UNIT 1 Lessons 4-9

Question 1

What is the difference between an element and a compound?

Answer 1

An element CANNOT be broken down any further and it is located on the periodic table. While a compound CAN be broken down into simple elements. It is a combination of 2 or more different elements.

Question 2

Physical change vs chemical change?

Answer 2

Physical change is easily reversible i.e original substance can be recovered. Chemical changes are irreversible i.e. original substance cannot be recovered.

Question 3

What are the signs of a chemical change?

5 points

Answer 3

1. Release of energy as heat & light.
2. Change in colour.
3. Formation of gas.
4. Change in odour.
5. Formation of a precipitate. (solids)

Question 4

What are the types of chemical reactions?

8 points

Answer 4

1.Synthesis & Decomposition
2.Single displacement & double displacement.
3.Oxidation
4.Combustion
5.Nuclear transformations (fission & fusion)
6.Precipitation
7.Cellular respiration & photosynthesis
8.Acid-Base Neutralization

Question 5

What is the difference between an exothermic reaction and an endothermic reaction?

Answer 5

An exothermic reaction is when heat\energy is released, while an endothermic reaction is when heat/energy is absorbed. So exo is on the product side, while endo is on the reactant side.

Question 6

How to determine in a chemical euqation is its an endo or exothermic reaction?

Answer 6

So exothermic, the energy is on the product side, while endothermic, the energy is on the reactant side.

Question 7

What is the definition of a combustion reaction?

Answer 7

It is an exothermic reaction that uses oxygen and a fuel.

Question 8

What are the conditions for combustion to occur?

Answer 8

1. Oxydizing Agent
2. Ignition temperature
3. Fuel (wood, ethanol, gas,coal,food)

Question 9

True or false

If we do not have an oxydizing agent, a combustion reaction can still occur.

Answer 9

FALSE

Question 10

What are the types of combustion reaction?

Answer 10

1.Slow combustion (digestion)
2.Rapid combustion (candle burning)
3.Spontaneous combustion (Ms. Kissin in Sicily)

Question 11

What is the definition of an Isotope?

3 point

Answer 11

Isotopes have the same number of protons and electrons but their number of neutrons is different. They have the same chemical properties but have different physical properties.

Question 12

What is a “relative abundance”?

Answer 12

The PERCENTAGE of atoms with a specific atomic mass found in a naturally occurring sample of an element.

Question 13

How do you calculate the relative atomic mass?

Answer 13

mass number(relative abundance) + mass number(relative abundance)/100 = something amu

Question 14

What are the differences with Isotope notation?

2 points

Answer 14

1.The numbers are on the left of the chemical symbol instead of being centered.
2.The mass number (# protons + # neutrons) is at the top and the atomic number (# protons) is at the bottom.

Question 15

What is the definition of radioactive decay?

Answer 15

A process of decaying that an unstable atom goes through due to an imbalance in the ration of protons to neutrons to become a more stable atom.

Question 16

What are the types of radioactive decay?

Answer 16

1.Alpha particles (least dangerous)
2.Beta Particle
3.Gamma radiation (very dangerous)

Question 17

How to identify if alpha particles were released?

2 points

Answer 17

1.2 protons and 2 neutrons are released.
2.Its movement can be stoped by a sheet of paper.

Question 18

How to identify if a beta particle was released?

2 points

Answer 18

1. A high enerygy electron is released and a neutron turns into a proton.
2. Its movement can be stopped by a sheet of foil (aluminium)

Question 19

True or false

In gamma radiation 2 particles are released due to energy in the form of radiation.

Answer 19

FALSE No particles are released.

Question 20

What can gamma radiation be stopped by?

Answer 20

High density concrete block.

Question 21

What is a half life?

Answer 21

The half life of a radioactive element is the time it takes for half the atoms in a sample to decay.

Question 22

What are the differences between nuclear fusion and nuclear fission?

Answer 22

Nuclear fusion is the process of joining nuclei together, while nuclear fission is the process of splitting a nuclei.

Question 23

fill in the blank

Nuclear fission adn nuclear fusion both release a lot of …..

Answer 23

ENERGY

Question 24

How does nuclear energy work?

Answer 24

The energy released by the fission of uranium that heats water.

Question 24

How do you get an atom to split in nuclear fission?

Answer 24

The nuclei must be hit by a fast moving neutron.

Question 25

How does nuclear fission create a chain reaction?

Answer 25

When the atom splits, neutrons are released. They go on to hit other nuclei.

Question 26

What are the types of fossil fuels?

Answer 26

1.Coal
2.Oil
3.Natural gas

Question 27

Explain how we generate energy using fossil fuels and nuclear energy.

Answer 27

1. Energy heats water to steam
2. steam turns turbines
3. Turbines turn generator
4. Electrical power!!!!