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2 years ago

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A nitrogen gas collected in a tube has a volume of 0.86 mL, a temperature of 316.48 degrees kelvin, and a pressure 1.17 atm. Two

days later, the volume of the nitrogen was 1.06 mL but the pressure did not change. What was the temperature two days later

1 answer:

rewona [7]2 years ago

6 0

Use the formula PV=NRT to find the amount of moles of nitrogen gas. Then use the same formula using the amount of moles found to find the temperature

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The experiment above is repeated, but instead of extracting once with 6 mL the extraction is done three times with 2 mL of dichl

nevsk [136]

Complete Question

A student is extracting caffeine from water with dichloromethane. The K value is 4.6. If the student starts with a total of 40 mg of caffeine in 2 mL of water and extracts once with 6 mL of dichloromethane

The experiment above is repeated, but instead of extracting once with 6 mL the extraction is done three times with 2 mL of dichloromethane each time. How much caffeine will be in each dichloromethane extract?

Answer:

The mass of caffeine extracted is $P = 39.8 \ mg$

Explanation:

From the question above we are told that

The K value is $K = 4.6$

The mass of the caffeine is $m = 40 mg$

The volume of water is $V = 2 mL$

The volume of caffeine is $v_c = 2 mL$

The number of times the extraction was done is n = 3

Generally the mass of caffeine that will be extracted is

$P = m * [\frac{V}{K * v_c + V} ]^3$

substituting values

$P = 40 * [\frac{2}{4.6 * 2 + 2} ]^3$

$P = 39.8 \ mg$

6 0

3 years ago

An unknown salt is either NaF, NaCl, or NaOCl. When 0.050 mol of the salt is dissolved in water to form 0.500 L of solution, the

victus00 [196]

<u>Answer:</u> The unknown salt is NaF

<u>Explanation:</u>

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Moles of salt = 0.050 moles

Volume of solution = 0.500 L

Putting values in above equation, we get:

$\text{Molarity of salt}=\frac{0.050mol}{0.500L}\\\\\text{Molarity of salt}=0.1M$

To calculate the hydroxide ion concentration, we first calculate pOH of the solution, which is:

pH + pOH = 14

We are given:

pH = 8.08

$pOH=14-8.08=5.92$

To calculate pOH of the solution, we use the equation:

$pOH=-\log[OH^-]$

Putting values in above equation, we get:

$5.92=-\log[OH^-]$

$[OH^-]=10^{-5.92}=1.202\times 10^{-6}M$

The unknown salt given are formed by the combination of weak acid and strong acid which is NaOH

The chemical equation for the hydrolysis of $X^-$ ions follows:

$X^-(aq.)+H_2O(l)\rightleftharpoons HX(aq.)+OH^-(aq.);K_b$

<u>Initial:</u> 0.1

<u>At eqllm:</u> 0.1-x x x

Concentration of $OH^-=x=1.202\times 10^{-6}M$

The expression of $K_b$ for above equation follows:

$K_b=\frac{[OH^-][HX]}{[X^-]}$

Putting values in above expression, we get:

$K_b=\frac{(1.202\times 10^{-6})\times (1.202\times 10^{-6})}{(1-(1.202\times 10^{-6}))}\\\\K_b=1.445\times 10^{-11}M$

To calculate the acid dissociation constant for the given base dissociation constant, we use the equation:

$K_w=K_b\times K_a$

where,

$K_w$ = Ionic product of water = $10^{-14}$

$K_a$ = Acid dissociation constant

$K_b$ = Base dissociation constant = $1.445\times 10^{-11}$

Putting values in above equation, we get:

$10^{-14}=1.445\times 10^{-11}\times K_a\\\\K_a=\frac{10^{-14}}{1.445\times 10^{-11}}=6.92\times 10^{-4}$

We know that:

$K_a\text{ for HF}=6.8\times 10^{-6}$

$K_a\text{ for HCl}=1.3\times 10^{6}$

$K_a\text{ for HClO}=3.0\times 10^{-8}$

So, the calculated $K_a$ is approximately equal to the $K_a$ of HF

Hence, the unknown salt is NaF

6 0

3 years ago

What is the temperature of 0.500 moles of helium that occupies a volume of 15.0 L at a pressure of 1.6 atm?

denis23 [38]

Answer:

600K

Explanation:

PV=nRT

T=PV/nR

= 1.6atm* 15.0L/ 0.5mol*0.0821LatmK^-1mol^-1

=600K

6 0

3 years ago

Describe the three main types of plate boundary interactions:

bulgar [2K]

Answer:

In the explanation

Explanation:

Divergent: When two plates are diverging from each other, meaning that the two plates are moving away from each other. Events that may occur include ridges or rifts.

Convergent: When two plates are moving towards each other.

If a continental plate and an oceanic plate are converging, the oceanic plate would slide underneath the continental plate since it is thinner. This would result in subduction, which means that part of the oceanic plate would hang underneath the continental plate, where magma can melt the hanging part.

If two continental plates are converging, the crash would result in mountains or volcanic activity. Magma could rise and rush from the crack. There would be a bump in these tectonic plates.

Transform: When two plates are sliding past each other. Earthquakes can occur when the plates are sliding. When an oceanic plate is involved, the movement of the plates could cause a tsunami as well. The water above the transform fault could rise, and grow bigger and bigger. The 2011 Japan Tsunami is a good example of this.

Hope this helps!

5 0

2 years ago

Wskaż substancję, która ma największą zawartość procentową węgla w cząsteczce:

MrRa [10]

Answer: C2H4

Explanation:

The percentage composition of ethanol ( C2H5OH ) consist of 52.2% Carbon, Hydrogen of 13.0 and 34.8% of Oxygen.

The percentage composition of ethane gas (C2H6) consist of 80.0% carbon and 20.0% hydrogen.

The composition of Ethylene Glycols i.e C2H4(OH)2 is Carbon of 39.7%, 9.7% hydrogen and 51.6% oxygen.

The percent composition of c2h4 is 86% carbon, and 14% hydrogen.

From the information given, the substance with the highest percentage of carbon is C2H4

7 0

3 years ago