Answer: 
is a reactant; it is present before the reaction occurs.
Explanation:
In a chemical reaction the chemical formulas written before the arrow are described as reactants as they react together to form products which are written after the arrow.
Thus and HCl are reactants here whereas 
, 
and 
are products.
Answer:
3.43×10¹ mol
Explanation:
Given data:
Initial number of moles = 12.4 mol
Initial volume = 122.8 L
Final number of moles = ?
Final volume = 339.2 L
Solution:
The number of moles and volume are directly proportional to each other at same temperature and pressure.
V₁/n₁ = V₂/n₂
122.8 L/ 12.4 mol = 339.2 L / n₂
n₂ = 339.2 L× 12.4 mol / 122.8 L
n₂ = 4206.08 L.mol /122.8 L
n₂ = 34.3mol
In scientific notation:
3.43×10¹ mol
Pressure has no effect on the solubility of KNO3 in water. This is because it is solid in liquid type of solution. In solid in liquid type of solution, solid is solute (minor component), liquid is solvent (major component). For solid in liquid type of solutions, solubility is independent of pressure.
On other hand, pressure has a pronounced effect on the solubility of gas in liquid type solutions. In such system, gas is solute (minor component) and liquid is solvent (major component). Example of such solution is aerated water. Herein, CO2 is dissolved in water. In such gas in liquid type of solutions, solubility increases with increasing pressure.
Your answer is 1-3-2-4 , grass sand water rock
