Chapter 3 SABIS Grade 10 Part 2

🧐 Lesson 11 🧐

Chapter Three Part Two: Identifying Substances and Mixtures

🎈 Prerequisite Quiz:🔹 Q1: 🤔 What is a pure substance? Ⓐ A substance that consists of multiple types of atoms. Ⓑ A substance that is composed of only one type of atom. Ⓒ A substance that cannot be broken down into simpler substances. Ⓓ Both B and C

Answer: Ⓓ Both B and C. 👍 A pure substance is composed of only one type of atom and cannot be broken down into simpler substances.

🔹 Q2: 🤔 Which state of matter consists of atoms tightly packed together? Ⓐ Gas Ⓑ 🎯 Solid Ⓒ Liquid Ⓓ Plasma

Answer: Ⓑ Solid. 👍 In solids, atoms are tightly packed together.

🔹 Q3: 🤔 What is a molecule? Ⓐ A single type of atom. Ⓑ 🎯 A group of atoms bonded together. Ⓒ A group of elements combined together. Ⓓ A single type of element.

Answer: Ⓑ A group of atoms bonded together. 👍 A molecule is a group of atoms bonded together.

🔹 Q4: 🤔 What is a homogeneous mixture? Ⓐ A mixture where you can identify individual components. Ⓑ 🎯 A mixture that has a uniform composition throughout. Ⓒ A mixture that has different components in different phases. Ⓓ None of the above.

Answer: Ⓑ A mixture that has a uniform composition throughout. 👍 A homogeneous mixture has a uniform composition throughout.

🔹 Q5: 🤔 What is a heterogeneous mixture? Ⓐ 🎯 A mixture where you can identify individual components. Ⓑ A mixture that has a uniform composition throughout. Ⓒ A mixture that has different components in different phases. Ⓓ None of the above.

Answer: Ⓐ A mixture where you can identify individual components. 👍 A heterogeneous mixture is a mixture where you can identify individual components.

🔹 Q6: 🤔 What are physical properties? Ⓐ 🎯 Properties that can be observed without changing the identity of the substance. Ⓑ Properties that can only be observed during a chemical reaction. Ⓒ Properties that change the identity of the substance. Ⓓ None of the above.

Answer: Ⓐ Properties that can be observed without changing the identity of the substance. 👍 Physical properties can be observed without changing the identity of the substance.

🔹 Q7: 🤔 How can substances be separated in a mixture? Ⓐ 🎯 By physical means. Ⓑ By chemical means. Ⓒ Both A and B. Ⓓ None of the above.

Answer: Ⓐ By physical means. 👍 Substances in a mixture can be separated by physical means.

🔹 Q8: 🤔 What is the basic unit of a chemical element? Ⓐ Molecule Ⓑ Compound Ⓒ 🎯 Atom Ⓓ Particle

Answer: Ⓒ Atom. 👍 The basic unit of a chemical element is an atom.

🔹 Q9: 🤔 What does it mean when a substance has a fixed composition? Ⓐ It has the same proportion of elements regardless of the sample size. Ⓑ It has different proportions of elements depending on the sample size. Ⓒ It cannot be separated into its components. Ⓓ 🎯 Both A and C.

Answer: Ⓓ Both A and C. 👍 When a substance has a fixed composition, it means it has the same proportion

🧐 The Lesson:

Think of pure substances like your best friends 😁, you can always identify them based on their unique characteristics 🧑👧. Similarly, we identify pure substances through their physical constants such as boiling point, melting point, etc 🌡️.

A pure substance can either be an element or a compound. An element is like a super VIP person 👑, they cannot be split into simpler substances by physical means or through chemical reactions. It's a pure substance made up of one kind of atoms, pretty unique huh?

On the other hand, a compound is like a football team ⚽, where you've got different players (atoms) working together. It's a pure substance containing more than one type of atoms. Some compounds don't even form molecules! For example, table salt (NaCl) and sand (SiO2).

Now, let's talk about mixtures 🍕. Mixtures are like a pizza, made up of at least two different ingredients (pure substances). They don't have a fixed composition; you can put whatever toppings you like on your pizza!

You can have homogeneous mixtures (solutions) 🥤, where all components mix so well, they exist in one phase. Just like a well-blended smoothie, you can't pick out individual fruits!

