Chemistry - Acids & Alkalis

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International hazard symbols indicate dangers with chemicals. So we know what to...

Do to be safe/what precautions to take (correct)

Do in case of spillage or accident (correct)

Avoid using chemicals altogether

Ignore when seeing the symbols

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

This symbol means that the substance is corrosive. The substance attacks and destroys living tissue, such as skin and eyes. You should take precautions such as wearing gloves and eye protection.

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

This symbol means that the substance is toxic. The substance can cause death if swallowed, breathed or absorbed by the skin. You should take precautions such as wearing gloves, googles and having ventilation to keep safe at all times.

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

This symbol means that the substance is flammable. The substance easily egnites and burns quickly. You should take precautions such as not exposing the substance near a naked flame. Signup and view all the answers

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

This symbol means that the substance is harmful to the environment. The substance damages or pollutes the environment. You should take precautions such as not disposing the substance down the sink. Signup and view all the answers

What does this symbol mean, and what is its typical hazard?

Moderate health hazard, causes skin irritation Signup and view all the answers

What does this symbol mean, and what is its typical hazard?

Serious health hazard, causes breathing difficulties Signup and view all the answers

What does this symbol mean, and what is its typical hazard?

Oxidising, makes flammable substances burn more fiercely Signup and view all the answers

Why would a hazard symbol of a 'flame' be on an ethanol bottle?

The symbol of a 'flame' means flammable. This means that ethanol is flammable. Signup and view all the answers

A concentrated solution is a _ amount of dissolved solute in a given volume of water. A dilute solution is a _ amount of dissolved solute in a given volume of water.

greater, small Signup and view all the answers

How could you create a dilute solution from a concentrated solution?

Add more water Signup and view all the answers

How could you create a concentrated solution from a dilute solution? (Select all that apply)

Add more solute Signup and view all the answers

State the definition of a strong acid.

An acid whose molecules break up (dissociate) completely into ions, when dissolved in water. Signup and view all the answers

Select the examples of strong acids:

Hydrochloric acid Signup and view all the answers

The pH values range from _ in strong acids. The pH values range from _ in weak acids.

1-3, 4-6 Signup and view all the answers

What is the definition of a weak acid?

An acid whose molecules so not break up (dissociate) completely into ions, when dissolved in water. Signup and view all the answers

Select the examples of weak acids:

Ethanoic acid Signup and view all the answers

Hydrochloric acid is a solution of acid and has a high _ level. Therefore hydrochloric acid has __ concentrations of hydrogen (H+) ions.

strong, dissociation, high Signup and view all the answers

Ethanoic acid is a solution of acid and has a low _ level. Therefore ethanoic acid has _ concentrations of hydrogen (H+) ions.

weak, dissociation, low Signup and view all the answers

Explain why hydrochloric acid has a lower pH than ethanoic acid.

Hydrochloric acid is a srong acid. Hydrochloric acid dissociates completely in aqueous solutions. Hence, produces a greater concentration of hydrogen ions, therefore having a lower pH. Signup and view all the answers

Explain why carbonic acid has a higher pH than sulfuric acid.

Carbonic acid is a weak acid. Carbonic acid doesn't dissociate in aqueous solutions. Hence, produces a lower concentration of hydrogen ions, therefore having a higher pH. Signup and view all the answers

The higher the number of ____ ions in a certain volume, the _ the hydrogen ion concentration, the more _ the solution is, the lower the of the acidic solution.

hydrogen, higher, acidic, pH Signup and view all the answers

What do pH scales measure?

How acidic/alkaline the solution is Signup and view all the answers

Match the following types of solutions with their corresponding pH levels:

= Neutral solution = pH = 7 Acidic solution = pH less than 7 Alkaline solution = pH greater than 7 Signup and view all the answers

The lower the pH, the more _ the solution is. The higher the pH, the more _ the solution is.

acidic, alkaline Signup and view all the answers

Match the common acids with their correct symbol:

Hydrochloric acid = HCl Sulfuric acid = H₂SO₄ Nitric acid = HNO₃ Ethanoic acid = CH₃COOH Signup and view all the answers

Match the common alkalis with their correct symbol:

= Sodium hydroxide = NaOH Potassium hydroxide = KOH Calcium hydroxide = Ca(OH)₂ Signup and view all the answers

Neutral solutions have an equal number/concentration of and ions.

hydrogen, hydroxide Signup and view all the answers

What is an indicator?

