Answer: Option B
Explanation:
Cell membrane can be defined as the outermost covering of the cell which allows the movement of particles across membrane. The particles are allowed to move from inside of the cell to the outside of the cell and from outside to inside of the cell.
This kind of a membrane is known as selectively permeable which allows the movement of certain molecules only.
hence, the correct answer is option B
Answer:
1. 77.5g,
2. 1.78 mol,
3. 281 g
4. add 80 mL of water
Explanation:
1. Molar mass (Na2O) = 2*23.0 + 16.0 = 62.0 g/mol
1.25 mol *62.0 g/1mol = 77.5 g Na2O
2. Molar mass (KOH) = 39.1 +16.0+1.0 = 56.1 g/mol
100 g * 1 mol/56.1 g = 1.78 mol KOH
3. Molar mass (KOH) = 39.1 +16.0+1.0 = 56.1 g/mol
5 mol * 56.1g/1 mol = 281 g KOH
4. M1V1 =M2V2
M - molarity, V- volume of solution
2.0M*20mL = 0.4M*V2
V2 = 2.0*20/0.4 = 100 mL
Volume of diluted solution = 100 mL
We have 20 mL of solution, we need 100 mL of solution,
so we need to add (100-20) =80mL of water.
Take 20 ml 2.0 Molar of solution of HCl , add 80 mL of water, then we get 100 mL 0.4 M solution of HCl.
No boiling water is not a chemical change it would be a physical change