But sometimes, you get heterogeneous mixtures 🥗, where components exist in more than one phase. Like a salad, where you can see and pick out different ingredients.

Topics included

🔍 Topic 1: Pure Substances and Their Identification

Pure substances 🧪, like your best friends, have unique characteristics that can be used to identify them. These are called physical constants and include properties like boiling point, melting point, etc.

🔍 Topic 2: Elements

Elements 🌟 are like super VIPs; they can't be broken down into simpler substances, not even by chemical reactions. They are a pure substance made up of only one kind of atoms.

🔍 Topic 3: Compounds

Compounds are like a soccer team ⚽, with different types of atoms (players) working together. They're a pure substance made up of more than one type of atoms, and sometimes they don't even form molecules (like table salt or sand).

🔍 Topic 4: Mixtures

Mixtures 🍕 are like pizzas, consisting of at least two different ingredients (pure substances). The composition of a mixture is not fixed; it can vary depending on the proportions of the components.

🔍 Topic 5: Homogeneous Mixtures

Homogeneous mixtures 🥤 are like a well-blended smoothie. All the components are so well mixed, they exist in a single phase, and you can't pick out individual ingredients.

🔍 Topic 6: Heterogeneous Mixtures

Heterogeneous mixtures 🥗 are like salads, where the different components exist in more than one phase. You can see and pick out different ingredients.

End of Lesson Quiz:

🔹 Q1: 🤔 What distinguishes a pure substance from a mixture? Ⓐ A pure substance cannot be separated into its components, but a mixture can. Ⓑ A pure substance has a fixed composition, but a mixture doesn't. Ⓒ Both A and B. Ⓓ Neither A nor B.

Answer: Ⓒ Both A and B. 👍 A pure substance cannot be separated into its components and has a fixed composition, while a mixture can be separated and its composition can vary.

🔹 Q2: 🤔 An element is... Ⓐ A type of mixture. Ⓑ 🎯 A pure substance made up of one kind of atoms. Ⓒ A type of compound. Ⓓ A mixture of different atoms.

Answer: Ⓑ A pure substance made up of one kind of atoms. 👍 An element is a pure substance made up of one kind of atoms.

🔹 Q3: 🤔 A compound is... Ⓐ A mixture of two or more elements. Ⓑ A pure substance made up of one kind of atoms. Ⓒ 🎯 A pure substance containing more than one type of atoms. Ⓓ None of the above.

Answer: Ⓒ A pure substance containing more than one type of atoms. 👍 A compound is a pure substance that contains more than one type of atoms.

🔹 Q4: 🤔 Which of the following is a homogeneous mixture? Ⓐ Sand and water. Ⓑ Oil and water. Ⓒ 🎯 Salt dissolved in water. Ⓓ A bowl of fruit salad.

Answer: Ⓒ Salt dissolved in water. 👍 Salt dissolved in water is a homogeneous mixture as it has a uniform composition throughout.

🔹 Q5: 🤔 Which of the following is a heterogeneous mixture? Ⓐ 🎯 A bowl of fruit salad. Ⓑ Salt dissolved in water. Ⓒ A glass of lemonade. Ⓓ Sugar dissolved in tea.

Answer: 🎯 A bowl of fruit salad. 👍 A bowl of fruit salad is a heterogeneous mixture as you can identify individual components.

🔹 Q6: 🤔 What is the difference between homogeneous and heterogeneous mixtures? Ⓐ Homogeneous mixtures contain one type of particle, heterogeneous mixtures contain two. Ⓑ Homogeneous mixtures exist in one phase, heterogeneous mixtures in more than one phase. Ⓒ Homogeneous mixtures can't be separated, heterogeneous mixtures can. Ⓓ Homogeneous mixtures are always liquids, heterogeneous mixtures can be any state of matter.

Answer: Ⓑ Homogeneous mixtures exist in one phase, heterogeneous mixtures in more than one phase. 👍

🔹 Q7: 🤔 Are all compounds made of molecules? Ⓐ Yes. Ⓑ No. Ⓒ Only if they are made from nonmetals. Ⓓ Only if they are made from metals.

Answer: Ⓑ No. 👍 Some compounds, such as those formed from metals and nonmetals (e.g. NaCl), don't form molecules.

