Question

1. michael decides to bake bread one morning. he measures ingredients, mixes them other to make a dough, and cooks the dough in an oven. as the dough cooks, michael observes the bread rising. which of the following is evidence of the chemical change in michaels break - making process?

a. sugar dissolving in the liquid batter.
b. the bread rising as carbon dioxide is released.
c. water in the dough being released as water vapor.
d. the dry ingredients mixing with the wet ingredients.

1. substances change states when they move between solid, liquid, and gas forms. when a substance changes from one state of matter to another, it has undergone

a. a reduction in mass.
b. an increase in mass.
c. a chemical change.
d. a physical change.

1. anthonys homework assignment is to demonstrate that an orange has already undergone a chemical change. which of the following should he bring to class to best demonstrate a chemical change?

a. diced orange
b. rotten orange
c. peeled orange
d. mashed orange

1. substances change state when they move between solid, liquid, and gaseous forms. what happens to a substance when it changes form one state to another?

a. a reduction in mass
b. an increase in mass
c. a chemical change
d. a physical change

1. on a camping trip, rachel and samuel make smores. they break graham crackers in half, place chocolate bars on the crackers, and roast marshmallows over the fire. when they place the hot marshmallows onto the chocolate, the chocolate melts. which of the following actions most directly represents a chemical change?

a. assembling the different ingredients to make the smore
b. breaking the graham crackers into two pieces
c. roasting the marshmallows
d. melting the chocolate

1. after a particularly rainy spring, karen and amanda could no longer bear to stay indoors and, with the first sign of fair weather, ventured outside for a walk through the park. as they passed the jungle gym, they noticed that the iron monkey bars looked different. what can you do to pure, solid iron to chemically change it?

a. cut it
b. melt it

Explanation:

1. Chemical changes result in new substances. Sugar dissolving, water evaporation, and ingredient - mixing are physical changes. Bread rising due to carbon - dioxide release is a chemical change as new gas is formed.
2. Changing states of matter (solid - liquid - gas) is a physical change as no new substances are formed and mass is conserved.
3. A rotten orange has undergone a chemical change due to decomposition, forming new substances. Diced, peeled, and mashed oranges are physical changes.
4. Changing states of matter is a physical change. There is no change in mass and no new substances are formed.
5. Roasting marshmallows involves a chemical change as heat causes chemical reactions in the marshmallows, forming new substances. Assembling, breaking, and melting are physical changes.
6. Cutting and melting iron are physical changes. To chemically change iron, it can be made to react with other substances like oxygen (rusting). But among the given options, none cause a chemical change.

Answer:

1. b. The bread rising as carbon dioxide is released.
2. d. A physical change.
3. b. Rotten orange
4. d. A physical change.
5. c. Roasting the marshmallows
6. None of the above options cause a chemical change to pure, solid iron.