UPCAT Chemistry — Matter, Mixtures & MeasurementStudy Notes
Detailed study notes for UPCAT Chemistry — Matter, Mixtures & Measurement. These are the kind of notes you would take if you were reviewing with someone who has already scored well on the UPCAT: organised by what University of the Philippines tests first, followed by the nice-to-knows, and ending with the traps to avoid.
Exam context
On the UPCAT 2026, the Chemistry subtest carries a "Core" weight in University of the Philippines's pattern. Matter, Mixtures & Measurement lands at position 1st out of 7 in the standard review order. Target score is UPG ≤ 2.2 typical, and roughly 20 items come from Chemistry on a typical UPCAT paper.
Matter, Mixtures & Measurement - Study notes
Chemistry is the study of matter - everything around us that has mass and occupies space. Understanding the nature of matter, how substances combine to form mixtures, and how we measure chemical properties is fundamental to chemistry. This chapter explores the classification of matter, separation techniques for mixtures, and the importance of accurate measurement in chemistry. These concepts form the foundation for all chemical studies and are essential for success in college entrance examinations.
Summary
This chapter covers the fundamental concepts of matter, mixtures, and measurement in chemistry. Matter is anything with mass and volume, classified as pure substances (elements and compounds) or mixtures (homogeneous and heterogeneous). Separation techniques like filtration, distillation, and chromatography are chosen based on physical properties. Matter exists in four states with phase changes involving energy transfer. Chemical laws govern composition and reactions, while properties are classified as physical or chemical, intensive or extensive. Accurate measurement using the metric system, significant figures, and dimensional analysis is crucial for chemical studies. pH measures acidity and basicity, important for understanding chemical behavior. These concepts provide the foundation for advanced chemistry studies and are essential for college entrance examinations.
Sections
Chemistry is the branch of science that studies the properties, composition, structure, and changes in matter. Matter is defined as anything that has mass and occupies space (volume). All substances around us - from the air we breathe to the food we eat - are forms of matter. Matter exists in different states (solid, liquid, gas, and plasma) and can be classified based on its composition and properties. Understanding matter is crucial because it helps us explain how and why chemical reactions occur, how to separate substances, and how to measure their properties accurately.
Heading
What is Chemistry and Matter?
Examples
- Water (H2O) is matter because it has mass and takes up space
- Air is a mixture of gases including nitrogen, oxygen, and carbon dioxide
- Ice, water, and water vapor are the same substance in different states
- Salt dissolved in water forms a homogeneous mixture called brine
Key Points
- Chemistry studies the properties, composition, structure, and changes in matter
- Matter is anything that has mass and occupies space
- Matter exists in four states: solid, liquid, gas, and plasma
- Matter can be classified as pure substances or mixtures
- Understanding matter helps predict chemical behavior and reactions
Matter can be classified into two main categories: pure substances and mixtures. Pure substances have definite composition and distinct properties throughout the sample. They include elements (composed of the same type of atoms, like gold or oxygen) and compounds (made of two or more different atoms chemically combined, like water or carbon dioxide). Mixtures are combinations of two or more substances that are physically combined and can be separated by physical means. Mixtures are further classified as homogeneous (uniform appearance, like salt water) or heterogeneous (non-uniform, with visible components, like oil and water).
Heading
Classification of Matter
Examples
- Elements: Gold (Au), Iron (Fe), Oxygen (O2), Hydrogen (H2)
- Compounds: Water (H2O), Salt (NaCl), Carbon dioxide (CO2)
- Homogeneous mixtures: Air, sugar water, brass alloy
- Heterogeneous mixtures: Sand and water, oil and vinegar, granite rock
Key Points
- Pure substances have definite composition and distinct properties
- Elements cannot be broken down by chemical means
- Compounds are made of different atoms chemically combined
- Mixtures can be separated by physical means
- Homogeneous mixtures have uniform composition
- Heterogeneous mixtures have visible, distinct components
Mixtures are classified based on particle size and uniformity. Solutions are homogeneous mixtures where one substance (solute) is completely dissolved in another (solvent). Colloids contain particles larger than solutions but smaller than suspensions, and they show the Tyndall effect (scattering of light). Suspensions have large particles that settle over time. Understanding these classifications is important for separation techniques and predicting mixture behavior. Solubility rules help predict which substances will dissolve in water, with ionic compounds generally being soluble except for specific exceptions involving silver, mercury, lead, and certain polyatomic ions.
Heading
Types of Mixtures and Solutions
Examples
- Solutions: Salt water, sugar in coffee, vinegar (acetic acid in water)
- Colloids: Milk, mayonnaise, fog, butter, gelatin
- Suspensions: Muddy water, sand in water, oil and water
- Soluble compounds: NaCl, KBr, NH4NO3, Ca(NO3)2
- Insoluble compounds: AgCl, PbSO4, BaSO4, Mg(OH)2
Key Points
- Solutions have solute completely dissolved in solvent
- Colloids show Tyndall effect and don't settle
- Suspensions have large particles that settle over time
- Particle size determines mixture classification
- Solubility rules predict which ionic compounds dissolve
- Most alkali metals and ammonium compounds are soluble
Different separation techniques are used based on the physical properties of mixture components. Filtration separates solids from liquids using a porous barrier. Distillation separates liquids with different boiling points by heating and condensing. Chromatography separates substances based on their different rates of movement through a stationary phase. Other methods include decantation (based on density differences), sieving (based on particle size), centrifugation (using rotational force), and magnetic separation (for magnetic materials). The choice of separation method depends on the nature of the mixture and the physical properties of its components.
