Chemical Changes and Structures Flashcards
What is the pH scale a measure of?
The concentration of hydrogen ions in a substance
What is a neutral solution?
A solution with the same concentration of hydrogen and hydroxide ions
What is the pH of a neutral solution?
7
What is the pH of an acidic solution?
Less than 7
What is the pH of an alkaline solution?
More than 7
Does an alkaline solution have a higher concentration of hydrogen or hydroxide ions?
hydroxide ions
How will the dilution of an acidic solution affect the pH?
It will increase the pH, bringing it closer to 7
How will the dilution of an alkaline solution affect the pH?
It will decrease the pH, bringing it closer to 7
What is dissolved in water to form an acidic solution?
non-metal oxides
What is the word equation for the formation of an acid?
non-metal oxide + water –> acid
What is the word equation for the formation of a metal hydroxide?
metal oxide + water –> metal hydroxide
What is a neutralisation reaction?
A reaction in which a metal oxide reacts with an acid to make water and a salt
What is the word equation for a neutralisation reaction?
metal oxide + acid –> water + salt
What is produced when a metal carbonate reacts with and acid
a salt, water and carbon dioxide
What is the word equation for the reaction between a metal carbonate and an acid?
metal carbonate + acid –> salt + water + carbon dioxide
what is the word equation for the reaction between a metal and an acid?
metal + acid –> salt + hydrogen
How is a salt named?
the first part is named from the the metal in the base that was used
the second part comes from the acid used
What are the factors affecting rate of reaction?
- temperature
- concentration
- particle size/surface area
- use of a catalyst
What is a catalyst?
a substance that speeds up a chemical reaction and remain unchanged by the reaction
How are elements in the periodic table arranged?
In order of increasing atomic number
What are covalent bonds?
a bond formed between two non-metal atoms formed when two positive nuclei are held together by their attraction for a shared pair of electrons
What are the diatomic elements?
Hydrogen, Nitrogen, Florine, Oxygen, Iodine, Chlorine and Bromine
What are the properties of a covalent molecular substance?
- they have strong covalent bonds with molecules and weak attraction between the molecules
- have low melting and boiling points
- do not conduct electricity because their electrons are not free to move
What are the properties of covalent network structures?
- have a network of strong covalent bonds within one giant structure
- have very high melting and boiling points
- do not dissolve
How are ions formed?
when atoms lose or gain electrons to become stable
What are ionic bonds?
the electrostatic attraction between positive and negative ions
Why do ionic compounds have high melting and boiling points?
Because strong ionic bonds must be broken
When do ionic compounds conduct electricity?
when molten or in solution
What is the valency of the noble gases?
0
