GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxidePractice these equations in FULL – you choose the level of difficulty;Practice these equations in FULL – you choose the level of difficulty;

1.1. Thermal decomposition of magnesium carbonateThermal decomposition of magnesium carbonate2.2. Calcium added to hydrochloric acidCalcium added to hydrochloric acid3.3. Zinc metal added to sulphuric acidZinc metal added to sulphuric acid4.4. Calcium oxide is added to water to form a single compoundCalcium oxide is added to water to form a single compound5.5. Thermal decomposition of calcium carbonateThermal decomposition of calcium carbonate6.6. Zinc metal added to hydrochloric acidZinc metal added to hydrochloric acid7.7. Calcium is added to waterCalcium is added to water8.8. Magnesium metal is burnt Magnesium metal is burnt 9.9. Hydrogen gas is added to chlorine gasHydrogen gas is added to chlorine gas10.10. Calcium is added to oxygen gasCalcium is added to oxygen gas11.11. Magnesium metal is added to hydrochloric acidMagnesium metal is added to hydrochloric acid

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide

1.1. MgCOMgCO33 (s) (in heat forms) MgO (s) + CO (s) (in heat forms) MgO (s) + CO22 (g) (g)

2.2. Ca (s) + 2HCl (l) (forms) CaClCa (s) + 2HCl (l) (forms) CaCl22 (s) + H (s) + H22 (g) (g)

3.3. Zn (s) + HZn (s) + H22SOSO44 (l) (forms) ZnSO (l) (forms) ZnSO44 (l) + H (l) + H2 2 (g)(g)

4.4. CaO (s) + HCaO (s) + H220 (l) (forms) Ca(OH)0 (l) (forms) Ca(OH)22 (l) (l)

5.5. CaCOCaCO33 (s) (in heat forms) CaO (s) + CO (s) (in heat forms) CaO (s) + CO22 (g) (g)

6.6. Zn (s) + 2HCl (l) (forms) ZnClZn (s) + 2HCl (l) (forms) ZnCl22 (l) + H (l) + H2 2 (g)(g)

7.7. Ca (s) + HCa (s) + H220 (l) (forms) CaO (s) + H0 (l) (forms) CaO (s) + H22 (g) (g)

8.8. 2Mg (s) + O2Mg (s) + O22 (g) (forms) 2MgO (s) (g) (forms) 2MgO (s)

9.9. HH22 (g) + Cl (g) + Cl22 (g) (forms) 2HCl (l) (g) (forms) 2HCl (l)

10.10. 2Ca (s) + O2Ca (s) + O22 (g) (forms) 2CaO (s) (g) (forms) 2CaO (s)

11.11. Mg (s) + 2HCl (l) (forms) MgClMg (s) + 2HCl (l) (forms) MgCl22 (l) + H (l) + H2 2 (g)(g)

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide

Key words; lime water, mortar, slaked lime

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide

Learning Objectives:

By the end of the lesson I can: • Describe what slaked lime is and how it is Describe what slaked lime is and how it is produced.produced.Quicklime (calcium oxide) reacts with water to produce Quicklime (calcium oxide) reacts with water to produce slaked lime (calcium hydroxide).slaked lime (calcium hydroxide).••Explain the processes involved to make lime Explain the processes involved to make lime mortar.mortar. Mortar can be made by mixing slaked lime (calcium hydroxide) with sand and water.• • Limestone and its products have many uses, Limestone and its products have many uses, including slaked lime, mortar, cement and glass.including slaked lime, mortar, cement and glass.• • Atoms and symbols are used to represent and Atoms and symbols are used to represent and explain what is happening to the substances in explain what is happening to the substances in chemical reactions.chemical reactions.

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide

Limestone is a metamorphic rock and is made of the pure element, calcium carbonate.

What’s wrong with this sentence?

•Limestone is a sedimentary rock•It is mainly made up of calcium carbonate

•Calcium carbonate is a compound•It is actually a mixture of substances

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide

CaCOCaCO33

CaOCaO

Ca(OH)Ca(OH)22

COCO22

What is the chemical & common names for each substance?

