Answer:
Decreases
Explanation:
An element's oxidation number decreases because it gained electrons.
Answer: The molar enthalpy change is 73.04 kJ/mol
Explanation:

moles of HCl= 
As NaOH is in excess 0.0415 moles of HCl reacts with 0.0415 moles of NaOH.
volume of water = 100.0 ml + 50.0 ml = 150.0 ml
density of water = 1.0 g/ml
mass of water = 

q = heat released
m = mass = 150.0 g
c = specific heat = 
= change in temperature = 


Thus 0.0415 mol of HCl produces heat = 3031.3 J
1 mol of HCL produces heat = 
Thus molar enthalpy change is 73.04 kJ/mol
A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds. Elements: are pure substances made up of only l type of atom. Atoms of the same element are identical in properties.
❌formed by 2 ions
❌ionic bonds
✅yes because of solvation
✅yes electrolytes are substances that break apart into ions when dissolved
✅in itself but salt water is a good conductor
✅such as water