Answer:
x² = mutiphy by them self
Explanation:
<u>Answer:</u> The mass of sodium chloride solution present is 0.256 grams.
<u>Explanation:</u>
We are given:
39.0 % of sodium in sodium chloride solution
This means that 39.0 grams of sodium is present in 100 grams of sodium chloride solution
Mass of sodium given = 100 mg = 0.1 g (Conversion factor: 1 g = 1000 mg)
Applying unitary method:
If 39 grams of sodium metal is present in 100 grams of sodium chloride solution
So, if 0.1 grams of sodium metal will be present in = 
of sodium chloride solution.
Hence, the mass of sodium chloride solution present is 0.256 grams.
Answer:
False
Explanation:
False. The molecules of liquid are hold in the liquid state due to intermolecular forces or Van de Waals forces , without affecting the molecule itself and its atomic bonds (covalent bonds). When the temperature increases the kinetic energy of the molecules is higher , therefore they have more possibilities to escape from the attractive intermolecular forces and go to the gas state.
Note however that this is caused because the intermolecular forces are really weak compared to covalent bonds, therefore is easier to break the first one first and go to the gas state before any covalent bond breaks ( if it happens).
A temperature increase can increase vaporisation rate if any reaction is triggered that decomposes the liquid into more volatile compounds , but nevertheless, this effect is generally insignificant compared with the effect that temperature has in vaporisation due to Van der Waals forces.
Answer:
Small holes in plants that allow carbon dioxide in and oxygen and water vapor out
Explanation:
Stomata are tiny holes that open and close for the plant to breathe.
Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
