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 diagram of dots na₂ + o₂ diagram of dots and circles ag diagram of dots

Explanation:

1. Elements are pure substances that cannot be broken down chemically, while compounds are pure substances that can be broken down chemically.
2. Carbon is the element found in all organic compounds.
3. The Earth's atmosphere is a mixture of different gases like nitrogen, oxygen, carbon - dioxide etc.
4. A compound is made up of two or more different elements chemically combined. $H_2O$ is a compound of hydrogen and oxygen. $Si$ and $Zn$ are elements, and $C + O_2$ is a chemical reaction.
5. Compounds can only be broken down by chemical means, not physical means.
6. A homogeneous mixture has a uniform composition and the same properties throughout.
7. Compounds have different properties than the elements that make them up due to chemical bonding.
8. Chemical reactions are used to break the bonds in a compound.
9. $HCl$ is a compound as it is made of hydrogen and chlorine chemically bonded. The second diagram (just dots) could represent an element if all dots are of the same type. $Na_2+O_2$ is a mixture of sodium and oxygen. The fourth diagram with different - sized and colored dots could be a mixture. $Ag$ is an element. The last diagram with molecules 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; Second diagram - Element (if all dots same type); $Na_2 + O_2$ - Mixture; Fourth diagram - Mixture; $Ag$ - Element; Last diagram - Compound