Chemical Changes
What is a chemical change?
when a new substance is produced
What must you add for evaporation to occur?
heat
Name the three states of matter and give one example of each.
liquid - water
solid - ice, chair
gas - oxygen, carbon dioxide
Name the process that changes a gas into a liquid.
condensation
Show the circle of physical changes using the water cycle.
Explain 2 different chemical changes by giving a real-life example.
- rain (liquid) - freezing (ice) - melting (liquid) - evaopration (gas) - condensation (dew/fog)
- burning wood in a fire, cooking muffins, various
Explain why burning is a chemical change.
it cannot be reversed
What do you need to do to make a physical change happen?
add or take away heat
Do both liquids and gases take the shape of the container they are in? Explain.
Name the process that changes a solid into a liquid.
melting
Name and explain one chemical change experiment we did in class and the chemical change that happened.
various
- jell-o
- dish soap
- etc.
Explain why Jello-o is NOT a physical change.
a new form is created that cannot be reversed (cannot become powder again)
What is matter?
What is a physical change?
change of state - solid - liquid - gas
Why might chemical changes be dangerous?
they can explode
produce heat
produce fire
Explain how fog builds on a bathroom mirror or a car window.
**Double Jeopardy**
condensation
**Double Jeopardy - What is another way can we see this?**
When the molecules are spread out a little bit and move slowly, what state are they in?
liquid
How might recycling be both a positive and a negative change?
Positive: really good for the environment, reusing materials instead of making more
Negative: costs money to create recycling plants/hire staff to recycle/not everyone participates/not everything is recyclable
What are 3 ways that you know a chemical reaction has occurred?
**Double Jeopardy**
1. bubbles - produces gas 2. new substance is formed 3. new colour is created 4. heat is produced 5. cannot be reversed
** Double Jeopardy - What are 3 chemical changes that you could see happen outside of school (not experiments)**
Name the 4 physical changes.
freezing, melting, evaporation, condensation
Describe the arrangement of the molecules and how they move in all 3 states of matter.
liquid - somewhat spread out, move freely
gas - spread out, move quickly
solid - close together, vibrate a little
Name 3 ways we impact the environment. They can be positive and/or negative.
- recycling
- littering
- picking up garbage
- various