Answer:D
Explanation:I just took it
Start by looking to the product there that doesn't have coefficient. Need to have exactly 2 Fe on the reactant side. So first coefficient is 2.. having a 2 there gives 2*3 = 6 H on the reactant side. Then in order to have 6 H on the product side the coefficient there needs to be 3. This gives 3 Ca on product side so there must be 3 Ca on reactant side.
coefficients:
2 + 3 --> 1 + 3
<span>To find the percent yield, we first need to write this out as an equation:
3A + 2B --> C + 6D. The moles of C equals 1/3 times the moles of A. Therefore, the moles of C equals 4/3.
The theoretical yield equals = moles x molar mass of C.
(4/3) x (310.2) = 413.6g
The percent yield equals actual yield/theoretical yield x 100%.
382.5g/413.6g x 100% = 92.48%</span>
Answer:
1.58x10⁻⁵
2.51x10⁻⁸
0.0126
63.10
Explanation:
Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:
pH = pKa + log[In-]/[HIn]
pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,
i) pH = 4.9
4.9 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = - 4.8
[In-]/[HIn] =
[In-]/[HIn] = 1.58x10⁻⁵
ii) pH = 2.1
2.1 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = -7.6
[In-]/[HIn] =
[In-]/[HIn] = 2.51x10⁻⁸
iii) pH = 7.8
7.8 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = -1.9
[In-]/[HIn] =
[In-]/[HIn] = 0.0126
iv) pH = 11.5
11.5 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = 1.8
[In-]/[HIn] =
[In-]/[HIn] = 63.10
The answers are low concentrated (dilute) and high concentrated respectively.
As the low concentrated salt solution has a higher water potential than that of the high concentrated salt solution, water molecules will flow from the region of higher water potential to the region of lower water potential, thus from the dilute salt solution to the high concentrated salt solution. This is due to the movement called osmosis. Note that osmosis also requires water to flow through a differentially permeable membrane, which means the membrane can allow certain substances (not all) to go in or out. If the differentially permeable membrane is not present, the movement of water molecules may be regarded as diffusion.
Therefore, the answers for the blanks are low concentrated and high concentrated.