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Science 9 Hon. extensions
Acids and bases
Firstly - you WILL need the periodic table from here.
Many common pure substances can be classified according to whether they are acids or bases. Some acids and bases are corrosive and poisonous, whereas others add flavour to food or are vitamins.
Acid-base indicators are chemicals that change colour in response to acidic or basic conditions. The pH scale is a number scale for
measuring how acidic or basic a solution is.
A pH value below pH 7 is acidic, pH 7 is neutral, and a pH value above pH 7 is basic.
Generally, the chemical formula for an acid starts with H (hydrogen) on the left of the formula. Bases generally have OH on the right of their chemical formulas.
So, if you add an acid and a base together you will neutralize them and get a water and a salt. That makes sense because it looks like a double replacement reaction. Ex HCl + NaOH -> HOH or simply water (H2O) and NaCl.
Firstly - you WILL need the periodic table from here.
Many common pure substances can be classified according to whether they are acids or bases. Some acids and bases are corrosive and poisonous, whereas others add flavour to food or are vitamins.
Acid-base indicators are chemicals that change colour in response to acidic or basic conditions. The pH scale is a number scale for
measuring how acidic or basic a solution is.
A pH value below pH 7 is acidic, pH 7 is neutral, and a pH value above pH 7 is basic.
Generally, the chemical formula for an acid starts with H (hydrogen) on the left of the formula. Bases generally have OH on the right of their chemical formulas.
So, if you add an acid and a base together you will neutralize them and get a water and a salt. That makes sense because it looks like a double replacement reaction. Ex HCl + NaOH -> HOH or simply water (H2O) and NaCl.
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What are acids and bases?
Many common pure substances can be classified according to whether they are acids or bases. Acids produce hydrogen ions (H+) and bases produce hydroxide ions (OH–) when dissolved in solution. The concentration of hydrogen ions refers to the number of hydrogen ions in a specific volume of solution. Solutions with a high concentration of hydrogen ions are highly acidic. Similarly, solutions with a high concentration of hydroxide ions are highly basic. When an acidic solution is mixed with a basic solution, the solutions can neutralize each other, which means that the acidic and basic properties are in balance.
What is pH?
Testing the pH of a solution is a way of measuring its concentration of hydrogen ions, H+(aq). The pH scale is a number scale that indicates how acidic or basic a solution is. Acids have a pH below 7 and bases have a pH above 7. Neutral solutions have a pH of 7. On the pH scale, one unit of change represents a 10-fold change in the degree of acidity or basicity. For example, a two-unit drop in pH is a 102 or 100 times increase in acidity.
What are pH indicators?
pH indicators are chemicals that change colour depending on the pH of a solution.
Litmus paper can determine whether a solution is acidic or basic. Blue litmus paper turns red in an acidic solution (below pH 7). Red litmus paper changes to blue in a basic solution (above pH 7),
A universal indicator contains a number of indicators that turn different colours depending on the pH of the solution.
Phenolphthalein, bromothymol blue, indigo carmine, methyl orange, and methyl red are other common pH indicators. Each determines pH within a different range.
How are acids and bases named?
Acids: Generally, the chemical formula for an acid starts with an H (hydrogen) on the left-hand side of the formula – that can make them easy to spot.
They are easier to name than you would think.
1 – identify the compound as an acid (starts with the H), then we apply one of three scenarios.
Thats it ... easy right?
Many common pure substances can be classified according to whether they are acids or bases. Acids produce hydrogen ions (H+) and bases produce hydroxide ions (OH–) when dissolved in solution. The concentration of hydrogen ions refers to the number of hydrogen ions in a specific volume of solution. Solutions with a high concentration of hydrogen ions are highly acidic. Similarly, solutions with a high concentration of hydroxide ions are highly basic. When an acidic solution is mixed with a basic solution, the solutions can neutralize each other, which means that the acidic and basic properties are in balance.
What is pH?
Testing the pH of a solution is a way of measuring its concentration of hydrogen ions, H+(aq). The pH scale is a number scale that indicates how acidic or basic a solution is. Acids have a pH below 7 and bases have a pH above 7. Neutral solutions have a pH of 7. On the pH scale, one unit of change represents a 10-fold change in the degree of acidity or basicity. For example, a two-unit drop in pH is a 102 or 100 times increase in acidity.
What are pH indicators?
pH indicators are chemicals that change colour depending on the pH of a solution.
Litmus paper can determine whether a solution is acidic or basic. Blue litmus paper turns red in an acidic solution (below pH 7). Red litmus paper changes to blue in a basic solution (above pH 7),
A universal indicator contains a number of indicators that turn different colours depending on the pH of the solution.
Phenolphthalein, bromothymol blue, indigo carmine, methyl orange, and methyl red are other common pH indicators. Each determines pH within a different range.
How are acids and bases named?
Acids: Generally, the chemical formula for an acid starts with an H (hydrogen) on the left-hand side of the formula – that can make them easy to spot.
They are easier to name than you would think.
1 – identify the compound as an acid (starts with the H), then we apply one of three scenarios.
- If the right side of the compound is an atom say Cl, then rather than ending the compund in ‘ide’ we turn it into ‘ic’ and lead the name with HYDRO Ex. HCL is Hydrochloric acid
- If the right side is a polyatomic ion that ends in ATE we DON’T USE hydro and again turn the end into ‘ic’. Ex. H2CO3 is made of hydrogen and carbonate, so it becomes carbonic acid.
- If it a polyatomic that ends in something else you end it with ‘OUS’. Ex H2SO3 you have hydrogen and sulfite, so it becomes sulphurous acid.
Thats it ... easy right?