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3 years ago

Which of the following is not an example of a chemical change?

Chemistry

2 answers:

leva [86]3 years ago

6 0

Answer:

cutting paper is not an example of chemical change.

Explanation:

cutting paper is physical change, its physical properties (size, shape ) change but chemical composition remain same.

JulsSmile [24]3 years ago

5 0

Answer:

It is C

Explanation:

It is Cutting paper because cutting paper doesn't alter the chemical composition of paper

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While finding the number of molecules of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be

zvonat [6]

Answer

Avogadro's number: One mole of any substance contains 6.022×10²³ molecules

Explanation

While finding the number of moles of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be Avodagro's number, which is

One mole of any substance contains 6.022×10²³ molecules.

8 0

1 year ago

Which of the following describes scientists?

serious [3.7K]

I believe the answer I’d D

Hope it helps

3 0

3 years ago

The most unusual characteristic of Uranus is _____.

fiasKO [112]

Answer:

the axis is tilted at 98 degrees

Explanation:

Uranus is blue, not green; it has an atmosphere of hydrogen and helium, not methane. While it does have an icy cold temperature, that's not a very unusual characteristic for an outer planet. However, the tilt of the axis is unusual; no other planet is tilted almost completely on its side!

6 0

3 years ago

While ethanol is produced naturally by fermentation, e.g. in beer- and wine-making, industrially it is synthesized by reacting e

sp2606 [1]

The question is incomplete, here is the complete question:

While ethanol is produced naturally by fermentation, e.g. in beer- and wine-making, industrially it is synthesized by reacting ethylene with water vapor at elevated temperatures.

A chemical engineer studying this reaction fills a 1.5 L flask at 12°C with 1.8 atm of ethylene gas and 4.7 atm of water vapor. When the mixture has come to equilibrium she determines that it contains 1.16 atm of ethylene gas and 4.06 atm of water vapor.

The engineer then adds another 1.2 atm of ethylene, and allows the mixture to come to equilibrium again. Calculate the pressure of ethanol after equilibrium is reached the second time. Round your answer to 2 significant digits.

Answer: The partial pressure of ethanol after equilibrium is reached the second time is 1.0 atm

Explanation:

We are given:

Initial partial pressure of ethylene gas = 1.8 atm

Initial partial pressure of water vapor = 4.7 atm

Equilibrium partial pressure of ethylene gas = 1.16 atm

Equilibrium partial pressure of water vapor = 4.06 atm

The chemical equation for the reaction of ethylene gas and water vapor follows:

$CH_2CH_2(g)+H_2O(g)\rightleftharpoons CH_3CH_2OH(g)$

Initial: 1.8 4.7

At eqllm: 1.8-x 4.7-x

Evaluating the value of 'x'

$\Rightarrow (1.8-x)=1.16\\\\x=0.64$

The expression of $K_p$ for above equation follows:

$K_p=\frac{p_{CH_3CH_2OH}}{p_{CH_2CH_2}\times p_{H_2O}}$

$p_{CH_2CH_2}=1.16atm\\p_{H_2O}=4.06atm\\p_{CH_3CH_2OH}=0.64atm$

Putting values in above expression, we get:

$K_p=\frac{0.64}{1.16\times 4.06}\\\\K_p=0.136$

When more ethylene is added, the equilibrium gets re-established.

Partial pressure of ethylene added = 1.2 atm

$CH_2CH_2(g)+H_2O(g)\rightleftharpoons CH_3CH_2OH(g)$

Initial: 2.36 4.06 0.64

At eqllm: 2.36-x 4.06-x 0.64+x

Putting value in the equilibrium constant expression, we get:

$0.136=\frac{(0.64+x)}{(2.36-x)\times (4.06-x)}\\\\x=0.363,13.41$

Neglecting the value of x = 13.41 because equilibrium partial pressure of ethylene and water vapor will become negative, which is not possible.

So, equilibrium partial pressure of ethanol = (0.64 + x) = (0.64 + 0.363) = 1.003 atm

Hence, the partial pressure of ethanol after equilibrium is reached the second time is 1.0 atm

3 0

3 years ago

How many electrons will metals generally have in their outer shell

Goshia [24]

Answer:

1 - 3

Explanation:

- Look to see where metals are on the periodic table then look at what group they are in. The group tells you the number of valence electrons. Ex. 1A has one valence electron.

- Hope this helped! If you need a further explanation please let me know.

3 0

3 years ago