⚗️Types of Reactions
What is a chemical reaction?
A process where substances change into new substances.
What does “conservation of mass” mean?
The total mass of substances before and after a reaction is the same.
Name one factor that affects how fast a chemical reaction happens.
Temperature. Huh you think you will get point no
if you are leading -200 if not +300 good students
What is made when an acid reacts with a base?
🟩 Answer: Salt and water.
What do we call substances used at the start of a chemical reaction?
🟩 Answer: Reactants. +500 for saying we are dancers +1 book also
Explain what a displacement reaction is.
When a more reactive element replaces a less reactive one in a compound.
Explain why gas loss can make mass appear to change during a reaction.
If gas escapes, it’s no longer part of the measured mass, making it look like mass was lost.
: Explain how temperature affects the rate of a reaction.
🟩 Answer: It increases particle movement, causing more frequent and energetic collisions.
Explain what happens when an acid reacts with a carbonate.
It makes a salt, water, and carbon dioxide (seen as bubbles).
What are signs a chemical reaction has taken place?
🟩 Answer: Color change, gas released, temperature change, or a new substance appears.
A student burns 2.00g of propane (C₃H₈) in excess oxygen. Calculate the volume of carbon dioxide produced at room temperature and pressure.
Just kidding — it’s a bonus question. No pressure (literally).candy for you
What happens to energy during an exothermic reaction?
Energy is released to the surroundings, usually in the form of heat, causing the surroundings to increase in temperature. sory -100 but ....
Explain why reactions are faster at higher concentrations.
Explain why reactions are faster at higher concentrations.
Why is excess base added during salt preparation?
To make sure all the acid has reacted.
How do you test for hydrogen gas in a lab?
🟩 Answer: Use a lit splint — it makes a squeaky pop sound.
Write the word equation for the reaction between magnesium and hydrochloric acid.
Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen
Explain why a reaction in a sealed container shows no mass change even if gas is produced.
All particles are still inside the container, so the total mass stays the same.
If an acid has a pH of -1, explain how it breaks the standard pH scale and what that means for hydrogen ion concentration.
Bonus round, buddy. You don’t need to break your brain. Relax.
Describe how to make a pure sample of copper sulfate crystals.
🟩 Answer: Add copper oxide to warm sulfuric acid until no more reacts, filter, evaporate, and crystallise.
Write the symbol equation for the reaction between sodium carbonate and hydrochloric acid.
Na2CO3+2HCl→2NaCl+H2O+CO2.
Look at the word equation for the reaction:
calcium carbonate + hydrochloric acid → calcium chloride + carbon dioxide + water
Look at the equipment Chen uses:
(An image showing: dilute hydrochloric acid, conical flask, glass wool plug)
From the second image:
(a) Predict what happens to the mass reading on the balance during the reaction
Explain your answer:
decrease,
The mass reading on the balance will decrease during the reaction.
This is because carbon dioxide gas is produced and escapes from the flask. Even though the total mass of reactants equals the mass of products (Law of Conservation of Mass), the gas is lost to the surroundings, so the balance shows a lower mass.
You carefully mix a measured volume of hydrochloric acid (HCl) with sodium hydroxide (NaOH) in a calorimeter. After the reaction, the solution’s pH is 7, and the temperature rises noticeably.
Q: What type of chemical reaction has occurred? Write the balanced chemical equation for this reaction. Explain why the temperature increases during this process. What are the products formed, and how does this reaction demonstrate the concepts of acid-base neutralization and energy change?
You carefully mix a measured volume of hydrochloric acid (HCl) with sodium hydroxide (NaOH) in a calorimeter. After the reaction, the solution’s pH is 7, and the temperature rises noticeably.
Q: What type of chemical reaction has occurred? Write the balanced chemical equation for this reaction. Explain why the temperature increases during this process. What are the products formed, and how does this reaction demonstrate the concepts of acid-base neutralization and energy change?
Explain, using the particle model, how both temperature and surface area affect reaction rate.
Higher temperature increases particle energy and collisions. More surface area means more places for collisions to happen.
You burn a piece of wood inside a perfectly sealed, airtight container. After the combustion finishes, you measure the total mass of the container, ashes, and all gases inside. The total mass is exactly the same as before you started.
Q: Explain, using atomic and molecular theory, why the total mass remains constant even though the wood appears to have disappeared. How does this observation support the Law of Conservation of Mass? Include a discussion of the states of matter before and after the reaction.
✅ Advanced Answer:
The total mass remains constant because atoms are neither created nor destroyed during a chemical reaction; they are simply rearranged to form new substances. When wood burns, its complex molecules react with oxygen in the air inside the container. This combustion breaks down the wood’s molecules into smaller molecules such as carbon dioxide (CO₂), water vapor (H₂O), and solid ash composed mostly of minerals.
A compound has 74 protons and undergoes alpha decay followed by beta decay twice. What’s the new atomic number?
You thought this was physics class? Bonus question — no points lost for crying.[Actually no points added too]