Question

1. water freezing into ice shows:

a. mass loss
b. matter conserved
c. a chemical bond change
d. energy formed

1. oil is formed from:

a. sand and metal
b. ancient plants and animals
c. air and water
d. volcanoes

1. recycling aluminum cans is an example of:

a. conservation of matter
b. chemical change
c. growing resources
d. reversing reactions

1. the production of gas bubbles during a reaction indicates:

a. melting
b. heat transfer
c. chemical change
d. a reversible state change

1. renewable resources are used because they:

a. run out fast
b. cause pollution
c. replace themselves naturally
d. generate fossil fuels

1. which is an example of a substance undergoing a chemical change?

a. crushing a can
b. iron rusting
c. mixing sand and salt
d. cutting fabric

1. fossil fuels include:

a. wind and water
b. solar and hydro
c. coal and oil
d. biomass only

1. the total mass after a chemical reaction should be:

a. greater than before
b. zero
c. less than before
d. equal to the mass before

1. which statement describes a physical change?

a. new substance forms
b. mass is destroyed
c. identity stays the same
d. reaction produces gas

Explanation:

• Question 16: Water freezing into ice is a physical change. In physical changes, matter is conserved. Mass is not lost (a is wrong), there is no chemical bond change (c is wrong as it's a physical change), and energy is not formed in the sense of a new energy type creation (d is wrong).
• Question 17: Oil is a fossil fuel formed from ancient plants and animals through geological processes. Sand and metal (a), air and water (c), and volcanoes (d) are not the sources of oil formation.
• Question 18: Recycling aluminum cans is about re - using the same matter. It is an example of conservation of matter. It is not a chemical change (b) as the chemical composition of aluminum remains the same in a general recycling sense (melting and reforming), it's not growing resources (c) as we are just re - using existing aluminum, and it's not reversing reactions (d) in a chemical reaction sense.
• Question 19: The production of gas bubbles during a reaction is a sign of a chemical change. Melting (a) is a physical change (solid - liquid), heat transfer (b) is about energy movement, and a reversible state change (d) like melting/freezing is physical.
• Question 20: Renewable resources are used because they replace themselves naturally. They do not run out fast (a is wrong), many renewable resources like solar, wind cause less pollution compared to non - renewables (b is wrong), and they do not generate fossil fuels (d is wrong).
• Question 21: Iron rusting (\(4Fe + 3O_2+6H_2O = 4Fe(OH)_3\)) is a chemical change as a new substance (\(Fe(OH)_3\)) is formed. Crushing a can (a), mixing sand and salt (c), and cutting fabric (d) are physical changes as the identity of the substances remains the same.
• Question 22: Coal and oil are fossil fuels. Wind and water (a), solar and hydro (b) are renewable resources, and biomass (d) is a renewable resource (though some forms of biomass combustion can have issues, but it's still renewable in terms of growth).
• Question 23: According to the law of conservation of mass, the total mass after a chemical reaction is equal to the mass before.
• Question 24: In a physical change, the identity of the substance stays the same. New substance forms (a) is a chemical change, mass is not destroyed (b) (law of conservation of mass), and reaction produces gas (d) is often a sign of chemical change.

Answer:

1. b. Matter conserved
2. b. Ancient plants and animals
3. a. Conservation of matter
4. c. Chemical change
5. c. Replace themselves naturally
6. b. Iron rusting
7. c. Coal and oil
8. d. Equal to the mass before
9. c. Identity stays the same