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3 years ago

Please help fast

Chemistry

1 answer:

Andrews [41]3 years ago

5 0

Answer: Change in energy

Explanation: The only evidence provided in the experimental statement is that the "solution turns warm." While the options include positive evidence of a chemical reaction, only "Change in energy" provides <u>both</u> evidence and correlation with an observation.

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Bromine, a liquid at room temperature has a boiling point of 58 degrees celsius and a melting point at -7.2 degree celsius bromi

ra1l [238]

Hello!

Bromine can be classified as a pure substance.

Why?

Bromine is an element with atomic number 35 on group 17 of the Periodic Table. That's the first sign that shows us that it is a pure substance.

But the fact that it has a clear and defined boiling and melting point is a sign that we are in the presence of a pure substance. Pure substances are characterized by defined boiling and melting points.

Mixtures usually have a range of temperatures in which they melt and boil.

Have a nice day!

8 0

3 years ago

Taryn has a 90-gram sample of ethanol, which has a specific heat of

Angelina_Jolie [31]

35 Celsius minus the average 20 Celsius. going to be 15. let me know if u need anything else.

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2 years ago

The atom with the same number of neutrons as 12C is 9Be. 11B. 13C. 14N.

julia-pushkina [17]

Answer : The atom with the same number of neutrons as $^{12}C$ is, $^{11}B$

Explanation :

The given atom is, $^{12}C$

Atomic mass number = 12

Atomic number = 6

Atomic number = Number of protons = Number of electrons = 6

Number of neutrons = Atomic mass number - Atomic number = 12 - 6 = 6

Now we have to determine the number of neutrons in the given options.

In atom, $^{9}Be$

Atomic mass number = 9

Atomic number = 4

Atomic number = Number of protons = Number of electrons = 4

Number of neutrons = Atomic mass number - Atomic number = 9 - 4 = 5

In atom, $^{11}B$

Atomic mass number = 11

Atomic number = 5

Atomic number = Number of protons = Number of electrons = 5

Number of neutrons = Atomic mass number - Atomic number = 11 - 5 = 6

In atom, $^{13}C$

Atomic mass number = 13

Atomic number = 6

Atomic number = Number of protons = Number of electrons = 6

Number of neutrons = Atomic mass number - Atomic number = 13 - 6 = 7

In atom, $^{14}N$

Atomic mass number = 14

Atomic number = 7

Atomic number = Number of protons = Number of electrons = 7

Number of neutrons = Atomic mass number - Atomic number = 14 - 7 = 7

Therefore, the atom with the same number of neutrons as $^{12}C$ is, $^{11}B$

6 0

3 years ago

What elements form chlorides with formula xcl?

dolphi86 [110]

<span>Since chlorine favours a (-1) oxidation state, it forms an ionic bond with group one metals with the formula XCl. All group one metals react vigorously with chlorine gas; and each reaction gets more violent as you move down Group 1 and produces a white crystalline salt. The reaction with chlorine is as follows 2X + Cl2 which gives 2XCl. Where X is an Alkali metal.</span>

4 0

2 years ago

Be sure to answer all parts. treatment of (hoch2ch2ch2ch2)2co with acid forms a product of molecular formula c9h16o2 and a molec

liubo4ka [24]

The reaction described above is the formation of an acetal. The initial starting material has a central carbonyl and two terminal alcohol functional groups. In the presence of acid, the carbonyl will become protonated, making the carbon of the carbonyl susceptible to nucleophilic attack from one of the alcohols. The alcohol substitutes onto the carbon of the carbonyl to provide us with the intermediate shown.

The intermediate will continue to react in the presence of acid and the -OH that was once the carbonyl will become protonated, turning it into a good leaving group. The protonated alcohol leaves and is substituted by the other terminal alcohol to give the final acetal product. The end result of the overall reaction is the loss of water from the original molecule to give the spiroacetal shown in the image provided.

5 0

3 years ago