Achemist needs to determine the concentration of a solution of nitric acid, hno3. she puts 875 ml of the acid in a flask along with a few drops of indicator. she then slowly adds 0.800 m ba(oh)2 to the flask until the solution turns pink, indicating the equivalence point of the titration. she notes that 285 ml of ba(oh)2 was needed to reach the equivalence point. solution map in this titration, the concentration of base is known and can be used to calculate the unknown acid concentration: concentration of base ⟶ moles of base ⟶ moles of acid ⟶ concentration of acid part a how many moles of ba(oh)2 are present in 285 ml of 0.800 m ba(oh)2?

There are 0.288 moles of Ba(OH)₂ in 285 mL of 0.800 M Ba(OH)₂

Explanation:

The specific question is how many moles of Ba(OH)₂ are present in 285 mL of 0.800 M Ba(OH)₂.

In a titration, the determination of the number of moles of the substance whose molarity is known, is the first step of the calculations.

Since you know the molar concentration, and the volume of the substance, in this case the base Ba(OH)₂, you can use the molarity formula to solve for the number of moles:

The name of the variables are:

M = molarityn = number of moles of solute (Ba(OH)₂ in this case)V = volume in liters of the solution

Formula:

M = n / V (in liters) [this is the definition of molarity]

Solve for n:

n = M × V

Substitute the known values>

n = 0.285 liter × 0.800 M = 0.228 mole keep the 3 significant figures

0.288 moles of Ba(OH)₂.

Note that from the number of moles of one component (the base, in this case), you can calculate the molar concentration of the other component (the acid in this case),  because, at the equivalence point, both acid and base reactants are at the theoretical mole ratio, i.e. both are consumed.

D.na is the answer hope this

The answer to your question really depends on three things: how much water you have, how cold it is to start out, and how cold the things around it are. water actually freezes when it gets to 32 degrees fahrenheit (0 degrees celsius), but the time it takes to get there may be different.  let's start with the first. if you take two glasses, and fill one with a tiny bit of water, and the other about halfway, then put them both in the freezer, the one with less water will freeze first (you can try this at home, but i recommend using plastic cups and not glass ones).  now let's move on to the second part. let's say you have two glasses, and you fill one with really cold water that has been in the refrigerator, and the other with really hot water from the sink. if you put both of them in the freezer, the one that started out colder will freeze first.  for the third part, let's imagine that you have two glasses with the same amount of water in them, and the water is at the same temperature. imagine putting one outside on a really really cold day in georgia, and having a friend in alaska put one outside on the same day. since it would be so much colder in alaska, the glass of water there would freeze before yours.  so, if you took a tiny bit of really cold water in a glass, and put it outside on a cold day in alaska, it would freeze a lot faster than a big glass of hot water outside on a cold day in georgia.