Science Exam Chapter 3: Reaction types

Question 1

Combustion and Corrosion Reactions

Answer 1

*Combustion: Burning process.
- Complete: Fuel + Oxygen → CO₂ + H₂O
- Incomplete: Fuel + Oxygen → CO + H₂O (or C + H₂O)

*Corrosion: Deterioration of materials due to chemical reactions with the environment.

Question 2

Exothermic and Endothermic Reactions

Answer 2

• Exothermic: Releases heat. Example: Burning of methane, Cellular respiration in living organisms

*Endothermic: Absorbs heat. Example: Photosynthesis, Thermal Decomposition

Question 3

Complete vs Incomplete Combustion

Answer 3

*Complete: Clean burn, blue flame, produces CO₂ and H₂O.

*Incomplete: Dirty burn, yellow/orange flame, produces CO, C (soot), and H₂O

Question 4

Neutralization

Answer 4

The reaction between an acid and a base to form water and a salt

Example: HCl+NaOH→NaCl+H2O

Question 5

Carbonate and Metal Reactions

Answer 5

Acid + Carbonate → Salt + Water + Carbon Dioxide.

Example: 2HCl+CaCO3​→CaCl2​+CO2​+H2​O

Question 6

Alpha Decay properties

Answer 6

Symbol: α

Equivalent to: A helium nucleus

Speed: 10% speed of light

Charge: +2

Question 7

Beta Decay properties

Answer 7

Symbol: β

Equivalent to: An Electron

Speed: 90% speed of light

Charge: -1

Question 8

Gamma Decay properties

Answer 8

Symbol: 𝛾

Equivalent to: High energy ray

Speed: 100% speed of light

Charge: 0

Question 9

Half-Life

Answer 9

Time for half of a radioactive substance to decay.

Question 10

Carbon Dating

Answer 10

A method used to determine the age of ancient organic materials by measuring the amount of carbon-14 (14 𝐶) they contain.

Question 11

Alpha Particles

Answer 11

• Ionizing Ability: High (can cause significant damage if ingested or inhaled).
  *Penetration: Low (stopped by paper or skin).

Question 12

Beta Particles

Answer 12

*Ionizing Ability: Moderate (can penetrate skin but not deep tissues).
* Penetration: Medium (stopped by aluminum or plastic).

Question 13

Gamma Rays

Answer 13

*Ionizing Ability: Low (less direct damage compared to alpha particles).
* Penetration: High (requires thick lead or concrete to stop)

Question 14

Isotopes

Answer 14

*Atoms of the same element with different numbers of neutrons.
*Example: Carbon-12 ( 12 𝐶) and Carbon-14 ( 14 𝐶).

Question 15

Radioisotopes

Answer 15

• Unstable isotopes that emit radiation to become stable.
• Example: Carbon-14 ( 14 𝐶), which decays into nitrogen-14 ( 14 𝑁).

Question 16

law of conservation of mass

Answer 16

The Law of Conservation of Mass states that the total mass of reactants in a chemical reaction equals the total mass of the products. (balancing equations)

Question 17

Name the product that indicates an incomplete reaction in a combustion reaction

Answer 17

Carbon Monoxide (CO) and Soot or Carbon (C)

Question 18

Acid + metal

Answer 18

salt + hydrogen gas

Question 18

Acid + base
(Look for acids with H and bases with OH)

Answer 18

salt + water

Question 19

Acid + carbonate
(Look for CO2)

Answer 19

salt + water + carbon dioxide