Question

1. which of the following indicates that a physical change has taken place? a. gas production b. energy transfer c. fracture formation d. precipitate formation 21. a lava - flow is a type of a. sill. b. dike. c. intrusion. d. extrusion. 22. what does “2” mean in the formula for water, h₂o? a. two molecules of hydrogen b. two molecules of water c. two atoms of oxygen d. two atoms of hydrogen 23. the hardest mineral on the mohs hardness scale is a. talc. b. diamond. c. gypsum. d. fluorite. 24. the series of changes that describes how geologic forces cause rock to change from one type to another is known as a. bowen’s reaction series. b. mohs hardness scale. c. fractional crystallization. d. the rock cycle. 25. what happens to matter during a chemical reaction? a. some matter is destroyed. b. some matter is created. c. matter is neither destroyed or created. d. some matter is destroyed and some is created. 26. where are electrons found in atoms? a. in the atomic ring cycle b. in the electron cloud c. in the electron sphere d. in the electron zone 27. which of the following is not a sedimentary rock feature? a. stratification b. delta c. mud crack d. ripple mark

Explanation:

• Question 20: Gas production, energy transfer, and precipitate formation can be signs of chemical changes. Fracture formation is a physical change as it only changes the physical appearance without altering the substance's chemical composition.
• Question 21: A lava - flow is an extrusion as it is magma that reaches the Earth's surface. Sills and dikes are intrusions (forms of igneous rock that form within the Earth's crust).
• Question 22: In the formula $H_2O$, the "2" represents two atoms of hydrogen.
• Question 23: Diamond is the hardest mineral on the Mohs hardness scale. Talc is the softest (1 on the scale), gypsum is 2, and fluorite is 4.
• Question 24: The rock cycle describes how geologic forces cause rock to change from one type to another. Bowen's reaction series is about the crystallization of magma, and the Mohs hardness scale is for mineral hardness.
• Question 25: According to the law of conservation of mass, matter is neither destroyed nor created during a chemical reaction.
• Question 26: Electrons are found in the electron cloud around the nucleus of an atom.
• Question 27: Stratification, delta, and ripple mark are features of sedimentary rocks. Mud cracks are not exclusive to sedimentary rocks and are not a typical sedimentary - rock feature in the same sense as the others.

Answer:

• Question 20: c. fracture formation
• Question 21: d. extrusion
• Question 22: d. two atoms of hydrogen
• Question 23: b. diamond
• Question 24: d. the rock cycle
• Question 25: c. Matter is neither destroyed or created.
• Question 26: b. in the electron cloud
• Question 27: c. mud crack