Chemistry: Chemical Reactions Test

Difference between mass and matter?

Mass: The amount of matter in an object

Matter: Anything that has mass and takes up space

Different between atoms, elements, and compounds?

Atoms: basic units of matter, similar to a particle of an element

Elements: Substances made of only one type of atom (pure substance)

Compounds: substances made of two or more different types of atoms in a bond (pure substance

What is an intensive physical property?

• Doesn’t depend on the amount of substance present

• ex. Temperature, density, color are intensive because they’re a characteristic of the substance itself

What is an extensive physical property?

• Depends on the amount of substance present

• ex. Mass and volume

Difference between physical properties and physical changes?

Physical properties: describe characteristics of a substance (color, shape, density, etc.)

Physical changes: Alter the form or appearance of the substance without changing its chemical composition (melting ice, breaking a pencil, cutting a piece of paper, etc.)

7 signs of chemical change

1. Change in color

2. Change in smell

3. Change in temperature

4. Production of light

5. Production of sound

6. Production of gas

7. Formation of a precipitate (A solid formed from 2 liquids)

What is a reactant and a product?

Reactants: Substances that undergo a chemical reaction (left side of equation)

Products: Substances formed as a result of the reaction (right side of equation)

What is a pure substance?

A substance composed of only one type of particle with the same chemical and physical properties throughout

What is a mixture?

Combination of two or more substances that are physically combined, but not chemically bonded

what is a homogeneous mixture?

A mixture where its components are uniform throughout, also called a solution (soda, coffee, milk).

What is a heterogeneous mixture?

A mixture where its components are not uniform throughout (pizza, salad, sandwich).

What are the diatomic elements?

• Br - Bromine

• I - Iodine

• N - Nitrogen

• Cl - Chloride

• H - Hydrogen

• O - Oxygen

• F - Flourine

Common symbols used in chemical reactions

.

How to tell if an element is reactive based on location on the periodic table and why?

Elements on left side of periodic table are more reactive (Group 1 - Alkali metals, Group 2 - Alkaline metals)

They are reactive due to their lack of valence electrons, making them prone to lose electrons in a bond, especially when paired with halogens.

What does it mean when an element/compound is oxidized?

Loss of electrons (Increase in oxidization number)

What does it mean when an element/compound is reduced?

Gains electrons (Decrease in oxidization number)

metal + acid
ex. 2Na + 2HCl

single replacement
compound + H₂
2NaCl + H₂

compound + compound
Ca(NO)₃ + 2LiBr

double replacement
compound + compound (switch fronts)
CaBr₂ + 5LiNO₃

nonmetal (F2, Cl2, Br2, I2) + compound
NaCl + 2F₂

single replacement
compound + nonmetal (Br₂, Cl₂, I₂)
NaF + Cl₂

active metal + water
group I & group II
2Na + 2H₂O

single replacement
metal hydroxide + hydrogen gas
2NaOH + H₂

metal compound
FeCl₃ + 3Li

single replacement
metal + compound (weaker metal gets kicked out)
Fe + 3LiCl

hydrocarbon (C&H + Oxygen)
C₃H₈ + 5O₂

combustion
always yields CO₂ + H₂O
3CO2 + 4H20

acid
H₂SO₄

decomposition
always yields nonmetaloxide + H₂O
H₂O + SO₃
*write water first, then balance

metallic chlorate
Zn(ClO)₃

decomposition
always yields metal chloride + O₂
ZnCl₂ + 3O₂
*watch for tm

metallic hydroxide
Pb(OH)₄

decomposition
metal oxide + H₂0
PbO₂ + 2H₂O
*watch for tm

metallic carbonate
BaCO₃

decomposition
metal oxide + CO₂
BaO + CO₂
*watch for tm

binary compound
2FeO

decomposition
element + element
2Fe + O₂
*watch for tm and BrINClHOFS

nonmetaloxide + water

N₂O₅ + H₂O

synthesis acid
2HNO₃

element + element
4Al + 3O₂

synthesis compound
2Al₂O₃

metaloxide + water
MgO + H₂0

synthesis metalhydroxide
Mg(OH)₂

Oxidization number of F?

-1

Oxidization number of H UNLESS paired with a metal?

+1

with metal: -1

Oxidization number of Oxygen UNLESS paired with F?

-2

Paired with F: +2

Oxidization number of elements with no charge?

0