The concentration of a substance is the quantity of solute present in a given quantity of solution.
Two electrons are needed to complete hydrogen's outer shell.
Answer:
Solid state : In this state, the molecules are arranged in regular and repeating pattern. The molecules are closely packed that means they are fixed and vibrate in place but they can not move from one place to another. They have least kinetic energy. For example : chair
Liquid state : In this state, the molecules are present in random and irregular pattern. The molecules are closely packed but they can move from one place to another. They have more kinetic energy than solids but less than that of gases. For example : oil
Gaseous state : In this state, the molecules are present in irregular pattern. The molecules are not closely packed and they can move freely from one place to another and spread out. They have most kinetic energy. For example : Hydrogen
I think the symbol of the element is Ga sorry if I’m wrong
Answer:
The enthalpy change for the reaction is ΔH = - 54.3 kJ/mol
Explanation:
The reaction between HCl and NaOH is a neutralization reaction:

Heat released during neutralization = Heat gained by water
i.e. 
where:

m = total mass of solution

ΔT = change in temperature = 22.8 - 21.5 = 1.3 C
c = specific heat = 4.18 J/g C

As per equation (1): qrxn = -434.7 J
The reaction enthalpy ΔH is the heat released per mole of acid (or base)

