Answer:
The solution is not ideal and shows a positive deviation from Raoult’s law since Psolution (experimental) > Psolution (actual).
Explanation:
Number of moles of CS2 = 3.95g/76.13gmol-1 = 0.0519 moles
Number of moles of acetone = 2.43g/58.08gmol-1 = 0.0418 moles
Total number of moles = 0.0937 moles
Mole fraction of CS2 = 0.0519/0.0937 = 0.5538
Mole fraction of acetone = 0.0418/0.0937 = 0.4461
From Raoult’s law;
PCS2 = 0.5538 × 515 torr = 285.207 torr
Pacetone = 0.4461 × 332 torr = 148.1052 torr
Total pressure = 285.207 torr + 148.1052 torr = 433.3 torr
The percent by mass of potassium in K3Fe(CN)6 is 35.62%.
The concept used here is the Law of Conservation of Mass. Technically, it's more specifically included in the Law of Definite Proportions. According to Dalton's atomic theory, when substances react together, they form a compound that has the same fixed ratio of the individual elements. That is the main reason why we balance, because stoichiometric coefficients are essential to obey the Law.
For the reaction a + b ⇒ ab, this is a combination reaction. For every 1 mole of a and 1 mole of b, 1 mole of product ab is formed. This is the fixed ratio we have to follow: 1:1:1. Now, the next thing to note is the limiting and excess reactant. If initially, there are 2 moles of A and 3 moles of B, the limiting reactant is A and the excess is B. Since the ratio between reactants is 1:1, 3 moles of B requires 3 moles of A. But since only 2 moles are available, reactant A is limited. In this problem, we assume that B is provided in excess. So, we just focus on the amount of the limiting reactant a.
If there are 5,000 molecules of a, we can determine the molecules of ab using the fixed ratio, 1 part a is to 1 part ab. Then, that means that 5,000 molecules of a would yield also 5,000 molecules of ab.
Answer:
Explanation:
When converting from moles to atoms, we must use Avogadro's number. This number tells us there are 6.022 * 10²³ atoms in 1 mole. We can multiply this number by the number of moles.
First, we must set up Avogadro's number as a ratio.
Next, multiply the number of moles by the ratio.
When we multiply, the moles of silicon will cancel.
Since the denominator of the fraction is 1, we can cancel it out too.
The original measurement (2.5 moles) has 2 significant figures (2 and 5). Therefore we must round to 2 sig figs. For this question, 2 sig figs is the tenth place.
The 0 in the hundredth place tells us to leave the 5 in the tenth place.
There are about <u>1.5 * 10²⁴ atoms of silicon.</u>
15.999 is the mass of oxygen
