Salt dissolves more quickly in water when the water molecules are moving very quickly. in which of these water samples would salt dissolve most slowly?

I believe the answer is A. 15 degrees Celsius.

So, If salt dissolves faster when molecules moves very fast, We add kinetic energy. When we add Kinetic energy to water, we make the water get hotter, which causes the molecules in the water to move faster.

So, if the water is hotter the salt will dissolve faster!

15 degrees Celsius translates to 59 degrees Fahrenheit. Anything number bigger than 15 degrees will dissolve quicker than 15. 98 degrees Celsius is much hotter than 15 degrees Celsius, so I don't understand how anyone would get that answer.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2