Atoms & Elements
An element is a substance made up of only one kind of ______?
Atom
How do the properties of a compound compare with the properties of the elements that make it?
They are usually different
What happens to the molecules in water as heat energy is added?
They speed up and move further apart
What is the difference between a physical and chemical change?
Physical changes change the appearance and can usually be undone. Chemical Changes change the chemical composition and cannot usually be undone.
What does the Law of Conservation tell us?
Matter cannot be created or destroyed--the reactants must always equal the products.
How do we find the number of neutrons in an element?
Mass - Atomic # = Neutrons
How many atoms are in the compound represented by the formula C12H22O11?
45 total atoms
True or False: Li and K are similar because they are found in the same group
True
Which of the following involves a chemical reaction: condensation, combustion, dissolving, evaporation?
Combustion
What are the reactants in the equation below?
2Na + O2 → 2NaO
2Na + O2
What elements are in the following chemical equation?
6CO2 + 6H2O --> 6O2 + C6H12O6
Carbon, Hydrogen & Oxygen
What is the difference between mixtures and compounds?
Compounds combine chemically, mixtures combine physically
How can we determine the physical and chemical properties of elements?
By their group
True or False: Water boiling is an example of a chemical change because bubbles are formed
False--It is a physical change because we are just changing states of matter (liquid to gas)
A student mixed 5 g of baking soda with 10 g of vinegar. After the reaction the total mass was 13g. What is the reason for a change in mass?
Open system- A gas was created
Which element has 20 neutrons?
Potassium (K)
What is the difference between and homogenous and heterogenous mixture?
Homogenous mixtures look the same or uniform throughout. Heterogenous mixtures are non-uniform and you can see the different ingredients.
The least reactive elements belong to which group?
Group 18 (Noble Gases)
Which type of chemical reaction releases energy in the form of heat or light?
Exothermic
Does this equation follow the Law of Conservation?
C4 + O2 --> CO2 + H20
No, you cannot create or destroy atoms
What information can be found using element boxes?
Atomic #, Symbol, Atomic Mass, Element Name
Protons, Neutrons & Electrons
How many atoms of Hydrogen are found on the products?
Na + H2O --> NaOH + H2
3
Which group of elements will Sodium (Na) most likely react with?
Group 17 - Noble Gases
What is a preciptate?
A solid that forms from two liquids after a chemical reaction.
If 100 molecules of methane were oxidized in the presence of an unlimited supply of oxygen, how many molecules of carbon dioxide would be produced?
100