This is a question in Seneca, plz help asap bc I can't skip it!! What do we call a pure sample that's run next to the tested substance to see if it's a component in the mixture?

Using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 pb+2(aq) + 2cl -(aq). if the value of ksp was determined to be only 1.2 x 10-2: too much solid has dissolved. additional precipitate is forming. the solution is unsaturated. the ions are now combining to reduce their concentrations.

In france, grapes are 1.95 euros per kilogram. what is the cost of grapes, in dollars per pound, if the exchange rate is 1.14 dollars/euro? (2.6)

What is the compound name for the formula [ru(en)2cl2]2+ and [co(en)cl2br]-