Acids, Alkalis & pH
CONCEPTUALDefine acids and alkalis in terms of hydrogen ion concentration, describe the pH scale (0–14), and explain how indicators are used to identify and measure acidity or alkalinity
Mastery Evidence
- States that acids have pH below 7, alkalis have pH above 7, and neutral is pH 7
- Explains what hydrogen ions (H⁺) have to do with acidity
- Names common indicators (litmus, universal indicator) and describes colour changes
- Identifies everyday acids (vinegar, lemon juice) and alkalis (bleach, bicarbonate of soda)
Assessment Prompt
“If [child] used a piece of universal indicator paper to test lemon juice and baking soda solution, could they predict what colour each would turn and explain what that tells you about each substance?”
Curriculum Standards1 alignment
KS3.Sci.Chem.CR.2The national curriculum in Englanddefining acids and alkalis in terms of the hydrogen ion concentration, the use of the pH scale for measuring acidity/alkalinity; and indicators
Prerequisites2
- Coral Bleaching & AcidificationsoftAges 12—13
- Atoms, Elements & CompoundssoftAges 11—12
Show full prerequisite tree
- Coral Bleaching & Acidification soft
KS3 acids/pH and carbonic acid chemistry underpins the ocean acidification mechanism that dissolves coral skeletons
- Ocean Currents and Global Heat hard
Coral reef bleaching and ocean acidification depends on understanding thermohaline circulation and ocean heat dynamics
- Where water is found on Earth soft
Five oceans builds on curriculum concept of where water is found on Earth
- Shapes of land and water hard
Must know land and water features before learning where water is found on Earth
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Heating & Cooling Changes soft
Understanding state changes supports knowing water as solid (ice) and liquid
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Weather vs Climate soft
Ocean-climate connection benefits from understanding weather vs climate distinction
- Seasons & Weather Patterns soft
Climate as long-term patterns benefits from knowing seasonal patterns
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Geography & Local Weather hard
Climate concept requires knowing that different places have different typical weather
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Tides, Waves & Currents hard
Ocean-climate connection builds on knowing about currents and evaporation
- Whales & Dolphins Are Mammals hard
Classifying marine mammals vs fish builds on whale/dolphin are mammals concept
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Ocean Animal Variety hard
Understanding zones requires knowing ocean has diverse life at different depths
- Changing Environments soft
Ocean ecosystems concept enriched by curriculum concept that environments change
- Habitats & Basic Needs hard
Must understand how habitats support organisms before understanding what happens when they change
- Where Are the Poles? soft
Polar regions enrich the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary hard
Describing how habitats provide for basic needs requires habitat, environment, conditions, shelter vocabulary
- What Is a Rainforest? soft
Rainforest habitat knowledge enriches the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- What Living Things Need hard
Must know basic needs of organisms before understanding how habitats provide for those needs
- Living Things Vocabulary soft
Describing what plants and animals need to survive uses life processes vocabulary: nutrition, growth, sensitivity
- Living, Dead & Never Alive hard
Must distinguish living from non-living before understanding habitats that support living things
- Living Things Vocabulary hard
Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
- Common minibeasts: naming and recognising hard
Must recognise common minibeasts before exploring where each type lives
- Simple Food Chains soft
Food chain knowledge helps understand knock-on effects of environmental change
- Herbivores, Carnivores & Omnivores hard
Must know carnivore/herbivore/omnivore to understand food chains
- Habitats & Basic Needs hard
Must know about habitats and interdependence before learning food chains
- Where Are the Poles? soft
Polar regions enrich the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary hard
Describing how habitats provide for basic needs requires habitat, environment, conditions, shelter vocabulary
- What Is a Rainforest? soft
Rainforest habitat knowledge enriches the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- What Living Things Need hard
Must know basic needs of organisms before understanding how habitats provide for those needs
- Living Things Vocabulary soft
Describing what plants and animals need to survive uses life processes vocabulary: nutrition, growth, sensitivity
- Living, Dead & Never Alive hard
Must distinguish living from non-living before understanding habitats that support living things
- Living Things Vocabulary hard
Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
- Common minibeasts: naming and recognising hard
Must recognise common minibeasts before exploring where each type lives
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Minibeasts in the food chain soft
Garden minibeast food chains provide concrete examples for curriculum simple-food-chains
