The wording makes this question difficult, but HCl is found in stomach acid. Hope this helps!
Answer:
The boiling point decreases as the volume decreases.
Explanation:
The Temperature - Volume law otherwise called as Charles law is applied, which says that the volume of the given gas at constant pressure is directly proportional to the temperature measured in Kelvin. As the volume increases, the temperature also increases, if the volume decreases, then the temperature also decreases.
As per the Charles law, here the volume is decreased from 50 ml to 25 ml so the boiling point also decreases.
Answer:

Explanation:
Given the amount of heat absorbed and the amount of substance in moles, we may calculate the heat of vaporization. Heat of vaporization is defined as the amount of heat per 1 mole of substance required to evaporate that specific substance.
Based on the value of heat of vaporization, we will identify the substance. Firstly, let's calculate the heat of vaporization:

Secondly, let's use any table for heat of vaporization values for substances. We identify that the heat of vaporization of
is 18.7 kJ/mol
Answer:
1.244x10^23 molecules
Explanation:
From Avogadro's hypothesis, 1mole of any substance contains 6.02x10^23 molecules.
This means that 1mole of SiO2 contains 6.02x10^23 molecules
1mole of SiO2 = 28 + (2x16) =28 +32 = 60g
If 1 mole(i.e 60) of SiO2 contains 6.02x10^23 molecules,
Therefore, 12.40g of SiO2 will contain = (12.40 x 6.02x10^23) / 60 = 1.244x10^23 molecules