Year 8 Chemistry Test Flashcards
What is a catalyst?
A chemical that can speed up chemical change.
How can a reaction rate be increased? (Name at least two things from the list)
- by increasing the amount of reactants that are combined.
- by increasing the concentration of the reactants.
- by increasing the surface area of the reactants.
- by increasing the temperature of the reaction.
- by increasing the pressure that the reaction occurs at.
Which of the 3 types of states (solid liquid gas) is the most compressible and why?
Gas because there is a lot of space between the particles that can be compressed.
Describe all the ways that a physical change can be distinguished from a chemical change…
Physical - change of state, shape & size
Chemical - change in colour
What is the charge of a Neutron?
Neutral.
What is the charge of an electron?
Negative.
What is the charge of a proton?
Positive.
Te atomic number is found by…
The number of protons.
The mass number is found by…
Protons and neutrons.
The area in which the electrons exist is called the…
Neutron cloud.
The area in which the protons and neutrons exist is called the….
Nucleus.
What is the meaning of element?
One type of atom, pure substance.
What is the meaning of atom?
Smallest part of matter.
There are four main factors that effect the rate of reaction. These are…
- concentration
- collisions
- surface area
- temperature
- frequency
- efficient
- activation
- catalyst
- unchanged
- energy
Compare a physical and a chemical change. Is a new product produced?
Yes. A physical reaction would change shape/size but a chemical may change temperature/colour, etc.
Compare a physical and chemical change. Are the reactant atoms changed?
Yes, for chemical.
Compare a physical and chemical change. Can a change of state occur?
Yes, for physical.
Compare a physical and a chemical change. Can a colour change occur?
Yes, for chemical. But also sometimes physical.
If a gas is heated in a balloon, what will occur? What will be observed?
There will be a physical change that will occur because there will be a change in shape (expand/bigger) and also there would be more atoms inside of the balloon.
Explain why mixing is a physical change. Why is it still possible for colour changes to occur?
Because the mixing is not a chemical change. Colour change occurs because the mixing may dilute some of the colour. Eg: cordial in water.
Which of the 3 types of states is the most compressible and why?
Gas, because there is a lot of space between the particles that can be compressed.
Describe a metalloid.
A non-metallic element.
What are the non-metals in the periodic table?
(Total is 19, only told to go up to a certain number) helium, carbon, nitrogen, oxygen, fluorine, neon, phosphorus, Sulfur, chlorine, argon, selenium, bromine, krypton.
What is an important thing to remember about the periodic table?
Periods go across the table.
