BackChemistry - Acids and Bases
Terms in this set (49)
What is an atom?
An atom is the smallest particle of an element that still has that element’s properties.
What are the three main subatomic particles in an atom?
The three main subatomic particles are protons, neutrons, and electrons.
How are protons, neutrons, and electrons different?
Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.
Where are protons, neutrons and electrons found in an atom?
Protons and neutrons are found in the nucleus at the center of the atom. Whereas, electrons move around the nucleus in energy levels or shells.
What does atomic number tell you?
The atomic number tells you the number of protons in an atom.
What does mass number tell you?
Mass number is the total number of protons and neutrons in the nucleus.
How do you calculate the number of neutrons?
Neutrons = mass number − atomic number.
What defines an element?
An element is a substance made of atoms that all have the same number of protons.
How are elements represented in chemistry?
Elements are represented by symbols, usually one or two letters, such as H for hydrogen or O for oxygen. The first letter of the symbol is always capitalised but if there is a second letter, it is always in lowercase.
What is the structure of the periodic table based on?
The periodic table goes in order of increasing atomic number. Elements with similar properties are in the same column (group). Example: Group 1 elements (like sodium) all react in similar ways because they each have 1 valence electron.
How can you determine the group of an element from its electron arrangement?
The number of electrons in the outer shell corresponds to the group number of the element in the periodic table.
What is electron configuration?
Electron configuration shows how electrons are arranged in shells around the nucleus.
What is a valence electron?
A valence electron is an electron in the outermost shell of an atom.
Why are valence electrons important?
Valence electrons determine how an atom reacts and what ions it forms.
What happens to reactivity as you go down Group 1?
Reactivity increases because the outer electron is further from the nucleus and easier to remove.
What happens to reactivity as you go down Group 17?
Reactivity decreases because atoms get larger and attract electrons less strongly.
What role do electrons play in chemical reactions?
Electrons, especially those in the outer shell, are involved in forming chemical bonds during reactions.
How are positive and negative ions formed?
Atoms gain or lose electrons to form ions: losing electrons forms positive ions, gaining electrons forms negative ions.
How do you write the formula for common ions?
Use the element symbol with the ion charge as a superscript, e.g., Na + for sodium ion.
What is a cation?
A cation is a positively charged ion formed when an atom loses electrons.
What is an anion?
An anion is a negatively charged ion formed when an atom gains electrons.
What is a polyatomic ion?
A polyatomic ion is a charged group of atoms bonded together, like SO₄²⁻
What is ionic bonding?
Ionic bonding is the electrostatic attraction between positively and negatively charged ions.
How do you determine the number of atoms in a compound from its chemical formula?
Count the subscript numbers after each element symbol to find the number of atoms of each element.
What is a chemical formula?
A chemical formula shows the types and numbers of atoms in a compound.
What is a word equation in chemistry?
A word equation shows the names of reactants and products in a chemical reaction.
What is a balanced symbol equation?
A balanced symbol equation uses chemical symbols and formulas with equal numbers of atoms on both sides.
How do you write word and symbol equations for acid-base reactions?
Write reactants and products using names for word equations and chemical formulas for symbol equations, ensuring balance.
What does the Law of Conservation of Mass state?
Mass cannot be created or destroyed, so atoms must balance in equations.
What is the particle theory in chemical reactions?
The particle theory explains that matter is made of particles that collide to react.
What is collision theory?
Collision theory states that particles must collide with enough energy and proper orientation to react.
How is reaction rate defined?
Reaction rate is the speed at which reactants change into products.
What factors affect reaction rates?
Temperature, concentration, surface area, and catalysts affect how fast reactions occur.
What is a catalyst?
A catalyst speeds up a reaction without being used up.
How does temperature affect reaction rate?
Higher temperature increases particle energy, causing more successful collisions.
How does concentration affect reaction rate?
Higher concentration means more particles, leading to more collisions.
How does surface area affect reaction rate?
More surface area allows more particles to collide, increasing reaction rate.
What is an acid?
An acid is a substance that donates hydrogen ions (H+ ) in solution.
What is a base and an alkali?
A base accepts hydrogen ions; an alkali is a base that dissolves in water to release OH
How can indicators classify substances as acid, alkali, or neutral?
Indicators change color depending on pH, showing if a substance is acidic, alkaline, or neutral.
What is the pH scale used for?
The pH scale measures acidity or alkalinity, ranging from 0 (acidic) to 14 (alkaline), with 7 neutral.
What are neutralisation reactions?
Neutralisation is a reaction where an acid and a base react to form water and a salt.
What are the products of neutralisation reactions?
The products are water and a salt.
What is an indicator?
An indicator is a substance that changes color depending on pH.
What is a metal oxide?
A metal oxide is a compound of a metal and oxygen, often basic.
What is a metal hydroxide?
A metal hydroxide is a compound containing metal ions and OH⁻ ions.
What is a metal carbonate?
A metal carbonate contains metal ions and CO₃²⁻ ions.
What gas is produced when acids react with carbonates?
Carbon dioxide (CO₂) is produced.
What are some everyday uses of acids, alkalis, and neutralisation?
They are used in cleaning, digestion, agriculture, and manufacturing processes.