Chemistry 101 Flashcards
What is a chemical reaction?
A change which involves the formation of a new substance
What is effervescence?
When a gas is produced in a chemical reaction
What is precipitation?
When a solid is formed in a chemical reaction
What is a precipitate?
The solid formed in precipitation
What does combustion mean?
Explosion
What is an exothermic reaction?
A chemical reaction which gives out heat
What is an endothermic reaction?
A chemical reaction which takes in heat
What are reactants?
The substances we start with in a chemical reaction
What are products?
The new substances formed in a chemical reaction
What is photosynthesis?
The process of a plant making food
Which reaction is reversible?
Physical reaction
Which reaction isn’t reversible?
Chemical reaction
What is a physical change?
A change with no new substances formed in it
Is mixing substances considered as a physical change?
Yes, as long as no new substances are formed
The components of air:
Oxygen, nitrogen, argon, and carbon dioxide
The components of sea water:
Water, salt, and other dissolved substances
The components of soil:
Rock fragments, water, dissolved minerals, air, and humus
The components of a rock:
Different minerals
What is humus?
A type of fertilizer
Name the states of matter:
Solid, liquid, and gas
Name the common changes of state:
Melting, boiling, condensation, freezing, evaporation, and sublimation
Melting:
Solid to liquid
Boiling:
Liquid to gas
Evaporation:
Liquid to gas
Condensation:
Gas to liquid
Freezing:
Liquid to solid
Sublimation:
Gas to solid or solid to gas
How can you change a state?
By heating or cooling
What is matter?
The scientific word used to describe all the different types of substances and materials found in our universe
What is the boiling point?
The temperature at which a liquid rapidly turns into a gas
What is the melting point?
The temperature at which a solid turns into a liquid
What is the freezing point?
The temperature at which a liquid turns into a solid
Explain the particle theory?
All matter is made up of tiny particles which are in constant motion. There are beliefs that there are forces of attraction holding the particles together
What is an atom?
The simplest particle
What is the diameter of the largest atom?
0.000 000 000 5 m
What is a molecule?
A group of two or more atoms which are joined together
How do you name the differences between the states of matter?
Their movements, spacing, and forces of attraction between them
Describe the atoms/molecules in a solid:
Strong forces of attraction, held closely together, and wobble back and forth
Describe the atoms/molecules in a liquid:
Weaker forces of attraction, slightly further apart, and move around each other
Describe the atoms/particles of a gas:
Weak forces of attraction, particles are very far apart, and can move in about all directions
What is diffusion?
When the particles of one substance spread out and mix with the particles of another substance
Where does diffusion occur the fastest?
In gases because the particles in gases move the fastest
What happens when a substance expands?
It gets bigger
What happens when a substance contracts?
It gets smaller
What is density?
The mass of a unit volume of a material substance
What is mass?
A large body of matter with do definite shape
What is volume?
The amount of space a substance or object occupies
How do you calculate density?
Mass/volume
How do you calculate volume?
length * width * height
What is volume measured in?
cubic centimeters (cm3)
What is mass measured in?
Grams (g) and kilograms (kg)
What is air pressure?
The force of air particles hitting a surface
What is a vacuum pump used for?
To remove the air from inside a container
What can we use to measure air pressure?
Barometer
What is the unit of air pressure?
Pascals (Pa)
Why are gases less dense than liquids and solids?
Because the particles of a gas are further apart
