Extra Questions on Chemistry Chapter 2

1. What is the difference between homogeneous and heterogeneous mixtures?
- Homogeneous mixtures have uniform composition and properties throughout, while heterogeneous mixtures have non-uniform composition and properties.
- Give examples of each: Homogeneous mixture – saltwater; Heterogeneous mixture – trail mix.

2. What is the difference between an element and a compound?
- An element is a substance made up of only one type of atom, while a compound is made up of two or more different types of atoms chemically combined.
- Give examples of each: Element – oxygen; Compound – water.

3. How can you determine the number of protons, neutrons, and electrons in an atom?
- The number of protons is the atomic number, which is listed on the periodic table.
- To determine the number of neutrons, subtract the atomic number from the mass number.
- To determine the number of electrons, it depends on the ionization state of the atom.

4. What is the law of conservation of mass?
- The law of conservation of mass states that in any chemical reaction, the total mass of the reactants is equal to the total mass of the products.
- This means that atoms are neither created nor destroyed in a chemical reaction, only rearranged.

5. What is the difference between an exothermic and endothermic reaction?
- An exothermic reaction releases heat to the surroundings, while an endothermic reaction absorbs heat from the surroundings.
- Give an example of each: Exothermic – burning wood; Endothermic – melting ice.

6. What is the difference between a physical and chemical change?
- A physical change is a change in the physical properties of a substance, such as its shape, size, or state of matter, without changing its chemical composition.
- A chemical change is a change in the chemical composition of a substance, resulting in the formation of a new substance.
- Give examples of each: Physical change – melting ice; Chemical change – burning wood.

By understanding the concepts presented in these questions, students can deepen their understanding of chemistry fundamentals.

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