Question

B.Give reasons and state the type of change.
1. A student removes a loaf of bread hot from the oven. The student cuts a slice off the loaf and spread butter on it.
2. Your friend decides to toast a piece of bread, but leaves it in the toaster too. The bread is black and the kitchen if full of smoke.
3. You forgot to dry the bread knife when you washed it and reddish brown spots appeared on it.
4. You blow dry your wet hair.
5. In baking biscuits and other quick breads.
6. The baking powder reacts to release carbon dioxide bubbles. The carbon dioxide bubbles cause the dough to me You take out your best silver spoons and notice that they are very dull and have some black spots.
7. A straight piece of wire is coiled to form spring.
8. Food color is dropped into water to give it color.
9. Chewing food to break it down into smaller particles represents a change. but the changing of starch into sugars by enzymes in the digestive system represents _change.
10. In a fireworks show, the fireworks explode giving off heat and light. ​

Answer 1

1. Physical change, because no new substance is formed

2. Chemical change, because the composition of the bread is changed and (cannot be reversed)

3. Chemical change because reaction took place

4. Physical change, because there is no change in the state of the material

5. Chemical changes, beacuse new substances.....

6. Chemical changes, beacuse new things are formed.

7. Physical change, because no new substance is formed, only the structure of the material changed.

8. Depends, If tye color settles, then the change is physical and vice versa.

9. Physical change Chemical change

10. Chemical change, because heat and light is formed