Ceres is a dwarf planet, so A.
Answer:
0.02405 g/L is the solubility of argon in water at 25 °C.
Explanation:
Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.
To calculate the molar solubility, we use the equation given by Henry's law, which is:

where,
= Henry's constant = 
= partial pressure of carbonated drink = 0.51atm
Putting values in above equation, we get:

Molar mass of argon = 39.95 g/mol
Solubility of the argon gas :

0.02405 g/L is the solubility of argon in water at 25 °C.
Answer: 2
Explanation:
To calculate the moles :

According to stoichiometry :
1 mole of
are produced by = 4 moles of 
Thus 1.18 moles of
will be produced by=
of 
Mass of 
Thus 85.0 g of
will be required and 2 steps are required to get the answer.
To calculate the pKa of the weak acid, we use the Henderson-Hasselbalch equation. It is expressed as pH = pKa - log [HA]/[A-]. This equation takes into account the concentration of the substance that does not dissociates into ions since it is a weak acid. We caculate as follows:
pH = pKa - log [HA]/[A-]
9 = pKa - log 1/100
pKa = 7