Science Unit Test Practice
what is a physical property of matter?
the characteristics of a matter that can be described or observed without involving any chemical reactions
what is qualitative physical properties?
descriptions of the physical QUALITIES of something
what is quantitative physical properties?
physical properties that are MEASURED and assigned a number of QUANTITY to (mass, volume, density, melting point etc.)
why can solid objects with the same volume have different masses, and why can solid objects with different volumes have the same mass?
it is because of the different DENSITIES.
a block of aluminum occupies a volume of 15.0 mL and its mass is 40.5g. what is its density?
d = 2.7g/mL
A rectangular block of copper metal mass is 1896g. The dimensions of the block are 8.4cm by 4.6cm by 5.5cm. What is the density of copper?
V= 212.5cm³
D = 8.9 g/cm³
What is the mass of ethanol that exactly fills a 200.0 mL container? the density of ethanol is 0.789 g/mL
(multiply volume and density)
M = 157.8g
The mass of the battery is 25g. The initial volume was 21mL but the final volume is 27mL. What is the actual volume? What is the density?
(subtract the initial and final volume)
V = 6mL
D = 4.2 g/mL
If the density of a silver wire is 8.96cm³/g, what is the density of the wire you cut in half, and why?
The density of the wire will still be 8.96cm³/g, because the density of something NEVER changes.
What is chemical properties of matter?
describe the ability of matter to react with another substance to form one or more new substances with different properties. it can only be observed when a substance chemically interacts with another sunbstance.
what is a physical change?
changes that alter a substance WITHOUT changing the chemical identity or composition. examples would be altering the appearance of the object and a change of state of a substance (solid to liquid, liquid to gas)
what is a chemical change?
changes where one type of matter changes to produce one or more different types of matter (aka chemical reactions). the matter that is produced has a DIFFERENT identity and DIFFERENT properties from the original.
what does solid look like in the macroscopic scale?
Solid is just solid. It has its own shape/structure and own volume.
what does solid look like in the microscopic scale?
solid particles are very still because the attraction force is very strong and the kinetic energy is low.
what does liquid look like in the macroscopic scale?
Liquid just takes up any container's shape. It has no definite shape but it has a definite volume.
what does liquid look like in the microscopic scale?
Liquid particles are moving around at the bottom of its container. Thats why liquids take up their container's shape, because the attraction force and kinetic energy are equal.
what does gas look like in the macroscopic scale?
Gas sometimes can not be seen but it takes up all of the space in the room. It has no definite shape and volume
what does gas look like in the microscopic scale?
Gas particles are freely moving around the space given because the kinetic energy is very high and the attraction force is very low.
Why is kinetic energy and temperature thought of as the same thing?
It can be thought of being the same thing because the high kinetic energy of the particles causes collisions and these collisions produce heat.
How does dissolving work using KMT
The solvent has a higher kinetic energy, which means it will transfer some of that energy to the particles of the solute.
As the kinetic energy in the solute particles increase, they will eventually start to move around and collide with each other and push apart.
How does diffusion work using KMT
scenario example: as the odor particles escape the oven (bcus they are in a gas state). Once they move into the air, these particles will collide with the air particles and these collisions will send them soaring into random directions. which explains the more the odor particles the stronger the scent will be
How does thermal expansion work using KMT
the 3 states of matter normally EXPAND when they are heated and CONTRACT when they are cooled.
Thermal expansion happens when it gets heated. When the particles get heated, the kinetic energy increases severely. Which causes the particles to move around and collide at the walls of the container, causing to take up more space and have a greater volume.
How many charges does each subatomic particle have?
Proton: 1 POSITIVE charge
Electron: 1 NEGATIVE charge
Neutron: ZERO CHARGE (lit neutral)
Why don't electrons and protons just stick together?
The speed of the electron's travel around the nucleus prevents the electrons from sticking to the prtons and prevents the electrons from falling into the nucleus.
How many protons does selenium have? How many electrons and why?
Selenium has 34 protons and has 34 electrons. It is the same because ONE positive charge of one proton is equal to ONE negative charge of one electron.
Which subatomic particles are composite particles and are elementary particles?
Protons and neutrons are composite particles.
Electrons are elementary particles.
What is the difference between composite particles and elementary particles?
A proton and a neutron is a composite particle because it is composed of quarks and gluons.
An electron is made up of itself, nothing is more smaller than it. It belongs to the family of LEPTONS.
How many up and down quarks does a proton have?
2 up quarks 1 down quark, and gluon
How many up and down quarks does a neutron have?
2 down quarks, 1 up quark, and gluons.
With Kinetic Molecular Theory, why does state change happen?
State changes happen when energy is added or removed from a system, causing the kinetic energy of the particles to increase or decrease. When the kinetic energy reaches a certain threshold, the balance between particle motion and intermolecular forces shifts, resulting in a change of state.