Properties of the substances
what is chemistry;
which safety rules should be followed in the school chemical laboratory;
which vessels and what equipment should be used to perform a specific laboratory activity;
how to handle substances and preparations marked with warning pictograms.
define the term substance;
present the division of properties of substances;
examine and describe the properties of selected substances.
Does the term substance always mean the same?
In everyday language substances are elements of nature that surround us, e.g. water, air, wood in the fireplace, and spices used in the kitchen. However, this is not a correct term with regards to chemistry. SubstanceSubstance is the type of matter with a constant chemical composition, with a set of specific properties, due to which we can recognize it.
Substances are: sugar, rock salt, iron, oxygen, pure water so‑called distilled water (in contrast to sea water or tap water).
Explain how can you use these substances in your everyday life. Describe the properties of these substances and formulate conclusions.
Is the application of various objects related to the properties of the materials of which these are made?
Select one of the hypotheses and verify it*.*
The application of objects is related to the properties of the materials of which these are made. The application of objects is not related to the properties of the materials of which these are made.
wooden knife (for spreading),
plastic knife,
metal kitchen knife,
cutting board,
apple.
Put apple on the cutting board.
Try to cut it in sequence with knives made of various materials (wood, plastic and metal).
The usefulness of objects is related to the properties of the materials of which these are made. Structural elements are made of high strength materials. Pots are made of materials that conduct heat well, and handles – from insulators protecting against burns. Good and bad heat conduction are the properties of matter that affect its use. Some features can be measured, others only described. Measurements are made under the same conditions (at room temperature and under normal pressure), which makes it possible to compare results.
Recall from the biology lessons, what the world around us is made of.
Look at illustrations of sample products (candyfloss, pins, glass chandelier, silver coin, metal gutter) and specify what substances were these made of. Write down the answers here or in the notebook.
All substances have specific properties. We can examine them with senses (e.g. to see, hear, smell) or with special instruments, which allows us to distinguish a given substance from another one. The properties of the substance can be divided into:
qualitative – those that cannot be expressed in numbers (e.g. taste, smell);
quantitative – those that can be measured and described by numbers (e.g., density, boiling point, melting point).
and:
Properties of substances
physical properties
characteristics of the substance: state of aggregation; colour; type of surface: shiny, matt, rough, porous; hardness; change in the shape of the body under the influence of forces: brittleness; resilience; malleability; solubility in water and other solvents; heat conductivity; electrical conductivity; magnetic properties; boiling point; melting temperature; density.
chemical properties
characteristics of substances that can be determined based on their behavior towards other substances; the chemical properties include, among others: combustibility,
toxicity, reactivity, smell, taste.
Write examples of qualitative, quantitative, physical and chemical properties of the substances and place them on the board.
Complete the definition.
Substance is liquid, ............ or solid with characteristic ................ and chemical properties due to which it can be identified.
What substances make up the objects indicated in the illustration? In the right places write down their names, e.g. steel, linen or paper.
What is the common property of the pairs of items in the table? Pair the nouns with the adjectives: hardness, flexibility, sweet taste.
| Common property | Common property | Common property |
|---|---|---|
| steel | caoutchouc | sugar |
| granite | nylon | glycerol |
Match the pairs: English words with Polish definition.
cechy substancji, które można określić na podstawie jej zachowania wobec innych substancji; do właściwości chemicznych zaliczamy m.in.: palność, reaktywność, zapach, smak, charakterystyczne cechy danej substancji, takie jak: stan skupienia, barwa, rozpuszczalność (rozpuszczanie to zjawisko fizyczne), przewodnictwo elektryczne, przewodnictwo cieplne, temperatury wrzenia i topnienia, twardość, kruchość, kowalność, połysk, gęstość, właściwości magnetyczne, rodzaj jednorodnej materii (o stałym składzie chemicznym) o określonych właściwościach (cechach charakterystycznych, np. stan skupienia, w danych warunkach, barwa, twardość, palność), np. woda, żelazo, miedź, glin
| substance | |
| physical properties of the substance | |
| chemical properties of the substance |
Summary
The world consists of various substances that have a permanent composition and specific properties.
Substances can be identified based on their properties.
The application of substances result from their characteristic properties, both physical and chemical (e.g. sugar is sweet, therefore we use it for sweetening, carbon dioxide does not support combustion, so it is used as a fire extinguisher in some types of fire extinguishers).
Key words
Properties of the substances, physical properties
Glossary
substancja – rodzaj jednorodnej materii (o stałym składzie chemicznym) o określonych właściwościach (cechach charakterystycznych, np. stan skupienia, w danych warunkach, barwa, twardość, palność), np. woda, żelazo, miedź, glin
właściwości fizyczne substancji – charakterystyczne cechy danej substancji, takie jak: stan skupienia, barwa, rozpuszczalność (rozpuszczanie to zjawisko fizyczne), przewodnictwo elektryczne, przewodnictwo cieplne, temperatury wrzenia i topnienia, twardość, kruchość, kowalność, połysk, gęstość, właściwości magnetyczne
właściwości chemiczne substancji – cechy substancji, które można określić na podstawie jej zachowania wobec innych substancji; do właściwości chemicznych zaliczamy m.in.: palność, reaktywność, zapach, smak