Properties
A property is something:
You can see (observe) or measure
State one sign a chemical reaction is happening
Light, temperature change, smell, sound, gas produced
Physical changes changes the atoms or molecules of a substance (T/F)
False
A metal block sinks in water. This means the block is (more/less) dense than the water
More
What is an atom?
A particle
A chemical properties include flammability and heat (T/F)
True
Energy is needed in a reaction to:
Break bonds and make bonds in the reactants and products
Chemical reactions create new substances (T/F)
True
What is mass?
The amount of matter in an object
We practice balancing equations show that:
the mass doesn't change in a chemical reaction
Name 3 properties of metals
Shiny, conduct heat, conduct electricity, malleable, strong
What is needed to start a reaction?
Energy
To cause a chemical change in piece of paper you could:
Burn it
How do you calculate density
Mass / volume
What is the word equation for the reaction between when nitric acid and magnesium oxide react to form magnesium nitrate and water?
nitric acid + magnesium oxide --> magnesium nitrate + water
If you mix two chemicals together you can expect the original properties of the reactants to:
Change
A liquid is at 20 degrees. Another chemical is added and the temperature changes to 38 degrees. This must be a :
Exothermic reaction
Give one example of a chemical change and one example of a physical change
For example: crumpling/tearing/folding paper
burning, cooking etc.
If mass stays constant (the same) and volume increases the density of an object will:
Decrease
What is the missing number _H2+O2-->2H2O
2
Why is it important to know the properties of substances like metals and non metals
Safety, they can be used to tell what a substance is
The reactants have LESS energy than the products. This is an:
Endothermic reaction
How are chemical reactions and physical changed different?
Chemical - cannot be reversed, create new substances, change properties
Physical - do not create new substances, do not change atoms, properties stay the same
What is density?
The amount of mass/matter/particles per area/volume
What is the law of conservation of mass?
Atoms/matter cannot be destroyed. Atoms are just rearranged.