Answer: Temperature and number of moles are the conditions which remain constant in Boyle's law.
Explanation:
Boyle's law states that at constant temperature the pressure of a gas is inversely proportional to the volume of gas.
Mathematically, it is represented as follows.
As equation for ideal gas is as follows.
PV = nRT
And, at constant temperature the pressure is inversely proportional to volume which also means that number of moles are also constant in Boyle's law.
Thus, we can conclude that temperature and number of moles are the conditions which remain constant in Boyle's law.
Molar mass of LiBr ( lithium bromide ) = <span>86.845 g/mol
</span><span>Amount of calculation to moles of lithium bromide (LiBr)
86.845 g ------------- 1 mole
100 g ----------------- ?
n = m / M
n = 100 / 86.845
n = 1.1514 moles of LiBr
V ---------------------1.1514 moles
1 L -------------------- 4 M
1.1514 * 1 / 4
V = 1151.4 / 4
V = 0,28785 L
hope this helps!
hope this helps !</span>
Answer:
Blue vitriol is crystal copper sulphate
Explanation:
The black oxide is the higher oxide of Copper i.e Cu. It is also called as tenorite. It is solid black in color. It is formed by heating copper with air.

Blue vitriol is the crystalline form of copper sulphate. It is also known as copper (II) sulphate.
When heating, the blue vitriol undergoes various steps of changes to the black oxide of copper.
The chemical reaction is --

Explanation:
The given data is as follows.
Concentration of acid, [HF] = 2 M
Concentration of salt, [NaF] = 0.472 M
Concentration of base, [NaOH] = 1.00 M
= 
So, NaOH being a base will react with the acid that is, HF. And, according to Henderson-Hasselbalch equation we have he following.
pH = ![pK_{a} + log\frac{[salt]}{[acid]}](https://tex.z-dn.net/?f=pK_%7Ba%7D%20%2B%20log%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bacid%5D%7D)
Also, we known that 
so, 
= 3.1426
Hence, pH = 
pH = 2.5155
Thus, we can conclude that pH of the solution is 2.5155.