Substances that have different colours in acidic and basic alkaline solutions. Signup and view all the answers

Match the indicator with their colour when in an acidic solution:

Litmus = Red Methyl orange = Red Phenolphthalein = Colourless Universal = Red, orange, yellow, greenish Signup and view all the answers

Match the indicator with their colour when in an alkaline solution:

Litmus = Blue Methyl orange = Yellow Phenolphthalein = Pink Universal = Greenish blue, purple Signup and view all the answers

What is a base?

A substance that reacts with acid to form salt and water Signup and view all the answers

acid + base -> _ + __

salt, water Signup and view all the answers

A reaction between an acid and a base is called a ________ reaction.

neutralisation Signup and view all the answers

Select the substances that can act as a base.

Metal oxides Signup and view all the answers

What is an alkali?

A base that is dissolved in water Signup and view all the answers

Match the following chemical reactions with their products:

Acid + Base -> = Salt + water Acid + Alkali -> = Salt + water Acid + Metal carbonate -> = Salt + water + carbon dioxide Acid + Metal -> = Salt + hydrogen Signup and view all the answers

A salt forms when _____ ions in acid are replaced by _ ions or _____ ions.

hydrogen, metal, ammonium Signup and view all the answers

Match the name of the acid with the type of salt produced:

= Hydrochloric acid (HCl) = Chloride Sulfuric acid (H2SO4) = Sulfate Nitric acid (HNO3) = Nitrate Signup and view all the answers

Describe the process of the carbon dioxide test.

Bubble gas through limewater. Lime water turns milky if carbon dioxide is present. Signup and view all the answers

Describe the process of the hydrogen test.

Place a lighted splint in a hydroxide and air mixsture. Hydrogen gas is present if a squeaky pop is heard. Signup and view all the answers

When aqueous solutions are dissolved in water acid and produces _ ions. This means there is a _ hydrogen ion concentration. This means that the solution is more _ and the pH is ___.

dissociates, hydrogen, higher, acidic, lower Signup and view all the answers

When aqueous solutions are dissolved in water, alkalis produce _____ ions. This means there is a _ hydroxide ion concentration. This means that the solution is more _ and the pH is ___.

hydroxide, higher, alkaline, higher Signup and view all the answers

What are the two ways of making soluble salts?

Acid and an Insoluble base Signup and view all the answers

Match the order of the steps with their description in relation to making insoluble salts:

Step 1 = Mix the two salt solutions in a beaker and stir them to mix Step 2 = Precipitate of insoluble salt will form Step 3 = Place filter paper into a filter funnel and pour the contents of the beaker on to the filter paper Step 4 = Remove the filter paper containing the precipitate and leave it in a warm place Signup and view all the answers

Explain how you could go about making insoluble salts.

Mix the two salt solutions in a beaker and stir them to mix. The precipitate of the insoluble salt will form. Place the filter paper into a filter funnel and pour the contents of the beaker on to the filter paper. Remove the filter paper containing the precipitate and leave it in a warm place. Signup and view all the answers

Match the method of making a soluble salt with when to use which one:

<h1>Method 1 = When one of the reactants is coloured Method 2 = Both reactants are colourless</h1> = Signup and view all the answers

Match the method of making a soluble salt with its equation:

<h1>=</h1> Method 1 = metal oxide + acid -> salt + water Method 2 = alkali + acid -> salt + water Signup and view all the answers

When making a soluble salt (method 1) you should firstly __ the acid in a water bath because a higher temperature will lead to a _ reaction. You should then slowly add the (metal oxide) to the acid and mix until some remains at the _ of the beaker. This will make sure that all the acid has _. Next, you will need to _ to remove the unreacted solid left from the solution. You should then _ the filtrate containing the soluble salt and water into the evaporating dish. Next, heat the solution by gently using a bunsen burner to ____ some of the water. You will have to then leave the solution to to allow the salt to cyrstalise. Filter off the solid salt and then leave it to _.

heat, faster, base, bottom, reacted, filter, transfer, evaporate, cool, dry Signup and view all the answers

Explain how you could go about making soluble salts (method 1).

When making a soluble salt you should firstly heat the acid in a water bath because a higher temperature will lead to a faster reaction. You should then slowly add the base (metal oxide) to the acid and mix until some remains at the bottom of the beaker. This will make sure that all the acid has reacted. Next, you will need to filter to remove the unreacted solid left from the solution. You should then transfer the fittrate containing the soluble salt and water into the evaporating dish. Next, heat the solution by gently using a bunsen burner to evaporate some of the water. You will have to then leave the solution to cool to allow the salt to cyrstalise. Filter off the solid salt and then leave it to dry. Signup and view all the answers

Why, when making a soluble salt, should you first heat the acid in a water bath?

