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3 years ago

The color change in the titration of KMnO4 with oxalic acid at the endpoint is:

Chemistry

1 answer:

Romashka-Z-Leto [24]3 years ago

7 0

Answer:

d. Colorless to pink

Explanation:

The color change in the titration of KMnO4 with oxalic acid at the endpoint is colorless to pink.

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A mixture of water and graphite is heated to 600 K in a 1 L container. When the system comes to equilibrium it contains 0.17 mol

Kryger [21]

Answer:

0.44 moles

Explanation:

Given that :

A mixture of water and graphite is heated to 600 K in a 1 L container. When the system comes to equilibrium it contains 0.17 mol of H2, 0.17 mol of CO, 0.74 mol of H2O, and some graphite.

The equilibrium constant $K_c= \dfrac{[CO][H_2]}{[H_2O]}$

The equilibrium constant $K_c= \dfrac{(0.17 )(0.17)}{0.74}$

The equilibrium constant $K_c= 0.03905$

Some O2 is added to the system and a spark is applied so that the H2 reacts completely with the O2.

The equation for the reaction is :

$H_2 + \dfrac{1}{2}O_2 \to H_2O \\ \\ 0.17 \ \ \ \ \ \ \ \ \ \to0.17$

Total mole of water now = 0.74+0.17

Total mole of water now = 0.91 moles

Again:

$K_c= \dfrac{[CO][H_2]}{[H_2O]}$

$0.03905 = \dfrac{[0.17+x][x]}{[0.91 -x]}$

0.03905(0.91 -x) = (0.17 +x)(x)

0.0355355 - 0.03905x = 0.17x + x²

0.0355355 +0.13095 x -x²

x² - 0.13095 x - 0.0355355 = 0

By using quadratic formula

x = 0.265 or x = -0.134

Going by the value with the positive integer; x = 0.265 moles

Total moles of CO in the flask when the system returns to equilibrium is :

= 0.17 + x

= 0.17 + 0.265

= 0.435 moles

=0.44 moles (to two significant figures)

3 0

3 years ago

What does ClF3 stand for

Nostrana [21]

Answer:

CHLORINE TRIFLUORIDE

Explanation:

3 0

3 years ago

Using your knowledge of reagents that react with alkenes, what would be a reagent that you could use to check and see if the hyd

igomit [66]

Answer:

An halogen addition reaction, particularly bromine addition, could be used to check if the hydrogenation has completed.

Explanation:

The aim is to find a way to check if the hydrogenation process of an alkene has completed. So the logic should be use a reaction that needs the participation of the double bound of the alkene, and therefore shouldn't take place in the process has finished.

A simple organic reaction is the halogen addition reaction, which occur between the halogen molecule and the double bond of the alkene. Basically, the pi electrons of the double bond attacks a relatively electrophilic halogen atom following a mechanism that leads to the addition of two halogen atoms to the double bond. As a consequence the alkene transforms into an haloalkane.

Also, a commonly used halogen is bromine, as it has a reasonable reactivity and it has red colour, which allows to monitor the progression of the reaction.

Taking all this in account, we can say that using a bromine addition reaction to the alkene it's a good option to check the completion of the hydrogenation.

Note that the bromine will react only if the double bond is present. So, if the hydrogenation has completed, the reaction won't occur. Using bromine will be the best option, as it is red coloured. That means that is we add bromine to an incomplete hydrogenation, as it will react with the alkene, the colour should disappear.

In other words, to check if the hydrogenation reaction has completed, we should add bromine and see what happens to the colour. If it doesn't change, then the hydrogenation reaction has completed.

3 0

3 years ago

An element in group 7 on the periodic table most likely has which physical property?

larisa86 [58]

Answer:

They are most likely solid

Explanation:

solid is a physical property

3 0

3 years ago

Help please due today

Usimov [2.4K]

The one abt respiration the answer is the first one and circulatory system is the last one that says “delivery molecules …”

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2 years ago

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