The first option: the basic unit of the nervous system
The mole fraction of KBr in the solution is 0.0001
<h3>How to determine the mole of water</h3>
We'll begin by calculating the mass of the water. This can be obtained as follow:
- Volume of water = 0.4 L = 0.4 × 1000 = 400 mL
- Density of water = 1 g/mL
- Mass of water =?
Density = mass / volume
1 = Mass of water / 400
Croiss multiply
Mass of water = 1 × 400
Mass of water = 400 g
Finally, we shall determine the mole of the water
- Mass of water = 400 g
- Molar mass of water = 18.02 g/mol
- Mole of water = ?
Mole = mass / molar mass
Mole of water = 400 / 18.02
Mole of water = 22.2 moles
<h3>How to de terminethe mole of KBr</h3>
- Mass of KBr = 0.3 g
- Molar mass of KBr = 119 g/mol
- Mole of KBr = ?
Mole = mass / molar mass
Mole of KBr = 0.3 / 119
Mole of KBr = 0.0025 mole
<h3>How to determine the mole fraction of KBr</h3>
- Mole of KBr = 0.0025 mole
- Mole of water = 22.2 moles
- Total mole = 0.0025 + 22.2 = 22.2025 moles
- Mole fraction of KBr =?
Mole fraction = mole / total mole
Mole fraction of KBr = 0.0025 / 22.2025
Mole fraction of KBr = 0.0001
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Answer:

Explanation:
The symbol for TIN is Sn.
When Sn loses 2 electrons, it gets a double positive charge ( +2 ) and becomes
.
It becomes a cation.
The name of Ion is Tin ( II ) Ion.
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Hope this helped!
<h3>~AH1807</h3>
Answer:
Explanation:
The number on the top right of the symbol shows ATOMIC NUMBER , if it is written alone only one digit or number overall .
And if the number is also in bottom left then bottom left number will be ATOMIC NUMBER and top right will be MASS NUMBER
Hope this will help you *-*