Answer:
Scientists believe the batteries (if that is their correct function) were used to electroplate items such as putting a layer of one metal (gold) onto the surface of another (silver), a method still practiced in Iraq today.
Explanation:
A homogeneous mixture has the same uniform appearance and composition throughout.
A heterogeneous mixture consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.
A homogeneous mixture has the same uniform appearance and composition throughout. Many homogeneous mixtures are commonly referred to as solutions. A heterogeneous mixture consists of visibly different substances or phases.
Answer:
The periodic table is composed of seven horizontal rows or periods and is numbered between 1 and 7. There is a regular gradation in the properties of elements in the horizontal rows(periods) from left to right. The periodic table is composed of eight vertical columns or groups. They are numbered between 1 to 8.
Explanation:
The solution is buffered with a weak acid and it's conjugate base. Since NaOH is a base, you can use a weak acid as it's buffer.
Answer and Explanation:
Aspirin is odorless, but when left exposed to air in the environment, it gradually hydrolyzes into salicylic acid and acetic acid as that is the precursor for synthesizing Aspirin.
Using this hydrolyzed aspirin for titration would not be advised, because it would affect the reading of the titration. Ordinarily, apsirin is a weak acid and direct titration of aspirin is problematic because it hydrolyzes pretty fast to salicylic acid— leading to an unwanted side reaction which may or may not go to completion. Therefore, excess base must be added and heat is supplied to the mixture so that neutralization and hydrolysis are complete. The remaining base is then titrated. This is called back titration.
Now, in back titration, instead of using solution whose concentration is expected to be known, we rather use excess volume of reactant which has been left over after the completion of a reaction with the analyte.
In this case, we use an alkali, preferably NaOH (1.0 mol/dm³). Te unused NaOH remaining after the hydrolysis is titrated against a standard HCl (0.1 mol/dm³). Then from the reaction equation of the aspirin and sodium hydroxide, the amount of NaOH required for the hydrolysis can be calculated.
Answering whether the titration goes up or down, it would be observed that the titration reading would GO DOWN because the exposed aspirin used has experienced some form of hydrolysis before it was used for titration, so the hydrolysis reaction it would undergo with acetyl-salicylic acid would be minimal, and this would affect the titration reading.
But if the aspirin wasn't left exposed to the environment, the reading would go up since more hydrolysis would take place in this case.
