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3 years ago

Time zones were adopted to fix what problem

Chemistry

2 answers:

morpeh [17]3 years ago

8 0

Time Zones were adopted to fix the time. Without the time zone, you will never know what time it is

SCORPION-xisa [38]3 years ago

5 0

To know when the sun goes up and down

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Calculate the standard entropy of vaporization of ethanol, C2H5OH, at 285.0 K, given that the molar heat capacity at constant pr

MArishka [77]

Answer: The standard entropy of vaporization of ethanol is 0.275 J/K

Explanation:

$C_2H_5OH(l)\rightleftharpoons C_2H_5OH(g)$

Using Gibbs Helmholtz equation:

$\Delta G=\Delta H-T\Delta S$

For a phase change, the reaction remains in equilibrium, thus $\Delta G=0$

$\Delta H=T\Delta S$

Given: Temperature = 285.0 K

$\Delta H=78.3J/mol$

Putting the values in the equation:

$78.3J=285.0K\times \Delta S$

$\Delta S=0.275J/K$

Thus the standard entropy of vaporization of ethanol is 0.275 J/K

4 0

4 years ago

A bike rider approaches a hill with a speed of 8.5 m/s. The total mass of the bike and the rider is 85 kg. Find the kinetic ener

krek1111 [17]

KE=3070.625 J

Height = 3.686 m

<h3>Further explanation</h3>

mass of bike+rider=85 kg

velocity = 8.5 m/s

$\tt KE=\dfrac{1}{2}mv^2\\\\KE=\dfrac{1}{2}\times 85\times 8.5^2\\\\KE=3070.625~J$

Conservation of energy :

(KE+PE)₁ (downhill) = (KE+PE)₂ (up the hill)

PE₁=0⇒h=0

KE₂=0⇒v=0(stop), so equation becomes :

KE₁=PE₂

$\tt KE_1=3070.625\\\\KE_1=mgh_2\\\\3070.625=85\times 9.8\times h\Rightarrow h=3.686~m$

5 0

3 years ago

Not enough air is pumped into an inflatable life raft to make completely filled out the atm pressure is 14.7psi what is the pres

sasho [114]

If you do not inflate the life raft to make completely filled out, as long as you do not press or squeeze the life raft, the air inside it will be in equilibrium with the air outside the raft, and so the pressure inside the life raft will be the same atmospheric pressure, 14.7 psi.

Note that when the raft is swollen, if you punch it, the air will leave from it which means that the pressure inside is greater than the atmospheric pressure.

5 0

3 years ago

In a common experiment in the general chemistry laboratory, magnesium metal is heated in air to produce MgO. MgO is a white soli

Digiron [165]

Explanation:

When magnesium metal burns is heated i the air it forms magnesium oxide.The balanced chemical reaction is given as:

$2Mg+O_2\rightarrow 2MgO$

2 moles of magnesium metal when reacts with 1 moles of oxygen it gives 2 moles of magnesium oxide which is white in color.

Some times along with formation of magnesium oxide small amount of magnesium nitride also produced due to which magnesium oxide appears grey in color .The balanced chemical reaction is given as:

$3Mg+N_2\rightarrow Mg_3N_2$

3 moles of magnesium combines with 1 mol of nitrogen gas to to give 1 mol of magnesium nitride.

6 0

3 years ago

Please check if i did it right. did i put the right electric charge

Ad libitum [116K]

Your protons are correct but it’s 28 neutrons not 27!

6 0

3 years ago