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3 years ago

A balloon moves vertically upward at

Chemistry

1 answer:

Usimov [2.4K]3 years ago

6 0

Answer:

B. Velocity

Explanation:

The answer is Velocity because the def of velocity is the rate of constant speed in a given direction. I hope this helps, have a good night.

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The pka of hf is 3.2 determine the pkb of hf?

Julli [10]

Well, first we must remember that

$pK_{a}+pK_{b}=14$

This is because

$K_{a}*K_{b}=10^{-14}$

$-log(K_{a}*K_{b})=-log(10^{-14})\\-logK_{a}+-logK_{b}=-log(10^{-14})\\pK_{a}+pK_{b}=14$

So then

$pK_{b}=14-pK_{a}=14-3.2=1.8$

7 0

3 years ago

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At a certain temperature the vapor pressure of pure benzene is measured to be . Suppose a solution is prepared by mixing of benz

Marianna [84]

Answer:

P(C₆H₆) = 0.2961 atm

Explanation:

I found an exercise pretty similar to this, so i'm gonna use the data of this exercise to show you how to do it, and then, replace your data in the procedure so you can have an accurate result:

<em>"At a certain temperature the vapor pressure of pure benzene (C6H6) is measured to be 0.63 atm. Suppose a solution is prepared by mixing 79.2 g of benzene and 115. g of heptane (C7H16) Calculate the partial pressure of benzene vapor above this solution. Round your answer to 2 significant digits. Note for advanced students: you may assume the solution is ideal".</em>

<em />

Now, according to the data, we want partial pressure of benzene, so we need to use Raoul's law which is:

P = Xₐ * P° (1)

Where:

P: Partial pressure

Xₐ: molar fraction

P°: Vapour pressure

We only have the vapour pressure of benzene in the mixture. We need to determine the molar fraction first. To do this, we need the moles of each compound in the mixture.

To get the moles: n = m / MM

To get the molar mass of benzene (C₆H₆) and heptane (C₇H₁₆), we need the atomic weights of Carbon and hydrogen, which are 12 g/mol and 1 g/mol:

MM(C₆H₆) = (12*6) + (6*1) = 78 g/mol

MM(C₇H₁₆) = (7*12) + (16*1) = 100 g/mol

Let's determine the moles of each compound:

moles (C₆H₆) = 79.2 / 78 = 1.02 moles

moles (C₇H₁₆) = 115 / 100 = 1.15 moles

moles in solution = 1.02 + 1.15 = 2.17 moles

To get the molar fractions, we use the following expression:

Xₐ = moles(C₆H₆) / moles in solution

Xₐ = 1.02 / 2.17 = 0.47

Finally, the partial pressure is:

P(C₆H₆) = 0.47 * 0.63

Hope this helps

7 0

2 years ago

I NEED HELP PLEASE, THANKS! :)

Leto [7]

Answer:

Here's what I get

Explanation:

i. E = mc²

E = energy

m = mass

c = the speed of light

"Energy equals mass times the square of the speed of light.”

The equation says that energy and mass are interchangeable. If you multiply the mass of an object by c², you get its equivalent and of energy.

The SI base units for energy are kg·m²s⁻².

The most common derived unit is the joule (J). Others are the newton-metre (N·m), kilowatt-hour (kWh), watt-second (W·s), and volt-coulomb (V·C).

ii. Nuclear vs chemical reactions

a. Alpha decay

$\rm _{92}^{238}\text{U} \longrightarrow \, _{2}^{4}\text{He} + \, _{90}^{234}\text{Th}$

A nuclear reaction — like α decay — takes place in the nucleus of an atom.

An element becomes a different element.

b. Chemical reaction

Na· + ·Cl ⟶ Na⁺ + Cl⁻

A chemical reaction — like the formation of NaCl — involves rearranging the electrons, which are outside the nucleus.

The elements do not change.

Salt still consists of sodium and chlorine.

8 0

2 years ago

The nucleus is held closely together by?

Hoochie [10]

The nucleus of an atom is held together by the strong nuclear force to hold together protons and neutrons. The strong nuclear force is stronger than electricity and gravity. It's even the strongest out of the four fundamental forces.

7 0

3 years ago

This reaction releases energy as heat. Explain whether it obeys the law of conservation of energy.

Anon25 [30]

The reaction that releases energy as heat is called an Exothermic reaction. This reaction does obey the law of conservation by preserving the energy present in the molecule and converting it to thermal heat to maintain it's from. Most reactions obey the law of conservation of energy.

4 0

3 years ago

Read 2 more answers