Chemistry questions Urgent!!!

1. which two solutions, when mixed together, will undergo a doublereplacement reaction and form a white, solid substance?


b) KCl (aq) and AgNO3 (aq)

AgNO3(aq) + KCl (aq) → AgCl (s) + KNO3(aq)
AgCl forms a white precipitate

KNO3 is quite soluble in water. AgCl forms a white precipitate in water.


2.student wants to prepare a 1L solution of a specific molarity. thestudent determines that the mass of the solute needs to be 30g. what isthe proper procedure to follow?

d. add enough solvent to 30g of solute to make 1L of solution

This is a concept that confuses students. Molarity is the number of moles of solute dissolved in one liter of solution. What this means is that you have x number of mole of a solute in a 1L solution.

The solution concetration is always given in terms of the form of the solute BEFORE it dissolves.

For example, when a solution is described as being 1.0M NaCl, this means that the solution is prepared by dissolving 1.0 mole of solid NaCl in enough water to make 1.0L of solution. It does not mean adding 1.0 mole of NaCl to a 1.0L of solvent.

In your question above, you first take 30g of solute and then add enough solvent to it to make a 1L solution. The other answers are wrong since (a) & (c) will create over 1L of solution and (b) is wrong because you cannot be certain that 30g of this unknown chemical occupy 30mL in a solution.