- Common minibeasts: naming and recognising hard
Must know common minibeasts before placing them in food chains
- Rainforest Animals soft
Rainforest animals provide rich examples for simple food chains (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary soft
Discussing how environments change and pose dangers uses habitat and conditions vocabulary
- Predator Loss and Ecosystem Effects hard
Coral reef crisis as a case study in ecosystem collapse connects to broader trophic cascade and food web disruption
- Whales & Dolphins Are Mammals hard
Classifying marine mammals vs fish builds on whale/dolphin are mammals concept
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Whales & Dolphins Are Mammals hard
Classifying marine mammals vs fish builds on whale/dolphin are mammals concept
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Ocean Animal Variety hard
Understanding zones requires knowing ocean has diverse life at different depths
- Changing Environments soft
Ocean ecosystems concept enriched by curriculum concept that environments change
- Habitats & Basic Needs hard
Must understand how habitats support organisms before understanding what happens when they change
- Where Are the Poles? soft
Polar regions enrich the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary hard
Describing how habitats provide for basic needs requires habitat, environment, conditions, shelter vocabulary
- What Is a Rainforest? soft
Rainforest habitat knowledge enriches the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- What Living Things Need hard
Must know basic needs of organisms before understanding how habitats provide for those needs
- Living Things Vocabulary soft
Describing what plants and animals need to survive uses life processes vocabulary: nutrition, growth, sensitivity
- Living, Dead & Never Alive hard
Must distinguish living from non-living before understanding habitats that support living things
- Living Things Vocabulary hard
Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
- Common minibeasts: naming and recognising hard
Must recognise common minibeasts before exploring where each type lives
- Simple Food Chains soft
Food chain knowledge helps understand knock-on effects of environmental change
- Herbivores, Carnivores & Omnivores hard
Must know carnivore/herbivore/omnivore to understand food chains
- Habitats & Basic Needs hard
Must know about habitats and interdependence before learning food chains
- Where Are the Poles? soft
Polar regions enrich the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary hard
Describing how habitats provide for basic needs requires habitat, environment, conditions, shelter vocabulary
- What Is a Rainforest? soft
Rainforest habitat knowledge enriches the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- What Living Things Need hard
Must know basic needs of organisms before understanding how habitats provide for those needs
- Living Things Vocabulary soft
Describing what plants and animals need to survive uses life processes vocabulary: nutrition, growth, sensitivity
- Living, Dead & Never Alive hard
Must distinguish living from non-living before understanding habitats that support living things
- Living Things Vocabulary hard
Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
- Common minibeasts: naming and recognising hard
Must recognise common minibeasts before exploring where each type lives
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Minibeasts in the food chain soft
Garden minibeast food chains provide concrete examples for curriculum simple-food-chains
- Common minibeasts: naming and recognising hard
Must know common minibeasts before placing them in food chains
- Rainforest Animals soft
Rainforest animals provide rich examples for simple food chains (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary soft
Discussing how environments change and pose dangers uses habitat and conditions vocabulary
- Ocean Ecosystems hard
Coral reef collapse and marine biodiversity depends on ocean ecosystem structure
- Whales & Dolphins Are Mammals hard
Classifying marine mammals vs fish builds on whale/dolphin are mammals concept
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Ocean Animal Variety hard
Understanding zones requires knowing ocean has diverse life at different depths
- Changing Environments soft
Ocean ecosystems concept enriched by curriculum concept that environments change
- Habitats & Basic Needs hard
Must understand how habitats support organisms before understanding what happens when they change
- Where Are the Poles? soft
Polar regions enrich the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary hard
Describing how habitats provide for basic needs requires habitat, environment, conditions, shelter vocabulary
- What Is a Rainforest? soft
Rainforest habitat knowledge enriches the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- What Living Things Need hard
Must know basic needs of organisms before understanding how habitats provide for those needs
- Living Things Vocabulary soft
Describing what plants and animals need to survive uses life processes vocabulary: nutrition, growth, sensitivity
- Living, Dead & Never Alive hard
Must distinguish living from non-living before understanding habitats that support living things
