The nucleus of a comet is made up of rock, dust, and frozen gasses
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Answer:
The solution would need 13.9 g of KCl
Explanation:
0.75 m, means molal concentration
0.75 moles in 1 kg of solvent.
Let's think as an aqueous solution.
250 mL = 250 g, cause water density (1g/mL)
1000 g have 0.75 moles of solute
250 g will have (0.75 . 250)/1000 = 0.1875 moles of KCl
Let's convert that moles in mass (mol . molar mass)
0.1875 m . 74.55 g/m = 13.9 g
Answer:
This means that the isotope of silicon with a mass number of 28 is by far the most common of these three isotopes.
Explanation:
The abundance of Si-28 is 92.23%. Si-29 is 4.68% and Si-30 is 3.09%.
Because most Si atoms have a mass of 28 amu, the average mass of all silicon atoms is very close to 28.
Here is a video which summarizes how to calculate average atomic mass from data about mass and relative abundance.
Answer
B. acid + base --> salt + water
Explanation
Acids are substances that dissolve in water to produce hydrogen ions, H+.A base is a substance that dissolves in water to produce hydroxide ions, OH-.In a chemical reaction of an acid and a base, the products are a salt and water.For example when hydrocholoric acid is added to sodium hydroxide, a salt namely sodium chloride is formed with additional water.