Answer:
number of moles of water (n) = 1.383 x10 ⁻⁵ mol
Explanation:
Data Given:
No. of molecules of water = 8.33×10¹⁸
No. of Mole of water = ?
Formula Used to calculate
no. of moles = numbers of particles (ions, molecules, atoms) /Avogadro's number
Avogadro's no. = 6.023 x10²³
So the formula could be written as
no. of moles (n) = no. of molecules of water /6.023 x10²³
Put the values in above formula
no. of moles (n) = 8.33×10¹⁸ /6.023 x10²³
no. of moles (n) = 8.33×10¹⁸ /6.023 x10²³
no. of moles (n) = 1.383 x10 ⁻⁵
so 1.383 x10 ⁻⁵ moles of water are represented by 8.33×10¹⁸ molecules of water.
Should be 2Na + Br2 = 2NaBr :)
Answer:
ΔH = 2.68kJ/mol
Explanation:
The ΔH of dissolution of a reaction is defined as the heat produced per mole of reaction. We have 3.15 moles of the solid, to find the heat produced we need to use the equation:
q = m*S*ΔT
<em>Where q is heat of reaction in J,</em>
<em>m is the mass of the solution in g,</em>
<em>S is specific heat of the solution = 4.184J/g°C</em>
<em>ΔT is change in temperature = 11.21°C</em>
The mass of the solution is obtained from the volume and the density as follows:
150.0mL * (1.20g/mL) = 180.0g
Replacing:
q = 180.0g*4.184J/g°C*11.21°C
q = 8442J
q = 8.44kJ when 3.15 moles of the solid react.
The ΔH of the reaction is:
8.44kJ/3.15 mol
= 2.68kJ/mol
Galvanizing protects from rust in a number of ways: It forms a barrier that prevents corrosive substances from reaching the underlying steel or iron. The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.
