Science - Acids and Bases Flashcards
What is an acid
compounds that dissolve in water to release hydrogen ions
What are the properties of acids
corrosive, taste sour, pH less than 7
What is a base
alkalis - a substance that can accept hydrogen ions in water and can neutralize an acid
What are the properties of bases
caustic, taste bitter, pH more than 7
What is an alkali
Substances that are chemically the opposite acids. A base that dissolves in water is called an alkali
What are some common acids
Hydrochloric acid (HCl)
Sulfuric acid (H₂SO₄)
Nitric acid (HNO₃)
What are some common bases
Sodium hydroxide (NaOH)
Potassium hydroxide (KOH)
Calcium hydroxide (Ca(OH)₂)
Acids and bases react to ____ each other
Neutralise
What is the pH scale
a system to show whether a substance is acidic, basic (base) or neutral.
What is the range of the pH scale
0-14
0 is most acidic and 14 is most basic
What is the pH of a neutral substance
7
What is the universal indicator
A universal indicator is a natural dye that changes colour in a substance to show if it is a acid, base or neutral
What are the colour changes in a universal indicator
0-1: Dark red (strong acid)
2: Red (strong acid)
3-5: Orange (strong-weak acid)
6: Yellow (weak acid)
7: Green (neutral)
8-9: Light blue (weak base or alkali)
10: Blue (weak base or alkali)
11-12: Indigo (strong base or alkali)
13-14: Purple (strong base or alkali)
What is the colour changes in litmus paper
Red paper will turn blue in a BASIC solution
Blue paper will turn red in a ACIDIC solution
What is the colour changes in phenolphalein
It is colourless in a acidic or neutral solution and pink in a basic solution
Salts are _____ that consist of one ____ and one or more ______ elements eg NaCl
compounds, metal, non-metal
A reaction between an acid and alkali is called ________ as water is produced
neutralisation
Acids give off __ ions, bases give off ___ ions. These combine to give H₂0
H+, OH-
What are three ways to produce salt
Acid + base = (arrow) salt + water
Acid + metal = (arrow) salt + hydrogen
Acid + metal carbonate = (arrow) salt + water + carbon dioxide
What are reactants
The substances you are putting in
What are products
The new substances formed
What are some common carbonates
Sodium carbonate (Na₂Co₃)
Calcium carbonate (CaCo₃)
Sodium hydrogen carbonate (NaHCo₃)
What is the general equation for acid and metal carbonate neutralisation
Acid + metal carbonate = (arrow) salt + water + carbon dioxide
What are reaction rates
describes how fast a chemical reaction occurs.
usually reactions begin rapidly and then slow down as the reactants are used up. eventually the reaction stops when one or both of the reactants have been used up.
What does the collision theory state to occur
There must be a collision between the reacting particles. The particles must collide with sufficient energy to break forces holding particles. The particles must collide in the correct orientation or position.
What is the effect on temperature on reaction rate using collision theory
As the temperature increases, particles gain more kinetic energy which means they will move quicker and more particles will have enough energy for effective collisions to occur. The reaction rate will be faster with higher temperature
What is the effect on surface area on reaction rate
If a larger surface area is exposed, more particles are available for collisions. Therefore a larger surface area means a faster rate of reactions.
