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Jobisdone [24]
3 years ago
7

Help! Will mark brainliest! Explain why a mechanical wave does not exist in a vacuum.

Chemistry
1 answer:
aniked [119]3 years ago
7 0

<span> Light waves are a wave in the electromagnetic field, this field may exist in a vacuum. Sound needs either solid, liquid, or gas to propagate and therefore it is called a mechanical wave. Sound is a form of energy which is transferred by vibrating air molecules if motions of propagation is air.</span>

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Galileo said that the Sun revolved around the Earth, and that the Earth was the center of the universe ! (:
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4 years ago
To prepare for a laboratory?
yKpoI14uk [10]

Answer:

You have to prepare for the lab (Materials, work, paper etc.)

Set up the lab know where the lab will be taking place

Read thru the experiment before doing the lab

Make a hypothesis

Write down notes, observations, measures anything important to help with the lab!

6 0
3 years ago
How do I "predict the colour change that would be observed if carbon dioxide gas were bubbled into a mixture of calcium oxide, b
Effectus [21]
Hey there!

Just say what color you think the mixture would look like if those elements were combined. Personally I don't know because I don't have context, but if it comes to it just pick a color :)

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7 0
3 years ago
Propose a mechanism for the following reaction.
raketka [301]
First, recognize that this is an elimination reaction in which hydroxide must leave and a double bond must form in its place. It is likely an E2 reaction. Here is an efficient mechanism:
1) Pre-reaction: Protonate the -OH to make it a good leaving group, water. H2SO4 or any strong H+ donor works. The water is positively charged but still connected to the compound.
2) E2: Use a sterically hindered base, such as tert-butoxide (tButO-) to abstract the hydrogen from the secondary carbon. [You want a sterically hindered base because a strong, non-sterically hindered base could also abstract a hydrogen from one of the two methyl groups on the tertiary carbon, and that leads to unwanted products, which is not efficient]. As the proton of hydrogen is abstracted, water leaves at the same time, creating an intermediate tertiary carbocation, and the 2 electrons in the C-H bond immediately are used to make a double bond towards the partial positive charge.
In the products we see the major product and water, as expected. Even though you have an intermediate, remember that an E2 mechanism technically happens in one step after -OH protonation. 
5 0
3 years ago
Sulfur dioxide has a vapor pressure of 462.7 mm Hg at –21.0 °C and a vapor pressure of 140.5 mm Hg at –44.0 °C. What is the enth
stealth61 [152]

Answer : The value of \Delta H_{vap} is 28.97 kJ/mol

Explanation :

To calculate \Delta H_{vap} of the reaction, we use clausius claypron equation, which is:

\ln(\frac{P_2}{P_1})=\frac{\Delta H_{vap}}{R}[\frac{1}{T_1}-\frac{1}{T_2}]

where,

P_1 = vapor pressure at temperature -21.0^oC = 462.7 mmHg

P_2 = vapor pressure at temperature -44.0^oC = 140.5 mmHg

\Delta H_{vap} = Enthalpy of vaporization = ?

R = Gas constant = 8.314 J/mol K

T_1 = initial temperature = -21.0^oC=[-21.0+273]K=252K

T_2 = final temperature = 45^oC=[-41.0+273]K=232K

Putting values in above equation, we get:

\ln(\frac{140.5mmHg}{462.7mmHg})=\frac{\Delta H_{vap}}{8.314J/mol.K}[\frac{1}{252}-\frac{1}{232}]\\\\\Delta H_{vap}=28966.6J/mol=28.97kJ/mol

Therefore, the value of \Delta H_{vap} is 28.97 kJ/mol

4 0
3 years ago
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