Chemical: Calcium Carbonate

Common: Limestone/Chalk/Marble

Chemical: Calcium Oxide

Common: Quicklime

Chemical: Calcium Hydroxide

Common: Slaked Lime (or Limewater when in solution)

Chemical: Carbon dioxide

Common: Carbon dioxide

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide Limestone Cycle:

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxideLimestone Cycle:

When limestone (calcium carbonate) is heated strongly, it decomposes to give solid quicklime (calcium oxide) and carbon dioxide gas. When a small amount of water is added to quicklime it gives slaked lime (calcium hydroxide). If a lot of water is added to the slaked lime a solution of lime water or calcium hydroxide is formed. If carbon dioxide is bubbled through lime water, limestone is formed again, along with water.

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide Limestone Cycle:

Carbon Carbon DioxideDioxide

QuicklimQuicklimee

WateWaterr

Slaked Slaked limelime

Lime Lime waterwater

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxideAim: To investigate the limestone cycleEquipment:• Gauze, Tripod, bunsen burner & heat proof mat• Tongs, glass rod, pipette, straw• 2xboiling tubes, test tube rack• Filter funnel & filter paper• Calcium carbonate, waterMethod:

1. Place a piece of CaCO3 on the gauze mat & strongly heat the edge until it has been white/orange hot for a few minutes. What type of reaction have you just completed? BE SAFE: CaO holds it heat for a long time & are basic –harmful

2. Using tongs, transfer the CaO to a boiling tube, add afew drops of water & observe. What happened?

3. Fill the boiling tube till its 1/3 full and shake gently. BE SAFE: When water is added to CaO it will spit – so be sure to be wearing goggles!

4. Filter the mixture and keep the filtrate. What is the name of the filtrate?5. Submerge a straw into the filtrate & gently blow. If the solution turns cloudy

then the cycle has been completed successfully. Well Done!Add observations, word & symbol equations to your limestone cycle diagramAdd observations, word & symbol equations to your limestone cycle diagram

The The LimestonLimestone Cyclee Cycle

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxideCommon Name: QUICKLIME Chemical Name: CALCIUM OXIDEMolecular formula: CaOCalcium carbonate calcium oxide (s) + carbon dioxide (g)CaCO3(s) CaO (s) + CO2 (g)

Common Name: SLAKED LIME Chemical Name: CALCIUM HYDROXIDEMolecular formula: Ca(OH)2

Calcium oxide (s) + water (l) calcium hydroxide (s)CaO (s) + H2O (l) Ca(OH)2 (s)

Common Name: LIMEWATER Molecular formula: Ca(OH)2 (aq)Chemical Name: CALCIUM HYDROXIDE IN SOLUTIONCalcium hydroxide (s) + water (l) calcium hydroxide (s)Ca(OH)2 (s) + H2O (l) Ca(OH)2 (aq)

Common Name: LIMESTONE Chemical Name: CALCIUM CARBONATEMolecular formula: CaCO3

Calcium hydroxide (aq) + carbon dioxide (g) calcium carbonate (s) + water (l)Ca(OH)2 (aq) + CO2 (g) CaCO3 (s) + H2O (l)

GCSE Core Chemistry

Exam tip; Make sure you can write balanced equations for the reactions of quicklime with water & slaked lime with carbon

dioxide

Learning Objectives:

By the end of the lesson I can: • Describe what slaked lime is and how it is Describe what slaked lime is and how it is produced.produced.Quicklime (calcium oxide) reacts with water to produce Quicklime (calcium oxide) reacts with water to produce slaked lime (calcium hydroxide).slaked lime (calcium hydroxide).••Explain the processes involved to make lime Explain the processes involved to make lime mortar.mortar. Mortar can be made by mixing slaked lime (calcium hydroxide) with sand and water.• • Limestone and its products have many uses, Limestone and its products have many uses, including slaked lime, mortar, cement and glass.including slaked lime, mortar, cement and glass.• • Atoms and symbols are used to represent and Atoms and symbols are used to represent and explain what is happening to the substances in explain what is happening to the substances in chemical reactions.chemical reactions.