A higher temperature will lead to a faster reaction. Signup and view all the answers

Why should you leave some remaining base (metal oxide) at the bottom of the beaker when adding it slowly?

It makes sure that all the acid has reacted Signup and view all the answers

When making a soluble salt (method 2) you should start with measuring the set volume of _ into a conical flask using a . Then you should add 3-4 drops of an (e.g. phenolphthalein). Then, slowly add the acid to the alkali using a , until the indicator changes - this is called the _ . You should note the exact number of that was needed for the indicator to change colour and react with the alkali. Next, carry out the reaction in a beaker, using the volume of alkali and acid, but without the so that the salt formed isn't _____ with it. You should then _ the solution containing the salt and water into an evaporating dish. Next, heat the solution by gently using a Bunsen burner to ____ some of the water. You will have to then leave the solution to to allow the salt to crystallise. Filter off the solid salt and then leave it to _.

alkali, pipette, indicator, burette, colour, end point, acid, same, indicator, contaminated, transfer, evaporate, cool, dry Signup and view all the answers

Explain how you could go about making soluble salts (method 2).

Start with measuring the set volume of alkali into a conical flask using a pipette. Then you should add 3-4 drops of an indicator (e.g. phenolphthalein). Then, slowly add the acid to the alkali using a burtte, until the indicator changes colour - this is called the end point. You should note the exact number of acid that was needed for the indicator to change colour and react with the alkali. Next, carry out the reaction in a beaker, using the same volume of alkali and acid, but without the indicator so that the salt formed isn't contaminated with it. You should then transfer the solution containing the salt and water into an evaporating dish. Next, heat the solution by gently using a bunsen burner to evaporate some of the water. You will have to then leave the solution to cool to allow the salt to crystallise. Filter off the solid salt and then leave it to dry. Signup and view all the answers

Why should you repeat the reaction in a beaker without the indicator this time in method 2 of making soluble salts?

So that the salt formed won't be contaminated with it Signup and view all the answers

When making insoluble salts, what are the products of the reaction: Lead nitrate + Sodium chloride?

->Lead chloride + Sodium nitrate Signup and view all the answers

When making soluble salts, what are the products of the reaction: Magnesium oxide + Sulfuric acid?

-> Magnesium sulfate + Water Signup and view all the answers

When making soluble salts, what are the products of the reaction: Sodium hydroxide + Sulfuric acid?

-> Sodium sulfuric + Water Signup and view all the answers

What is another name for a hydroxide?

Alkali Signup and view all the answers

When making soluble salts, what are the products of the reaction: Sodium carbonate + Hydrochloric acid?

-> Sodium chloride + Water + Carbon dioxide Signup and view all the answers

When acid reacts with metal, what are the products of the reaction: Magnesium + Hydrochloric acid?

-> Magnesium chloride + Hydrogen Signup and view all the answers

Water forms when ions from the acid combines with ions (in metal oxide) or ions (in metal hydroxide) to form water.

hydrogen, oxide, hydroxide Signup and view all the answers

How does water form?

Water forms when hydrogen ions from the acid combines with oxide ions (in metal oxide) or hydroxide ions (in metal hydroxide) to form water. Signup and view all the answers

Salt is formed by replacing what with what?

Hydrogen ions with metal ions Signup and view all the answers

Carbon dioxide and water forms when what combines with what?

Replaced hydrogen ions combine with carbonate ions Signup and view all the answers

Match the base with its chemical symbol:

Hydroxide = OH⁻ Nitrate = NO₃⁻ Sulfate = SO₄²⁻ Sulfite = SO₃²⁻ Signup and view all the answers

Match the base with its chemical symbol:

Phosphate = PO₄³⁻ Nitrate = NO₃⁻ Carbonate = CO₃²⁻ Ammonium = NH₄⁺ Signup and view all the answers

Chemistry - Acids & Alkalis

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Questions and Answers

International hazard symbols indicate dangers with chemicals. So we know what to...

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

What does this symbol mean, what does it indicate the substance can do, and what precautions should you take when you see it?

What does this symbol mean, and what is its typical hazard?

What does this symbol mean, and what is its typical hazard?

What does this symbol mean, and what is its typical hazard?

Why would a hazard symbol of a 'flame' be on an ethanol bottle?

A concentrated solution is a _____ amount of dissolved solute in a given volume of water. A dilute solution is a _____ amount of dissolved solute in a given volume of water.

How could you create a dilute solution from a concentrated solution?

How could you create a concentrated solution from a dilute solution? (Select all that apply)

State the definition of a strong acid.

Select the examples of strong acids:

The pH values range from ___ in strong acids. The pH values range from ___ in weak acids.