Heading
Separation Techniques for Mixtures
Examples
- Filtration: Separating sand from salt water
- Distillation: Separating alcohol from water
- Chromatography: Separating ink colors on paper
- Decantation: Separating oil from water
- Sieving: Separating different sized pebbles
- Magnetic separation: Separating iron filings from sand
Key Points
- Filtration separates solids from liquids using porous barriers
- Distillation uses different boiling points to separate liquids
- Chromatography separates based on different travel rates
- Decantation separates based on density differences
- Sieving separates based on particle size
- Method choice depends on mixture properties
Matter exists in four states: solid (definite shape and volume), liquid (definite volume, takes container shape), gas (takes container shape and volume), and plasma (superheated matter with charged particles). Phase changes are physical processes where matter transitions between states. Melting changes solid to liquid, freezing changes liquid to solid, evaporation changes liquid to gas, condensation changes gas to liquid, sublimation changes solid directly to gas, and deposition changes gas directly to solid. These changes involve energy absorption (endothermic) or release (exothermic) but don't change the substance's chemical identity.
Heading
States of Matter and Phase Changes
Examples
- Solid: Ice has fixed shape and volume
- Liquid: Water takes container shape but has fixed volume
- Gas: Water vapor fills entire container
- Plasma: Lightning, aurora borealis, stars
- Melting: Ice to water at 0°C
- Sublimation: Dry ice (solid CO2) directly to gas
Key Points
- Solids have definite shape and volume
- Liquids have definite volume but take container shape
- Gases take both container shape and volume
- Plasma contains charged ions and electrons
- Phase changes are physical, not chemical processes
- Energy is absorbed or released during phase changes
Fundamental laws govern chemical behavior. The Law of Conservation of Mass states that matter cannot be created or destroyed in chemical reactions. The Law of Definite Composition states that compounds always contain the same elements in the same proportions by mass. The Law of Multiple Proportions applies when elements form multiple compounds - the mass ratios form simple whole number relationships. Properties of matter are classified as physical (observed without changing composition) or chemical (related to chemical reactions). Physical properties can be intensive (independent of amount) or extensive (dependent on amount).
Heading
Chemical Laws and Properties
Examples
- Conservation: Burning wood - total mass of products equals reactants
- Definite composition: Water is always 11.19% H and 88.81% O by mass
- Multiple proportions: CO (carbon monoxide) vs CO2 (carbon dioxide)
- Physical properties: Density, melting point, color, hardness
- Chemical properties: Flammability, reactivity with acids, corrosion
- Intensive: Temperature, density; Extensive: Mass, volume
Key Points
- Mass is conserved in all chemical reactions
- Compounds have definite, constant composition
- Multiple compounds show simple mass ratios
- Physical properties don't change substance identity
- Chemical properties involve chemical reactions
- Intensive properties are independent of sample size
Accurate measurement is essential in chemistry. The metric system uses base units: meter (length), gram (mass), liter (volume), and Kelvin (temperature). Scientific notation helps express very large or small numbers. Significant figures indicate measurement precision - all non-zero digits are significant, zeros between non-zeros are significant, leading zeros are not significant, and trailing zeros after decimals are significant. Accuracy refers to closeness to true value, while precision refers to reproducibility of measurements. Dimensional analysis uses conversion factors to change units systematically.
Heading
Measurement in Chemistry
Examples
- Base units: 1 meter, 1 gram, 1 liter, 273.15 K (0°C)
- Scientific notation: 6.02 × 10²³ (Avogadro's number)
- Significant figures: 12.50 has 4 sig figs, 0.0120 has 3 sig figs
- Accurate but imprecise: Average close to true value but scattered results
- Precise but inaccurate: Consistent results far from true value
- Conversion: 1000 mL = 1 L, 1000 g = 1 kg
Key Points
- Metric system uses meter, gram, liter, and Kelvin as base units
- Scientific notation expresses very large or small numbers
- Significant figures indicate measurement precision
- Accuracy measures closeness to true value
- Precision measures reproducibility of results
- Dimensional analysis uses conversion factors for unit changes
pH is a measure of hydrogen ion concentration in solutions. The pH scale ranges from 0-14, with 7 being neutral. Acids have pH < 7, release H+ ions, turn blue litmus red, and taste sour. Bases have pH > 7, release OH- ions, turn red litmus blue, and feel slippery. The pH formula is pH = -log[H+], and pH + pOH = 14 at 25°C. Understanding pH is important for predicting chemical behavior, especially in biological systems and industrial processes. Strong acids and bases ionize completely, while weak ones only partially ionize.
Heading
pH and Acid-Base Properties
Examples
- Strong acids: HCl (stomach acid, pH ~1), H2SO4 (battery acid)
- Weak acids: CH3COOH (vinegar, pH ~2.4), citric acid (lemon juice)
- Neutral: Pure water (pH = 7), salt solutions
- Weak bases: NH3 (ammonia), NaHCO3 (baking soda, pH ~9)
- Strong bases: NaOH (lye, pH ~13), Ca(OH)2 (lime water)
- pH calculation: If [H+] = 1 × 10⁻³, then pH = 3
Key Points
- pH measures hydrogen ion concentration
- pH scale ranges from 0 (most acidic) to 14 (most basic)
- Neutral solutions have pH = 7
- Acids release H+ ions and have pH < 7
- Bases release OH- ions and have pH > 7
- pH + pOH = 14 at standard conditions
Ready to practise for the UPCAT 2026?
Super Tutor's AI review plan adapts to your weak areas and builds a weekly practice schedule around your target UPCAT exam date.