Question

1. how are elements and compounds different? a. elements are many different types of atoms together but compounds are just one type of atom b. elements are pure substances that cannot be broken down physically but compounds are pure substances that can be broken down physically. c. elements are not found on the periodic table but compounds are found on the periodic table. d. elements are pure substances that cannot be broken down chemically but compounds are pure substances that can be broken down chemically. 2. which element is found in all organic compounds? a. mercury (hg) b. oxygen (o) c. potassium (k) d. carbon (c) 3. the atmosphere that covers our planet is considered a(n) – a. element b. compound c. mixture d. organic compound 4. which of the following could be the chemical formula for a compound? a. si b. h₂o c. zn d. c + o₂ 5. true or false: compounds can only be broken down by chemical means. a. true b. false 6. a ____________ mixture has a uniform composition and the same properties throughout. 7. compounds have __________ properties than the elements that make them up. 8. the only way to break the bonds in a compound is with a ____________. 9. examine the diagrams below and then label each one as either an element, compound, or mixture. hcl na₂ + o₂ ag

Explanation:

1. Elements are pure substances that cannot be broken down chemically, while compounds are pure substances that can be broken down chemically into elements.
2. Carbon is the key element in all organic compounds.
3. The atmosphere is a mixture of different gases like nitrogen, oxygen, carbon - dioxide etc.
4. A compound is made of two or more different elements chemically combined. $H_2O$ is a compound of hydrogen and oxygen.
5. Compounds can only be broken down by chemical means, not physical ones.
6. A homogeneous mixture has a uniform composition throughout.
7. Compounds have different properties from the elements that compose them due to chemical bonding.
8. Chemical reactions are required to break the bonds in a compound.
9. $HCl$ is a compound as it is made of hydrogen and chlorine chemically combined. The diagram of single - type dots is an element. $Na_2+O_2$ is a mixture as it shows two separate substances not chemically combined. The diagram with different types of non - bonded particles is a mixture. $Ag$ (silver) is an element. The diagram with bonded particles of the same type is a compound.

Answer:

1. D. Elements are pure substances that cannot be broken down chemically but compounds are pure substances that can be broken down chemically.
2. D. Carbon (C)
3. C. Mixture
4. B. $H_2O$
5. A. True
6. homogeneous
7. different
8. chemical reaction
9. $HCl$: compound; Diagram of single - type dots: element; $Na_2 + O_2$: mixture; Diagram with different non - bonded particles: mixture; $Ag$: element; Diagram with bonded particles of the same type: compound