HMH Unit 2.3 Pgs 136-138

HMH Unit 2.3

Pgs 136-138

Chemical Changes

• THE BEFORE AND THE AFTER ARE DIFFERENT!!!

• During a chemical change, new matter is formed.

• There are many different ways to see a chemical change.

Chemical Changes

• Gases are released

• Color changes

• Temperature change

• Makes light

• Change is volume

• Change in taste or smell

• Makes a precipitate

Chemical Changes

• Burning things are a great example of a chemical change.

• When something burns, energy is released in the form of heat.

• The burning substance changes into something new as heat is released.

• The buring substance changes into something new as heat is realeased.

• Think of the pile of ashes at the end of a fire. You can't turn them back into wood.

Multiple Select

Which of the following are part of physical changes?

• strong odor

• breaking in half

• temperature change

• bending

• precipitate

Multiple Select

Which of the following are part of chemical changes?

• strong odor

• breaking in half

• temperature change

• bending

• precipitate

Epsom Salt and Ammonia

• Chemical changes can be dangerous.

• When you mix epsom salt and ammonia together, they create a chemical change.

• Ammonia is dangerous; the amounts used in labs can irritate your skin, eyes, throat, and lungs.

• This is why the lab needs to be done in a well ventilated area.

Rusting and Rotting

• Have you ever seen a rusty metal car? Rusting is another example of a chemical change.

• If metals are not protected and they get wet, they may start to rust.

• The water causes the metal to develop a reddish-brown color.

• Over time, the spot where the rust forms will "eat away" at the car.

• This will form a hole. The rust will spread, and the entire metal car will fall apart.

Multiple Select

Describe the appearance of the car and the environment it’s in. Select all that apply.

• The car looks new

• The car looks old and rusty

• The landscape looks well kept

• The landscape looks overgrown

Multiple Select

Describe the appearance of the car and the environment it’s in. Select all that apply.

• There is little to no change

• The car has some rust

• The landscape has more weeds and wild plants

• There is little to no change in the landscape

Open Ended

What has happened to the car ? Use complete sentences.