Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions. Example : Reaction of iron nails with copper sulphate solution.
Answer:
The order in which the orbitals is filled is 1s-2s-2p-3s-3p-4s-3d-4p-5s-4d-5p-6s-4f-5d-6p-7s-5f-6d-7p
Explanation:
S orbitals each hold two electrons, p orbitals hold 6, d orbitals hold 10, and f orbitals hold 14. 1s has the least energy and 7 p has the greatest energy, so the order in which they are filled is listed above.
Given parameters:
Heat of fusion of water = 334j/g
Mass of ice = 45g
Temperature of ice = 0.0°c
Unknown:
Amount of heat needed to melt = ?
Solution:
This is simply a phase change and a latent heat is required in this process.
To solve this problem; use the mathematical expression below;
H = mL
where m is the mass
L is the heat of fusion of water;
H = 45 x 334 = 15030J
Answer:
1.373 wt% Ca(OH)₂
Explanation:
Sample mix = 15.0g
Ca(OH)₂(aq) + 2HCl(aq) => CaCl₂(aq) + 2H₂O(l)
moles HCl = 0.2000g / 36 g·mol⁻¹ 0.0056 mol
moles Ca(OH)₂ = 1/2(moles HCl) = 1/2(0.0056 mol) = 0.0028 mol
mass Ca(OH)₂ = 0.0028 mol ( 74 g/mol ) = 0.206 g
mass % Ca(OH)₂ = (0.206/15.0)100% = 1.373 wt%
