reaction has taken place.
🔍 Think Like a Scientist 2: Investigate Evidence for Chemical Reactions A
🤔 Question: What signs show that a chemical reaction has taken place?
🧰 You will need: water, cornstarch, iodine solution, a dropper, a spoon, limewater, a drinking straw, beakers
🧪 Method:
- a) Pour some water into a beaker. Add three full droppers of iodine solution. 💧
b) Make a drawing of your observations. ✏️
c) Add a spoon of cornstarch to the beaker and stir. 🥄
d) Make another drawing of your observations. 🎨 - a) Pour some limewater into a beaker. ⚗️
b) Breathe air into the limewater using a straw. Which gas is in the air you breathe out? 🌬️
c) Write one or two sentences to describe your observations. ✍️ - How do you know that a chemical reaction has taken place in this investigation? 💭
🛡️ Safety First:
- Take care not to suck up the limewater into your mouth. 🚫🥤
- Limewater can irritate your eyes and skin — handle it carefully. 👀⚠️
🌟 Tap to Reflect
- Could I make clear drawings of my observations? 🎨
- Did I explain what I saw correctly? 💬
- Could I identify the reactants and products in each test? ⚗️
- Did I spot the evidence that a reaction had taken place? 👀
Excellent investigating — you’ve found the clues that prove a chemical reaction happened! 🧪✨
🔍 Investigate Evidence for Chemical Reactions B
🤔 Question: What signs show that a chemical reaction has taken place when using wire wool and vinegar?
🧰 You will need: wire wool, vinegar, a beaker, a thermometer, a timer
📝 Method:
- Loosen up a ball of wire wool and place it in a beaker. Pour vinegar on the wire wool and let the beaker stand for one to two minutes. Make sure all the wire wool is in contact with the vinegar. 🧴
- Place a thermometer into the middle of the wire wool and record the temperature reading. 🌡️
- Wait five minutes, then record the temperature reading again. What do you observe? 👀
- How do you know that a chemical reaction has taken place in this investigation? 💭
- Write a conclusion for the investigation. ✍️
❓ Questions
- Describe three ways that we can tell a chemical reaction has taken place and give an example of each. 💡
- When clear limewater is mixed with carbon dioxide, the reaction forms calcium carbonate. 🧪
a) Name the reactants in the reaction.
b) Name the product in the reaction.
c) How can we tell that the reaction has taken place? - Zara drops a fizzy tablet into a glass of water. What evidence will she have that a chemical reaction is taking place? 💨
🌟 Tap to See Answers
- Signs of a chemical reaction: temperature change, fizzing or bubbling, color change. 🌡️💨🎨
- Reactants: limewater and carbon dioxide. ⚗️
- Product: calcium carbonate (a white solid). 🧂
- Evidence: the solution turns cloudy — proof of a new substance! ☁️
- Zara’s experiment: fizzing bubbles show that gas is being produced, meaning a chemical reaction occurred. 💧💨
Excellent work identifying chemical reaction clues! 🔥🧪👏