UNIT 1 Lessons 4-9 Flashcards
What is the difference between an element and a compound?
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.
Physical change vs chemical change?
Physical change is easily reversible i.e original substance can be recovered. Chemical changes are irreversible i.e. original substance cannot be recovered.
What are the signs of a chemical change?
5 points
- Release of energy as heat & light.
- Change in colour.
- Formation of gas.
- Change in odour.
- Formation of a precipitate. (solids)
What are the types of chemical reactions?
8 points
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
What is the difference between an exothermic reaction and an endothermic reaction?
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.
How to determine in a chemical euqation is its an endo or exothermic reaction?
So exothermic, the energy is on the product side, while endothermic, the energy is on the reactant side.
What is the definition of a combustion reaction?
It is an exothermic reaction that uses oxygen and a fuel.
What are the conditions for combustion to occur?
- Oxydizing Agent
- Ignition temperature
- Fuel (wood, ethanol, gas,coal,food)
True or false
If we do not have an oxydizing agent, a combustion reaction can still occur.
FALSE
What are the types of combustion reaction?
1.Slow combustion (digestion)
2.Rapid combustion (candle burning)
3.Spontaneous combustion (Ms. Kissin in Sicily)
What is the definition of an Isotope?
3 point
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.
What is a “relative abundance”?
The PERCENTAGE of atoms with a specific atomic mass found in a naturally occurring sample of an element.
How do you calculate the relative atomic mass?
mass number(relative abundance) + mass number(relative abundance)/100 = something amu
What are the differences with Isotope notation?
2 points
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.
What is the definition of radioactive decay?
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.
What are the types of radioactive decay?
1.Alpha particles (least dangerous)
2.Beta Particle
3.Gamma radiation (very dangerous)
How to identify if alpha particles were released?
2 points
1.2 protons and 2 neutrons are released.
2.Its movement can be stoped by a sheet of paper.
How to identify if a beta particle was released?
2 points
- A high enerygy electron is released and a neutron turns into a proton.
- Its movement can be stopped by a sheet of foil (aluminium)
True or false
In gamma radiation 2 particles are released due to energy in the form of radiation.
FALSE No particles are released.
What can gamma radiation be stopped by?
High density concrete block.
What is a half life?
The half life of a radioactive element is the time it takes for half the atoms in a sample to decay.
What are the differences between nuclear fusion and nuclear fission?
Nuclear fusion is the process of joining nuclei together, while nuclear fission is the process of splitting a nuclei.
fill in the blank
Nuclear fission adn nuclear fusion both release a lot of …..
ENERGY
How does nuclear energy work?
The energy released by the fission of uranium that heats water.
