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3 years ago

Which is an example of a chemical change

Chemistry

2 answers:

pickupchik [31]3 years ago

7 0

The chemical change is substances that are changed into different substances like fireworks

hammer [34]3 years ago

4 0

Development of carbonation

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Which kelvin temperature is equal to -73 c?

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The conversation rate is c+273=k

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3 years ago

How many moles of HCl are present in 40.0 mL of a 0.035 M solution? 1. 0.0014 mol 2. 0.0060 mol 3. 0.25 mol?

Vinil7 [7]

40.0mL(1 L/1000 mL) = 0.040 L

<span>then plug into the formula M = moles/liters </span>

<span>0.035 M = moles/ 0.040L </span>

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<span>so the answer is 1</span>

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3 years ago

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anzhelika [568]

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3 years ago

Read 2 more answers

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

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

$P = 39.8 \ mg$

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3 years ago

Determine the electron-group arrangement, molecular shape, and ideal bond angle(s) for each of the following:

antoniya [11.8K]

The electron group arrangement of PH₃ is tetrahedral. The molecular shape is a Trigonal pyramid, and the bond angle is 93°.

<h3>What is the bond angle?</h3>

The angle between the atoms in a compound is known as the bond angle. The degree of the binding angle is specified. There is also the bond length. It is the separation between the two atoms' nuclei.

The bond angle between the atoms of phosphine is 93°. It has one lone pair. The central atom is covered with 4 atoms.

Thus, the electron-group arrangement of phosphine is tetrahedral. The molecular geometry or shape is a trigonal pyramid. The bond angle is 93°.

To learn more about bond angles, refer to the link:

brainly.com/question/1851495

#SPJ4

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2 years ago