- Living Things Vocabulary hard
Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
- Common minibeasts: naming and recognising hard
Must recognise common minibeasts before exploring where each type lives
- Simple Food Chains soft
Food chain knowledge helps understand knock-on effects of environmental change
- Herbivores, Carnivores & Omnivores hard
Must know carnivore/herbivore/omnivore to understand food chains
- Habitats & Basic Needs hard
Must know about habitats and interdependence before learning food chains
- Where Are the Poles? soft
Polar regions enrich the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary hard
Describing how habitats provide for basic needs requires habitat, environment, conditions, shelter vocabulary
- What Is a Rainforest? soft
Rainforest habitat knowledge enriches the curriculum habitats topic (exploratory age 5 -> curriculum age 6)
- What Living Things Need hard
Must know basic needs of organisms before understanding how habitats provide for those needs
- Living Things Vocabulary soft
Describing what plants and animals need to survive uses life processes vocabulary: nutrition, growth, sensitivity
- Living, Dead & Never Alive hard
Must distinguish living from non-living before understanding habitats that support living things
- Living Things Vocabulary hard
Comparing living, dead, and never-been-alive things requires the life processes vocabulary to give reasons
- Common minibeasts: naming and recognising hard
Must recognise common minibeasts before exploring where each type lives
- Ocean Animal Variety soft
Food chains benefit from knowing the variety of animals that eat each other
- Minibeasts in the food chain soft
Garden minibeast food chains provide concrete examples for curriculum simple-food-chains
- Common minibeasts: naming and recognising hard
Must know common minibeasts before placing them in food chains
- Rainforest Animals soft
Rainforest animals provide rich examples for simple food chains (exploratory age 5 -> curriculum age 6)
- Habitat Vocabulary soft
Discussing how environments change and pose dangers uses habitat and conditions vocabulary
- Atoms, Elements & Compounds soft
Acids are defined in terms of hydrogen ions — the concept of ions and atomic structure is needed
- The Particle Model hard
Atoms and molecules are the particles referred to in the particle model — builds directly on it
- Drawing Particle Diagrams hard
Using the particle model to explain density, compressibility, and anomalous expansion requires fluent reading and drawing of particle diagrams
- Matter Is Made of Particles hard
KS3 particle model extends US KS2 introduction to matter as particles too small to see
- Drawing Particle Diagrams hard
Developing a model of matter as particles too small to see is built on the particle diagram representation
- Heating & Cooling Changes hard
Must observe state changes before explaining them with particle model
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Solids, Liquids & Gases hard
Must understand observable states of matter before modelling them with particles
- States of Matter Vocabulary hard
Comparing and grouping materials as solids, liquids, or gases requires the naming vocabulary for the three states
- Drawing Particle Diagrams hard
Comparing and grouping solids, liquids, and gases by properties is greatly aided by the particle diagram representation
- Heating & Cooling Changes hard
Must classify states of matter before understanding changes between states
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Grouping Materials hard
Must group materials by properties before classifying into three states of matter
- States of Matter Vocabulary soft
Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
- Changing Shapes of Solids soft
Changing shapes of solids provides context for understanding solid properties
- Describing Material Properties hard
Must know material properties before investigating how shapes change
- States of Matter Vocabulary soft
Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
- Solids, Liquids & Gases hard
KS3 particle model extends KS2 classification of solids, liquids and gases by observable properties
- States of Matter Vocabulary hard
Comparing and grouping materials as solids, liquids, or gases requires the naming vocabulary for the three states
- Drawing Particle Diagrams hard
Comparing and grouping solids, liquids, and gases by properties is greatly aided by the particle diagram representation
- Heating & Cooling Changes hard
Must classify states of matter before understanding changes between states
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Grouping Materials hard
Must group materials by properties before classifying into three states of matter
- States of Matter Vocabulary soft
Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
- Changing Shapes of Solids soft
Changing shapes of solids provides context for understanding solid properties
- Describing Material Properties hard
Must know material properties before investigating how shapes change
- States of Matter Vocabulary soft
Describing physical properties of materials uses solid/liquid/gas vocabulary introduced in the states of matter LANGUAGE node
Unlocks1
- Acid Reactions & SaltshardAges 12—13