Answer:
Length
- centimetre
- millimetre
- kilometre
- meter
Mass
- gram
- kilogram
Capacity
- liter
- millilitre
I don't know why mass is there but hope this helps! :)
The enthalpy change : -196.2 kJ/mol
<h3>Further explanation </h3>
The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation
The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The value of ° H ° can be calculated from the change in enthalpy of standard formation:
∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)
Reaction
2 H₂O₂(l)-→ 2 H₂O(l) + O₂(g)
∆H ° rxn = 2. ∆Hf ° H₂O - 2. ∆Hf °H₂O₂

Answer:
As you move from left to right, the nucleus gains protons. This increases the positive charge of the nucleus and its attractive force on the electrons. At the same time, electrons are added to the atoms as you move from left to right across a period.
Explanation:
A covalent bond? Not sure how much detail you want, sorry