Density + Particle Diagram
What is the formula for density?
D=m/v
What is the law of conservation of mass?
Matter cannot be created or destroyed
What is the difference between a chemical and physical change?
A physical change is generally reversible and no new substance is made.
A chemical change is irreversible and a new substance is created.
What is an atom?
What is a compound?
The fundamental building blocks of all matter
Two or more elements chemically bonded
What is an independent variable?
What is changing in the experiment
In a density column if the object is more dense + less dense than the liquid, what happens?
It will sink
It will float
What is the definition of reactants and what side of the equation is it on?
The reactants is the substances you start with, left hand side of the arrow
Give an example of a physical reaction
melting a popsicle, crumbling a piece of paper, water evaporating while boiling, dissolving sugar in water
During a phase change what happens to the temperature?
It stays the same during the phase change
What is a dependent variable?
What we measure in the experiment
g/cm3
What is the definition of products and what side of the equation is it on?
What is formed during the chemical reaction, right side of the arrow
Give an example of a chemical reaction
burning wood, rust, cooking, digestion, fireworks
What is a mixture?
2 or more pure substances that are physically mixed (ex: atom + compound, etc)
What are the controls in the experiment?
What stays the same in the experiment
Draw the particle diagram for substance after it evaporates.
Teacher will confirm
How can you tell if a reaction is a chemical reaction?
A new substance is created
What types of properties can identify a substance?
Density, Melting Point, Boiling Point (Intensive + Specific)
Give an example of how you can separate a mixture
Any answer that includes: filtration, evaporation, magnet, separating large solids by hand, etc.
What happens to the temperature in an exothermic reaction?
The temperature increases (energy is released)
In a closed system, the mass of the reactants equals the mass of the ______.
Why?
Products
Matter is not able to leave the system
How can you tell that a reaction follows the law of conservation of mass?
The type of atoms + # of atoms in the reactants = The type of atoms + # of atoms in the products
What are 4 pieces of evidence of a chemical change?
1. Color changes
2. Formation of a gas (bubbles)
3. Odor production
4. Temperature changes
What are the 2 different types of mixtures?
Homogenous - evenly spread out in mixture
Heterogeneous - Non-evenly spread out in mixture
What happens to the temperature in an endothermic reaction?
The temperature decreases (energy is absorbed)