🔹 Q8: 🤔 Pure substances have a fixed... Ⓐ Color. Ⓑ Smell. Ⓒ Taste. Ⓓ Composition.

Answer: Ⓓ Composition. 👍 The composition of a pure substance is fixed and doesn't vary.

🔹 Q9: 🤔 Mixtures have a fixed... Ⓐ Composition. Ⓑ Color. Ⓒ 🎯 None of the above. Ⓓ All of the above.

Answer: Ⓒ None of the above. 👍 The composition, color, etc. of mixtures can vary.

🔹 Q10: 🤔 A compound can be broken down into... Ⓐ Molecules. Ⓑ 🎯 Its constituent elements. Ⓒ Other compounds. Ⓓ All of the above.

Answer: 🎯 Its constituent elements. 👍 A compound can be broken down into its constituent elements through chemical reactions.

🔹 Q11: 🤔 Elements can be broken down into... Ⓐ Molecules. Ⓑ Compounds. Ⓒ 🎯 They can't be broken down into simpler substances. Ⓓ All of the above.

Answer: Ⓒ They can't be broken down into simpler substances. 👍 An element is the simplest form of matter and cannot be broken down into anything simpler.

🔹 Q12: 🤔 Which of the following is true about mixtures? Ⓐ They are pure substances. Ⓑ They are made up of one type of particle. Ⓒ 🎯 Their composition can vary. Ⓓ Their composition is always the same.

Answer: 🎯 Their composition can vary. 👍 The composition of mixtures can vary as they are made up of two or more substances.

🔹 Q13: 🤔 A solution is an example of a... Ⓐ Compound. Ⓑ Heterogeneous mixture. Ⓒ Element. Ⓓ 🎯 Homogeneous mixture.

Answer: Ⓓ Homogeneous mixture. 👍 A solution is a homogeneous mixture as it has a uniform composition throughout.

🔹 Q14: 🤔 Sand and water form a... Ⓐ Solution. Ⓑ 🎯 Heterogeneous mixture. Ⓒ Compound. Ⓓ Element.

Answer: Ⓑ Heterogeneous mixture. 👍 Sand and water form a heterogeneous mixture as the composition is not uniform.

🔹 Q15: 🤔 The physical constants of a substance refer to its... Ⓐ Color. Ⓑ Smell. Ⓒ 🎯 Boiling point, melting point, density, etc. Ⓓ Taste.

Answer: Ⓒ Boiling point, melting point, density, etc. 👍 The physical constants of a substance, like its boiling point, melting point, and density, are properties that can be used to identify it.

🔹 Q16: 🤔 The components of a mixture can be separated by... Ⓐ Chemical reactions. Ⓑ 🎯 Physical methods. Ⓒ They can't be separated. Ⓓ Both chemical reactions and physical methods.

Answer: Ⓑ Physical methods. 👍 The components of a mixture can be separated by physical methods, like filtration or distillation.

🔹 Q17: 🤔 A compound consists of two or more... Ⓐ Compounds. Ⓑ Mixtures. Ⓒ Elements. Ⓓ 🎯 Elements chemically combined.

Answer: Ⓓ Elements chemically combined. 👍 A compound is a pure substance that is made up of two or more different elements that are chemically combined.

🔹 Q18: 🤔 In a mixture, the substances... Ⓐ Lose their original properties. Ⓑ 🎯 Retain their original properties. Ⓒ Chemically combine to form a new substance. Ⓓ Change into new substances.

Answer: Ⓑ Retain their original properties. 👍 In a mixture, the substances retain their original properties.

🔹 Q19: 🤔 In a compound, the elements... Ⓐ Retain their original properties. Ⓑ 🎯 Lose their original properties. Ⓒ Are physically combined. Ⓓ Can be separated by physical methods.

Answer: Ⓑ Lose their original properties. 👍 In a compound, the elements lose their original properties and have properties that are different from the elements that make them up.

🔹 Q20: 🤔 Elements and compounds are... Ⓐ Mixtures. Ⓑ Types of mixtures. Ⓒ 🎯 Pure substances. Ⓓ None of the above.

Answer: Ⓒ Pure substances. 👍 Elements and compounds are both pure substances, not mixtures.