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lorasvet [3.4K]
3 years ago
9

Which best describes the act of using senses or tools to gather information? creating a hypothesis making an observation summari

zing the results recording the measurements
Chemistry
1 answer:
MAXImum [283]3 years ago
3 0

Answer:

making an observation

Explanation:

its the right answer

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A rigid, closed vessel of volume V =648 liters maintained at constant temperature T=365 K is loaded with 112 mol of n-hexane, 15
Marrrta [24]

Answer:

P = 2.92 atm

Explanation:

With the three assumptions in mind, the system consists of:

  • A liquid phase containing n-hexane and n-heptane, and
  • A gaseous phase containing n-hexane vapor, n-heptane vapor, and nitrogen gas.

First we use PV=nRT to calculate the moles of n-hexane and n-heptane in the gaseous phase:

  • n-hexane:

P = 0.199 MPa ⇒ 0.199 * 1.869 = 1.964 atm

  • 1.964 atm * 648 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 365 K
  • n = 42.52 moles
  • n-heptane:

P = 0.083 MPa ⇒ 0.083 * 1.869 = 0.155 atm

  • 0.155 atm * 648 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 365 K
  • n = 3.358 moles

So <u>the gaseous phase consists of 42.52 moles of n-hexane, 3.358 moles of n-heptane, and 14 mol of nitrogen</u>.

For the liquid phase, we <u>calculate the remaining moles of n-hexane and n-heptane</u>. Then we<u> convert to liters</u>, using their molar volumes:

  • n-hexane:
  • n = 112 mol - 42.52 mol = 69.48 mol
  • 69.48 mol * 0.146 L/mol = 10.14 L
  • n-heptane:
  • n = 155 mol - 3.358 mol = 151.642 mol
  • 151.642 mol * 0.162 L/mol = 24.57 L

So the liquid phase occupies (10.14+24.57) = 34.71 L, and <u>contains 69.48 mol of n-hexane and 151.64 mol of n-heptane</u>.

Finally, to<u> calculate the pressure in the vessel</u>, we use PV=nRT:

P = ?

V = 648 - 34.71 = 613.29 L

n = 42.52 mol hexane + 3.35 mol heptane + 14 mol nitrogen = 59.87 mol

T = 365 K

  • P * 613.29 L = 59.87 mol *  0.082 atm·L·mol⁻¹·K⁻¹ * 365 K
  • P = 2.92 atm
6 0
3 years ago
From the Henderson-Hasselbalch equation, explain how the ratio [Al/[HA] changes with changing pH
Kryger [21]

Answer:

The ratio [A-]/[HA] increase when the pH increase and the ratio decrease when the pH decrease.

Explanation:

Every weak acid or base is at equilibrium with its conjugate base or acid respectively when it is dissolved in water.

HA + H_{2}O ⇄ A^{-} + H_{3}O^{+}

This equilibrium depends on the molecule and it acidic constant (Ka). The Henderson-Hasselbalch equation,

pH = pKa + Log \frac{[A^{-}]}{[HA]}

shows the dependency between the pH of the solution, the pKa and the concentration of the species. If the pH decreases the concentration of protons will increase and the ratio between A- and AH will decrease. Instead, if the pH increases the concentration of protons will decreases and the ratio between A- and AH will increase.

5 0
3 years ago
How many grams of iron are needed to produce 75.0 g of iron(III) chloride?
OleMash [197]

Answer:

Explanation:

Hello!

In this case, given the chemical reaction:

In such a way, given the volumes and molarities of each reactant, we can compute the moles of produced iron (III) hydroxide by each of them, via the 3:1 and 1:1 mole ratios:

It means that the sodium hydroxide is the limiting reactant and 0.00833 moles of iron (III) hydroxide are produced; thus, the required mass is:

8 0
3 years ago
Which sample of ethanol has particles with the highest average kinetic energy?
ale4655 [162]
The second one.
Remember, temperature is the AVERAGE kinetic energy. So, looking for highest average kinetic energy means looking for highest temperature, which is 55.
Note: the amount of the substance does not determine the average kinetic energy. 
6 0
3 years ago
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What did Ernest Rutherford s gold foil experiment demonstrate about atoms?
Ghella [55]
-Positively charged nucleus 
-Empty spaced
-Dense core
5 0
3 years ago
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