What is the definition of a weak acid?

Select the examples of weak acids:

Hydrochloric acid is a solution of ____ acid and has a high _______ level. Therefore hydrochloric acid has ____ concentrations of hydrogen (H+) ions.

Ethanoic acid is a solution of ____ acid and has a low _______ level. Therefore ethanoic acid has ___ concentrations of hydrogen (H+) ions.

Explain why hydrochloric acid has a lower pH than ethanoic acid.

Explain why carbonic acid has a higher pH than sulfuric acid.

The higher the number of ______ ions in a certain volume, the _____ the hydrogen ion concentration, the more _____ the solution is, the lower the __ of the acidic solution.

What do pH scales measure?

Match the following types of solutions with their corresponding pH levels:

The lower the pH, the more _____ the solution is. The higher the pH, the more _____ the solution is.

Match the common acids with their correct symbol:

Match the common alkalis with their correct symbol:

Neutral solutions have an equal number/concentration of ______ and ______ ions.

What is an indicator?

Match the indicator with their colour when in an acidic solution:

Match the indicator with their colour when in an alkaline solution:

What is a base?

acid + base -> ___ + ____

A reaction between an acid and a base is called a ________ reaction.

Select the substances that can act as a base.

What is an alkali?

Match the following chemical reactions with their products:

A salt forms when _______ ions in acid are replaced by _____ ions or _______ ions.

Match the name of the acid with the type of salt produced:

Describe the process of the carbon dioxide test.

Describe the process of the hydrogen test.

When aqueous solutions are dissolved in water acid ____ and produces _______ ions. This means there is a _____ hydrogen ion concentration. This means that the solution is more _____ and the pH is _____.

When aqueous solutions are dissolved in water, alkalis produce _______ ions. This means there is a _____ hydroxide ion concentration. This means that the solution is more _____ and the pH is _____.

What are the two ways of making soluble salts?

Match the order of the steps with their description in relation to making insoluble salts:

Explain how you could go about making insoluble salts.

Match the method of making a soluble salt with when to use which one:

Match the method of making a soluble salt with its equation:

Explain how you could go about making soluble salts (method 1).

Why, when making a soluble salt, should you first heat the acid in a water bath?

Why should you leave some remaining base (metal oxide) at the bottom of the beaker when adding it slowly?

Explain how you could go about making soluble salts (method 2).

Why should you repeat the reaction in a beaker without the indicator this time in method 2 of making soluble salts?

When making insoluble salts, what are the products of the reaction: Lead nitrate + Sodium chloride?

When making soluble salts, what are the products of the reaction: Magnesium oxide + Sulfuric acid?

When making soluble salts, what are the products of the reaction: Sodium hydroxide + Sulfuric acid?

What is another name for a hydroxide?

When making soluble salts, what are the products of the reaction: Sodium carbonate + Hydrochloric acid?

When acid reacts with metal, what are the products of the reaction: Magnesium + Hydrochloric acid?

Water forms when ______ ions from the acid combines with ____ ions (in metal oxide) or ______ ions (in metal hydroxide) to form water.

How does water form?

Salt is formed by replacing what with what?

Carbon dioxide and water forms when what combines with what?

Match the base with its chemical symbol:

Match the base with its chemical symbol:

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Chemistry Acids and Alkalis Quiz

A concentrated solution is a _ amount of dissolved solute in a given volume of water. A dilute solution is a _ amount of dissolved solute in a given volume of water.

The pH values range from _ in strong acids. The pH values range from _ in weak acids.

Hydrochloric acid is a solution of acid and has a high _ level. Therefore hydrochloric acid has __ concentrations of hydrogen (H+) ions.

Ethanoic acid is a solution of acid and has a low _ level. Therefore ethanoic acid has _ concentrations of hydrogen (H+) ions.

The higher the number of ____ ions in a certain volume, the _ the hydrogen ion concentration, the more _ the solution is, the lower the of the acidic solution.

The lower the pH, the more _ the solution is. The higher the pH, the more _ the solution is.

Neutral solutions have an equal number/concentration of and ions.

acid + base -> _ + __

A salt forms when _____ ions in acid are replaced by _ ions or _____ ions.

When aqueous solutions are dissolved in water acid and produces _ ions. This means there is a _ hydrogen ion concentration. This means that the solution is more _ and the pH is ___.

When aqueous solutions are dissolved in water, alkalis produce _____ ions. This means there is a _ hydroxide ion concentration. This means that the solution is more _ and the pH is ___.

Water forms when ions from the acid combines with ions (in metal oxide) or ions (in metal hydroxide) to form water.