Answer: A. Limestone rocks dissolving in water
Explanation:
B: This is a physical change; it changes an object physically rather than chemically. It does not change the composition of the concrete, only the shape.
C: This is also a physical change because the water is just dragging sand with it, but not actually changing the composition of it.
D: Similar to option B, this is an example of physical weathering because the ice only divides the rock into different parts but doesn't change the composition or complexity of it.
It’s C.valley formed from water erosion
The classification of living things makes it easier for scientists to answer many important questions.
Examples:
-How many known species are there?
-What are the defining characteristics of each species?
-What are the relationships between these species?
Answer:
The nucleus represents a major evolutionary transition. As a consequence of separating translation from transcription many new functions arose, which likely contributed to the remarkable success of eukaryotic cells. Here we will consider what has recently emerged on the evolutionary histories of several key aspects of nuclear biology; the nuclear pore complex, the lamina, centrosomes and evidence for prokaryotic origins of relevant players.
The amount of oxygen that are produced when 1.06 grams of potassium chlorate decompose completely is 0.64 grams.
<h3>What is the relation between mass & moles?</h3>
Relation between the mass and moles of any substance will be represented as:
- n = W/M, where
- W = given mass
- M = molar mass
Moles of potassium chlorate = 1.66g / 122.5g/mol = 0.0135mole
Given chemical reaction is:
2KClO₃ → 2KCl + 3O₂
From the stoichiometry of the reaction, it is clear that:
2 moles of KClO₃ = produces 3 moles of O₂
0.0135 moles of KClO₃ = produces (3/2)(0.0135)=0.02 moles of O₂
Mass of oxygen = (0.02mol)(32g/mol) = 0.64 g
Hence produced mass of oxygen is 0.64 grams.
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